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Thursday, August 7, 2025

Buddhism and violence

From Wikipedia, the free encyclopedia

Buddhism and violence looks at the historical and current examples of violent acts committed by Buddhists or groups connected to Buddhism, as well as the larger discussion of such behaviour within Buddhist traditions. Although Buddhism is generally seen as a religion that promotes compassion, nonviolence (ahimsa), and the reduction of suffering, there have been instances throughout its history where violence has been condoned or carried out in the name of Buddhist organisations or ideals. These include instances of Buddhist players participating in nationalist movements, sectarian conflicts, and monastic support for military actions.

Whether these incidents show how religion interacts with political, cultural, and social forces or whether they are departures from the essential teachings of Buddhism is a matter of debate among scholars. Examining how Buddhist teaching is interpreted and applied in various historical and geographical circumstances is still a focus of scholarly investigation.

According to one analysis, Buddhist violence tends to occur when the state and Buddhism are closely intertwined, as it emboldens Buddhist vigilantes to attack religious minorities.

Teachings, interpretations, and practices

Bhikkhus, even if bandits were to sever you savagely limb by limb with a two-handled saw, he who gave rise to a mind of hate towards them would not be carrying out my teaching.

— Kakacūpama Sutta, Majjhima-Nikāya 28 at MN i 128-29

Buddhism encompasses a variety of traditions, beliefs and spiritual practices largely based on teachings attributed to Gautama Buddha.

Nirvana is the oldest and most common term for the end goal of the Buddhist path and the ultimate eradication of duḥkha—nature of life that innately includes "suffering", "pain", or "unsatisfactoriness". Violent actions and thoughts—actions that harm and debase others and thoughts that contemplate the same—stand in the way of spiritual growth and the self-conquest that leads to the goal of existence, and they are normally deemed unskilled (akusala) and cannot lead to the goal of Nirvana. Buddha condemned killing or harming living beings and encouraged reflection or mindfulness (satipatthana) as right action (or conduct), therefore "the rightness or wrongness of an action centers around whether the action itself would bring about harm to self and/or others". In the Ambalatthika-Rahulovada Sutta, the Buddha says to Rahula:

If you, Rahula, are desirous of doing a deed with the body, you should reflect on the deed with the body, thus: That deed which I am desirous of doing with the body is a deed of the body that might conduce to the harm of self and that might conduce to the harm of others and that might conduce to the harm of both; this deed of body is unskilled (akusala), its yield is anguish, its result is anguish.

The right action or right conduct (samyak-karmānta / sammā-kammanta) is the fourth aspect of the Noble Eightfold Path and it said that the practitioner should train oneself to be morally upright in one's activities, not acting in ways that would be corrupt or bring harm to oneself or to others. In the Chinese and Pali Canon, it is explained as:

And what is right action? Abstaining from taking life, from stealing, and from illicit sex [or sexual misconduct]. This is called right action.

— Saccavibhanga Sutta

For the lay follower, the Cunda Kammaraputta Sutta elaborates:

And how is one made pure in three ways by bodily action? There is the case where a certain person, abandoning the taking of life, abstains from the taking of life. He dwells with his... knife laid down, scrupulous, merciful, compassionate for the welfare of all living beings. Abandoning the taking of what is not given, he abstains from taking what is not given. He does not take, in the manner of a thief, things in a village or a wilderness that belong to others and have not been given by them.

Sarambha can be translated as "accompanied by violence". As the mind filled with lobha, dosa and moha (lust, hatred and delusion) is led to actions which are akusala. Indulging in violence is a form of self-harming. The rejection of violence in society is recognized in Buddhism as a prerequisite for the spiritual progress of society's members, because violence brings pain to beings with similar feelings to oneself. The Buddha is quoted in the Dhammapada as saying, "All are afraid of the stick, all hold their lives dear. Putting oneself in another's place, one should not beat or kill others". Metta (loving kindness), the development of mindstates of limitless good-will for all beings, and karuna, compassion that arises when you see someone suffering of the human being, are attitudes said to be excellent or sublime because they are the right or ideal way of conduct towards living beings (sattesu samma patipatti). The Sutta Nipata says "'As I am, so are these. As are these, so am I.' Drawing the parallel to yourself, neither kill nor get others to kill."

In Buddhism, to take refuge in the Dharma—one of the Three Jewels—one should not harm other sentient beings. The Nirvana Sutra states, "By taking refuge in the precious Dharma, One's minds should be free from hurting or harming others". One of the Five Precepts of Buddhist ethics or śīla states, "I undertake the training rule to abstain from killing." The Buddha reportedly stated, "Victory breeds hatred. The defeated live in pain. Happily the peaceful live giving up victory and defeat." These elements are used to indicate Buddhism is pacifistic and all violence done by Buddhists, even monks, is likely due to economic or political reasons.

The teaching of right speech (samyag-vāc / sammā-vācā) in the Noble Eightfold Path, condemn all speech that is in any way harmful (malicious and harsh speech) and divisive, encouraging to speak in thoughtful and helpful ways. The Pali Canon explained:

And what is right speech? Abstaining from lying, from divisive speech, from abusive speech, and from idle chatter: This is called right speech.

Michael Jerryson, Associate Professor of Religious Studies at Ohio's Youngstown State University and co-editor of the book Buddhist Warfare, said that "Buddhism differs in that the act of killing is less the focus than the 'intention' behind the killing" and "The first thing to remember is that people have a penchant for violence, it just so happens that every religion has people in it."

Gananath Obeyesekere, Emeritus Professor of Anthropology at Princeton University, said that "in the Buddhist doctrinal tradition... there is little evidence of intolerance, no justification for violence, no conception even of 'just wars' or 'holy wars.' ... one can make an assertion that Buddhist doctrine is impossible to reconcile logically with an ideology of violence and intolerance"

"Killing to save lives" is, uniquely amongst Buddhist schools, considered justified by certain Mahayana scriptures such as the Upaya-kaushalya Sutra, where, in a past life, Shakyamuni Buddha kills a robber intent on mass murder on a ship (with the intent both of saving the lives of the passengers and saving the robber from bad karma). K. Sri Dhammananda taught warfare is accepted as a last resort, quoting the Buddha's conversation with a soldier. The 14th Dalai Lama has also spoken on when it is permissible to kill another person. During a lecture he was giving at Harvard University in 2009, the Dalai Lama invoked the Upaya-kaushalya Sutra and said that "wrathful forceful action" motivated by compassion, may be "violence on a physical level" but is "essentially nonviolence", and we must be careful to understand what "nonviolence" means. Following the killing of Osama bin Laden in 2011, the Dalai Lama endorsed his killing, stating "Forgiveness doesn't mean forget what happened. ... If something is serious and it is necessary to take counter-measures, you have to take counter-measures." During a question panel in 2015, in which he was asked if it would be justified to kill Hitler, Stalin, Pol Pot, or Mao while they were early into their campaigns of genocide, the Dalai Lama stated that it would be justified, so long as they were not killed in anger.

In addition capital punishment for murder is justified according to this interpretation of Buddhism because the Judge is not seen as causing death but rather the actions of the murderer executed are.

There is also in Buddhism a long tradition of self-inflicted violence and death, as a form of asceticism or protest, as exemplified by the use of fires and burns to show determinations among Chinese monks, by the self-immolations of monks such as Thích Quảng Đức during the Vietnam war or Tibetan monks in support of Tibetan independence.

Regional examples

Southeast Asia

Thailand

Kittivuddho (see, Kittiwuttho, spelling in translation varies) was a staunch follower of the Thai Sangha - the religious organization that leads the Buddhist movement in Thailand. The Sangha offers validity to the Thai government. If the ruling body shows fealty to the Sangha, then their actions are seen as legitimized and moral via the association. Likewise, the Sangha receives power and influence through the recognition of their partnership with the ruling government.

A yellow flag with a saffron-orange flower in the center
Thai Buddhist Flag

In the 1900s, the outbreak of World War 1 impacted then King of Siam, King Rama VI. Rama VI had studied and trained with the military in London, and thus felt it necessary to show his support for the allied forces. Thailand would not have been affected by the fighting in the West, nevertheless, Siam sent a voluntary cohort of 1,200 troops. Although they arrived too late to participate in the fighting, Rama VI received critical feedback from Abbot Phra Thep Moli Sirichantoe.

The Abbot's critique of Rama VI's decision - published in a book criticizing military knowledge as "evil", was likewise counter-critiqued by the Supreme Patriarch (at the time, Rama VI's uncle). The Supreme Patriarch brought attention to the concept of sacrifice in Buddhist teachings, and thus likened it to the sacrifice soldiers must make in defense of their homeland. In so doing, he used the teachings of Buddha to justify the violence thought necessary to protect a nation or culture in times of war, and the need to prepare for war in times of peace.

Two Buddhist Monks in Saffron robes with shaved heads and amber-brown skin stand over a pillar adorned with yellow flora. Two soldiers in green camo and bucket hats present the pillar to the monks.
Thai Buddhist Monks blessing the primary pillar of a school during Exercise Cobra Gold - a set of humanitarian exercises in Thailand

The Supreme Patriarch likened the King's decisions to the necessary role of the leader or protector of a group or family to take the risk in leading others. The Supreme Patriarch quoted an ancient saying, "When a herd of cattle is fording a stream, if the leading ox leads straight, all the oxen will follow straight." Additionally, he compared the role of king or leader to that of a parent, who must ensure a child takes bitter medicine in times of illness. In so doing, he supports his argument that the King knew better than the Abbot, or than the citizenry, in his choice to supply soldiers to the Western Conflict in World War I.

These arguments, based in ancient proverb and justified through Buddhist relations of sacrifice, directly strike against the ancient story of Temija - a past life of Buddha that was shocked and appalled by the use of violence by governing leaders. While the story of Temija teaches against the use of violence in forms of punishment, the Supreme Patriarch instead utilized the concepts of sacrifice put forth through other Buddhist teachings to justify the use of violence by leaders, even to the point that violence for the sake of the nation would be viewed as virtuous.

1970s Thai Buddhism:

In the 1970s, Kittivuddho - a prominent Buddhist monk with influence in Thai culture - stated in an interview with Caturat (a news magazine from the period) that killing communists is, "not de-meritorius". Kittivuddho's assertion that the killing of Communists is forgiveable for Buddhists reflects earlier philosophies from Asanga and Buddhaghosa. Against the assertions sixty years prior of Phra Thep Moli, Kittivuddho did not see acts of violence and killing as a demerit within certain contexts.

These remarks followed the 1973 student-led uprising, as well as the creation of a Thai parliament and the spread of communism in neighboring East Asian countries. The fear of communism shaking the social forms of Thailand felt a very real threat to Kittivuddho, who expressed his nationalist tendencies in his defense of militant actions. He justified his argument by dehumanizing the Communists and leftists that he opposed. In the interview with Caturat he affirmed that this would not be the killing of people, but rather the killing of monsters/devils. He similarly asserted that while killing of people is prohibited and thus de-meritorious in Buddhist teachings, doing so for the "greater good" will garner greater merit than the act of killing will cost.

Kittivuddho's statements in the 1970s reflect the argument made in defense of King Rama VI by the Supreme Patriarch following the events of WWI. Kittivuddho, likewise, justifies his approval of the killing of communists by claiming that in so doing, the soldiers who commit these acts will gain greater merit than they will lose from the act. Like the Supreme Patriarch, he utilizes the concept of sacrifice for the sake of defending, "the country, the religion, and the institution of monarchy."

"He taught us to kill. Venerable sirs, you are likely to be suspicious about this teaching. I will tell you the sutta and you can investigate: (It is) the Kesi-sutta in the Kesiya-vagga, the sutta-nipitaka, anguttara-nikaya, catu-kaka-nipata. If you open (this text) venerable sirs, you will find that the Lord Buddha ordered killing."

Kittivuddho, Gillberg, Christina 2006

Feelings of patriotism and the sense of national security are valued more highly than human lives in Kittivuddho's argument. Since defending the nation becomes the highest priority, or highest "value" for Thai Buddhist philosophy, the act of killing is seen as a sacrifice made by the killer, but one that is justified. By manipulating the literal definition of the words within Buddhist scriptures, Kittivuddho was able to support his position.

Thailand in the 2000s

Religious tensions in Thailand are directly related to the state's choice to represent Buddhism as the de facto state religion. The Thai monk is no longer only a Thai practitioner of Buddhism, but a figure for the Thai state. As the Thai monk has become an iconic representative of the Thai nation state, the refusal to acknowledge and/or the mistreatment of other religious practitioners in Thailand has resulted in strained relationships between religions. Such as in the early 2000s, when conflict between Malay Muslims (citizens and militants) began to rise in the southernmost provinces of Thailand, and less so between Thai Buddhist and Thai-Chinese Buddhists.

This rise in militant interactions rose with prominent events in 2004, and continued to build. On April 28th, 2004, the Thai military assaulted the Khru Se Mosque, resulting in over 100 deaths of militant Malay Muslims. That same October, peacefully protesting Malay Muslim citizens were met with intense police brutality, wherein the Thai military fired upon and suffocated as many as 80 Malay Muslim citizens

Myanmar

In recent years the State Peace and Development Council (SPDC), the military regime of Burma from 1988 to 2011, had strongly encouraged the conversion of ethnic minorities, often by force, as part of its campaign of assimilation. The regime promoted a vision of Burmese Buddhist nationalism as a cultural and a political ideology to legitimise its contested rule, trying to bring a religious syncretism between Buddhism and its totalitarian ideology.

The Saffron Revolution, a series of economic and political protests and demonstrations that took place during 2007, were led by students, political activists, including women, and Buddhist monks and took the form of a campaign of nonviolent resistance, sometimes also called civil resistance.

In response to the protests dozens of protesters were arrested or detained. Starting in September 2007 the protests were led by thousands of Buddhist monks, and those protests were allowed to proceed until a renewed government crackdown in late September 2007. At least 184 protesters were shot and killed and many were tortured. Under the SPDC, the Burmese army engaged in military offensives against ethnic minority populations, committing acts that violated international humanitarian law.

Flag of the Democratic Karen Buddhist Army

Myanmar had become a stronghold of Buddhist aggression and such acts are spurred by hardline nationalistic monks. The oldest militant organisation active in the region is Democratic Karen Buddhist Army (DKBA), headed by a Buddhist monk U Thuzana, since 1992. In the recent years the monks, and the terrorist acts, are associated with the nationalist 969 Movement particularly in Myanmar and neighboring nations. The violence reached prominence in June 2012 when more than 200 people were killed and around 100,000 were displaced. As of 2012, the "969" movement by monks (the prominent among whom is Wirathu) had helped create anti-Islamic nationalist movements in the region, and have urged Myanmar Buddhists to boycott Muslim services and trades, resulting in persecution of Muslims in Burma by Buddhist-led mobs. However, not all of the culprits were Buddhists and the motives were as much economic as religious. On 20 June 2013, Wirathu was mentioned on the cover story of Time magazine as "The Face of Buddhist Terror". According to the Human Rights Watch report, the Burmese government and local authorities played a key role in the forcible displacement of more than 125,000 Rohingya people and other Muslims in the region. The report further specifies the coordinated attacks of October 2012 that were carried out in different cities by Burmese officials, community leaders and Buddhist monks to terrorize and forcibly relocate the population. The violence of Meiktila, Lashio (2013) and Mandalay (2014) are the latest Buddhist violence in Burma.

Michael Jerryson, author of several books heavily critical of Buddhism's traditional peaceful perceptions, stated that, "The Burmese Buddhist monks may not have initiated the violence but they rode the wave and began to incite more. While the ideals of Buddhist canonical texts promote peace and pacifism, discrepancies between reality and precepts easily flourish in times of social, political and economic insecurity, such as Myanmar's current transition to democracy."

However several Buddhist leaders including Thích Nhất Hạnh, Bhikkhu Bodhi, Shodo Harada and the Dalai Lama among others condemned the violence against Muslims in Myanmar and called for peace, supporting the practice of the fundamental Buddhist principles of non-harming, mutual respect and compassion. The Dalai Lama said "Buddha always teaches us about forgiveness, tolerance, compassion. If from one corner of your mind, some emotion makes you want to hit, or want to kill, then please remember Buddha's faith. We are followers of Buddha." He said that "All problems must be solved through dialogue, through talk. The use of violence is outdated, and never solves problems."

Maung Zarni, a Burmese democracy advocate, human rights campaigner, and a research fellow at the London School of Economics who has written on the violence in Myanmar and Sri Lanka, states that there is no room for fundamentalism in Buddhism. "No Buddhist can be nationalistic", said Zarni, "There is no country for Buddhists. I mean, no such thing as 'me,' 'my' community, 'my' country, 'my' race or even 'my' faith."

South Asia

India

Ashokavadana (a text from 3rd cent CE) states that there was a mass killing of Ajivikas for drawing a figure of the Buddha bowing down to the Nataputta by Emperor Ashoka in which around 18,000 Ajivikas were killed. However this account is controversial. According to K. T. S. Sarao and Benimadhab Barua, stories of persecutions of rival sects by Ashoka appear to be a clear fabrication arising out of sectarian propaganda. At that time, the custom of representing Buddha in human form had not started, and the text conflates Nirgranthas and Ajivikas.

Sri Lanka

Buddhism in Sri Lanka has a unique history and has played an important role in the shaping of Sinhalese nationalist identity. Consequently, politicized Buddhism has contributed to ethnic tensions and protracted social conflict in the island between the majority Sinhalese Buddhist population and other minorities, especially the Tamils.

Three stone statues depicting the Buddha sit in meditative repose. In the background, the wall is adorned with paintings.
Statues of Buddha in Dambulla, Sri Lanka

Violence in Sri Lanka pertaining to Buddhism has been present for decades. This violence originated years ago with the persecution of the Tamil people by the Sinhalese majority. However, after years of discrimination, the Tamil formed the Liberation Tigers of Tamil Eelam (LTTE) which fought for the North-East region of Sri Lanka which would become an independent state for the Tamil population. This civil war continued for three decades and claimed the lives of roughly 40,000 people by the end. The war ended in May 2009 when the majority Sinhalese government killed LTTE leader Velupillai Prabhakaran. After the war, three predominant groups remained in Sri Lanka: the Sinhalese (mostly Buddhist), who accounted for 70% of the population, the Tamils (largely Hindu, with a Christian minority) at 10%, and another 10% who were Muslim. Since Sri Lanka has not stated a national language or religion, Buddhist nationalism began to rise with the fear of Muslims dominating Buddhism. The nationalist organization is called the Bodu Bala Sena (BBS) which is led by Galagoda Aththe Gnanasat.

One of the first major examples of persecution against Muslims was on September 10, 2011 when Buddhist monks destroyed a 300 year old Muslim shrine in Anuradhapura. Although police officers were present during the attack, none intervened.

On April 20, 2012, roughly 2000 Buddhist protested outside a mosque in Dambulla because the building stood on a sacred site for Sri Lankan Buddhists. These protests caused the mosque to cancel prayers due to threats from Buddhist nationalists, but on the following Sunday, Prime Minister D. M. Jayaratne ordered to have the mosque relocated from the sacred site. Since then, the BBS has taken on a new form of persecution by using slogans and propaganda as a way of discriminating against Muslims in Sri Lanka.

With the recent April 2019 Easter bombings orchestrated by Islamic terrorists that claimed the lives of over 250 and injured over 500 Sri Lankans, Muslims in Sri Lanka have faced more danger than ever before from the police and Buddhist nationalists.

Mytho-historical roots

The mytho-historical accounts in the Sinhalese Buddhist national chronicle Mahavamsa ('Great Chronicle'), a non-canonical text written in the sixth century CE by Buddhist monks to glorify Buddhism in Sri Lanka, have been influential in the creation of Sinhalese Buddhist nationalism and militant Buddhism. The Mahavamsa states that Lord Buddha made three visits to Sri Lanka in which he rids the island of forces inimical to Buddhism and instructs deities to protect the ancestors of the Sinhalese (Prince Vijaya and his followers from North India) to enable the establishment and flourishing of Buddhism in Sri Lanka. This myth has led to the widely held Sinhalese Buddhist belief that the country is Sihadipa (island of the Sinhalese) and Dhammadipa (the island ennobled to preserve and propagate Buddhism). In other words, Sinhalese Buddhist nationalists maintain that they are the Buddha's chosen people, and that the island of Sri Lanka is the Buddhist promised land. The Mahavamsa also describes an account of the Buddhist warrior king Dutugamunu, his army, and 500 Buddhist monks battling and defeating the Tamil king Elara, who had come from South India and usurped power in Anuradhapura (the island's capital at the time). When Dutugamunu laments over the thousands he has killed, the eight arhats (Buddha's enlightened disciples) who come to console him reply that no real sin has been committed by him because he has only killed Tamil unbelievers who are no better than beasts, then go on to say: "thou wilt bring glory to the doctrine of the Buddha in manifold ways; therefore cast away care from the heart, O ruler of men". But the casualties mentioned in Mahavamsa is greatly exaggerated.

The Dutugamunu's campaign against king Elara was not to defeat injustice, as the Mahavamsa describes Elara as a good ruler, but to restore Buddhism through a united Sri Lanka under a Buddhist monarch, even by the use of violence. The Mahavamsa story about Buddha's visit to Sri Lanka where he (referred to as the "Conqueror") subdues forces inimical to Buddhism, the Yakkhas (depicted as the non-human inhabitants of the island), by striking "terror to their hearts" and driving them from their homeland, so that his doctrine should eventually "shine in glory", has been described as providing the warrant for the use of violence for the sake of Buddhism and as an account that is in keeping with the general message of the author that the political unity of Sri Lanka under Buddhism requires the removal of uncooperative groups.

According to Neil DeVotta (an Associate Professor of Political Science), the mytho-history described in the Mahavamsa "justifies dehumanizing non-Sinhalese, if doing so is necessary to preserve, protect, and propagate the dhamma (Buddhist doctrine). Furthermore, it legitimizes a just war doctrine, provided that war is waged to protect Buddhism. Together with the Vijaya myth, it introduces the bases for the Sinhalese Buddhist belief that Lord Buddha designated the island of Sri Lanka as a repository for Theravada Buddhism. It claims the Sinhalese were the first humans to inhabit the island (as those who predated the Sinhalese were subhuman) and are thus the true "sons of the soil". Additionally, it institutes the belief that the island's kings were beholden to protect and foster Buddhism. All of these legacies have had ramifications for the trajectory of political Buddhism and Sinhalese Buddhist nationalism."

Among the charges levelled against Magha, the Hindu invader from Kalinga who seized power in Polonnaruwa in the 13th century CE with the help of his soldiers and mercenaries from the modern Kerala and Damila (Tamil Nadu) regions in India, in the Culavamsa was the spreading of false faith. The Pujavaliya composed in the aftermath of Magha's invasion declares that the unbelievers will never have permanent residence on the island reserved for Buddhism and that it is only suitable for Buddhist rulers. But Māgha's rule of 21 years and its aftermath are a watershed in the history of the island, creating a new political order. A second poilitical center emerged in the north of the island where Tamil settlers from previous Indian incursions occupied the Jaffna Peninsula and the Vanni. Many Tamil members of invading armies, mercenaries, joined them rather than returning to India with their compatriots. By the 13th century the Tamils too withdrew from the Vanni almost entirely into the Jaffna peninsula where an independent Tamil kingdom had been established. Māgha, a bigoted Hindu, persecuted Sinhalese Buddhists, despoiling the temples and giving away lands of the Sinhalese to his followers. His priorities in ruling were to extract as much as possible from the land and overturn as many of the traditions of Rajarata as possible. His reign saw the Killing of many Sinhalese by his army and massive migration of the Sinhalese people to the south and west of Sri Lanka, and into the mountainous interior, in a bid to escape his power. The increasing influence of Hinduism on the island starting from the 13th century CE was resisted by the Sangha who decried the worship of Hindu gods and ridiculed Hindu customs such as wearing the sacred ash. However, the Sinhalese kingdoms continued to decline, under the attacks by South Indian states. The last Sinhala king to rule from Polonnaruva was Parākramabāhu III (1302–1310), who was actually a client king of the Pandyas and later had to retreat to Dambadeniya. After this, Sinhala kings were forced to retreat further to the south (to cities like Kurunagala and Gampola), mainly in search of security from South Indian states and from the expansive Tamil kingdom of Jaffna (a Hindu realm which now controlled the north-west of the island).

Rise of modern Sinhalese-Buddhist nationalism

With the rise of modern Sinhalese Buddhist nationalism in the late nineteenth and early twentieth centuries as a reaction to the changes brought under the British colonialism, the old religious mytho-history of the Mahavamsa (especially the emphasis on the Sinhalese and Tamil ethnicities of Duthagamani and Elara, respectively) was revitalized and consequently would prove to be detrimental to the intergroup harmony in the island. As Heather Selma Gregg writes: "Modern-day Sinhalese nationalism, rooted in local myths of being a religiously chosen people and of special progeny, demonstrates that even a religion perceived as inherently peaceful can help fuel violence and hatred in its name."

Buddhist revivalism took place among the Sinhalese to counter Christian missionary influence. The British commissioned the Sinhala translation of the Mahavamsa (which was originally written in Pali), thereby making it accessible to the wider Sinhalese population. During this time the first riot in modern Sri Lankan history broke out in 1883, between Buddhists and Catholics, highlighting the "growing religious divide between the two communities".

The central figure in the formation of modern Sinhalese Buddhist nationalism was the Buddhist revivalist Anagarika Dharmapala (1864–1933), who has been described as "the father of modern Sinhalese Buddhist nationalism". Dharmapala was hostile to all things un-Sinhalese and non-Buddhist. He insisted that the Sinhalese were racially pure and superior Aryans while the Dravidian Tamils were inferior. He popularized the impression that Tamils and Sinhalese had been deadly enemies in Sri Lanka for nearly 2,000 years by quoting the Mahavamsa passages that depicted Tamils as pagan invaders. He characterized the Tamils as "fiercely antagonistic to Buddhism". He also expressed intolerance toward the island's Muslim minorities and other religions in general. Dharmapala also fostered Sinhalese Buddhist nationalism in the spirit of the King Dutthagamani who "rescued Buddhism and our nationalism from oblivion" and stated explicitly that the Island belongs to the Sinhalese Buddhists. Dharmapala has been blamed for laying the groundwork for subsequent Sinhalese Buddhists nationalists to create an ethnocentric state and for hostility to be directed against minorities unwilling to accept such a state.

Politicized Buddhism, the formation of ethnocracy and the civil war

Upon independence, Sinhalese ultra-nationalist Buddhist elites instituted discriminatory policies based on the Buddhist ethno-nationalist ideology of the Mahavamsa, which privileges Sinhalese Buddhist hegemony in the island as Buddha's chosen people for whom the island is a promised land and justifies subjugation of minorities. Some Sinhalese Buddhist officials saw that decreasing Tamil influence was a necessary part of fostering Buddhist cultural renaissance. The Dutthagamani myth was also used to institute Sinhalese Buddhist dominance, with some politicians even identifying with such a mytho-historic hero, and activist monks looked to Dutthagamani as an example to imitate. This principal hero of Mahavamsa became so widely regarded as exemplary by 20th-century Sinhalese Buddhist nationalists because of his defense of Buddhism and the unification of Sri Lanka that journalists started talking about "the Mahavamsa mentality.".

Image of D. S. Senanayake

D. S. Senanayake, who would become Sri Lanka's first prime minister in 1947, reaffirmed in 1939 the common Mahavamsa-based assumption of the Sinhalese Buddhist responsibility for the island's destiny by proclaiming that the Sinhalese Buddhists "are one blood and one nation. We are a chosen people. Buddha said that his religion would last for 5,500 [sic] years. That means that we, as the custodians of that religion, shall last as long." Buddhist monks became increasingly involved in post-independence politics, promoting Sinhalese Buddhist interests at the expense of minorities. Walpola Rahula, Sri Lanka's foremost Buddhist monk scholar and one of the leading proponents of Sinhalese Buddhist nationalism, played a major role in advocating for the involvement of monks in politics, using Buddhist king Dutthagamani's relationship with the sangha to bolster his position. Rahula also argued for a just war doctrine to protect Buddhism by using the example of wars waged by Dutthagamani to restore Buddhism. Rahula maintained that "the entire Sinhalese race was united under the banner of the young Gamini [Dutthagamani]. This was the beginning of nationalism among the Sinhalese. It was a new race with healthy young blood, organized under the new order of Buddhism. A kind of religionationalism, which almost amounted to fanaticism, roused the whole Sinhalese people. A non-Buddhist was not regarded as a human being. Evidently, all Sinhalese, without exception, were Buddhists." In reflecting on Rahula's works, anthropologist H.L. Seneviratne wrote that "it suits Rahula to be an advocate of a Buddhism that glorifies social intercourse with lay society... the receipt of salaries and other forms of material remuneration; ethnic exclusivism and Sinhala Buddhist hegemony; militancy in politics; and violence, war, and the spilling of blood in the name of 'preserving the religion'".

In 1956, the All Ceylon Buddhist Congress (ACBC) released a report titled, "The Betrayal of Buddhism", inquiring into the status of Buddhism in the island. The report argued that Buddhism had been weakened by external threats such as the Tamil invaders mentioned in the Mahavamsa and later Western colonial powers. It also demanded the state to restore and foster Buddhism and to give preferential treatment to Buddhist schools. The same year, S. W. R. D. Bandaranaike capitalized on the ACBC report and its recommendations as the foundation for his election campaign, using it as the 'blueprint for a broad spectrum of policy', which included introducing Sinhala as the sole official language of the state. With the help of significant number of Buddhist monks and various Sinhalese Buddhist organizations, Bandaranaike became prime minister after winning the 1956 elections. Bandaranaike had also campaigned on the basis of Sinhalese Buddhist nationalism, drawing influences from the writings of Dharmapala and the Mahavamsa, arguing that it was the duty of the government to preserve the Sinhalese Buddhist nature of the island's destiny. Once in power, Bandaranaike implemented the 1956 Sinhala Only Act, which would make Sinhala the country's official language and hence all official state transactions would be conducted in Sinhala. This put non-Sinhala speakers at a disadvantage for employment and educational opportunities. As a result, Tamils protested the policy by staging sit-ins, which in turn prompted counterdemonstrations by extremist Buddhist monks, later degenerating into anti-Tamil riots in which more than one hundred people were injured and Tamil businesses were looted. Riots then spread throughout the country, killing hundreds of people. Bandaranaike tried to mitigate tensions over the language policy by proposing a compromise with the Tamil leaders, resulting in a 1957 pact that would allow the use of Tamil as an administrative language along with Sinhala and greater political autonomy for Tamils. Ultra-nationalist Buddhist monks and other Sinhalese nationalists opposed this pact by staging mass demonstrations and hunger strikes. In an editorial in the same year, a monk asked Bandaranaike to read the Mahavamsa and to heed its lessons: "[Dutthagamani] conquered by the sword and united the land [Sri Lanka] without dividing it among our enemies [i.e. the Tamils] and established Sinhala and Buddhism as the state language and religion." In the late 1950s, it had become common for politicians and monks to exploit the Mahavamsa narrative of Dutthagamani to oppose any concession to the Tamil minorities.

With nationalist Buddhist monks playing a major role in exerting pressure to abrogate the pact, Bandaranaike acceded to their demands on April 9, 1958 by tearing up "a copy of the pact in front of the assembled monks who clapped in joy". Soon after the pact was abrogated, another series of anti-Tamil riots spread throughout the country, which left hundreds dead and thousands displaced. Preceding the 1958 riots, rhetoric of monks contributed to the perception of Tamils being the enemies of the country and of Buddhism. Both extremist Buddhist monks and laity laid the foundation for the justifiable use of force against Tamils in response to their demand for greater autonomy by arguing that the whole of Sri Lanka was a promised land of the Sinhalese Buddhists and it was the role of the monks to defend a united Sri Lanka. Tamils were also portrayed as threatening interlopers, compared to the Mahavamsa account of the usurper Tamil king Elara. Monks and politicians invoked the story of the Buddhist warrior king Dutthagamani to urge the Sinhalese to fight against Tamils and their claims to the island, thereby providing justification for violence against Tamils. As Tessa J. Bartholomeusz explained: "Tamil claims to a homeland were met with an ideology, linked to a Buddhist story, that legitimated war with just cause: the protection of Sri Lanka for the Sinhala-Buddhist people." In order to appease Tamils amidst the ethnic tension, Bandaranaike modified the Sinhala Only Act to allow Tamil to be used in education and government in Tamil areas, and as a result an extreme ultra-nationalist Buddhist monk named Talduwe Somarama assassinated him on September 26, 1959. The monk claimed he carried out the assassination "for the greater good of his country, race and religion". It has also been suggested that the monk was guided in part by reading of the Mahavamsa.

Successive governments after Bandaranaike implemented a similar Sinhalese Buddhist nationalist agenda, at the expense of minorities. In 1972, the government rewrote its constitution and gave Buddhism "the foremost place [in the Republic of Sri Lanka]" and making it "the duty of the state to protect and foster Buddhism". With another pact in 1965 that sought to establish greater regional autonomy for Tamils being abrogated (some members of the Buddhist clergy were at the forefront in opposing the pact) and the implementation of discriminatory quota system in 1974 that severely restricted Tamil entrance to universities, Tamil youth became radicalized, calling for an independent homeland to be established in the Tamil-dominated northeastern region of the island. In 1977, anti-Tamil riots spread throughout the country, killing hundreds of Tamils and leaving thousands homeless. A leading monk claimed that one of the reasons for the anti-Tamil riots of 1977 was the Tamil demonization of the Sinhalese Buddhist epic hero Dutthagamani, which resulted in a justified retaliation. Another anti-Tamil riot erupted in 1981 in Jaffna, where Sinhalese police and paramilitaries destroyed statues of Tamil cultural and religious figures; looted and torched a Hindu temple and Tamil-owned shops and homes; killed four Tamils; and torched the Jaffna Public Library which was of great cultural significance to Tamils. In response to the militant separatist Tamil group LTTE killing 13 Sinhalese soldiers, the largest anti-Tamil pogrom occurred in 1983, leaving between 2,000 and 3,000 of Tamils killed and forcing from 70,000 to 100,000 Tamils into refugee camps, eventually propelling the country into a civil war between the LTTE and the predominately Sinhalese Buddhist Sri Lankan government. In the 1983 anti-Tamil pogrom, Buddhist monks lead rioters in some instance. Cyril Mathew, a Senior Minister in President Jayawardene's Cabinet and a Sinhalese Buddhist nationalist who in the year preceding the pogrom reaffirmed the special relationship between Buddhism and Sinhalese and the Buddhist nature of the country, was also responsible for the pogrom. In the months following the anti-Tamil pogrom, authorizations for violence against Tamils began to appear in the press, with Tamils being depicted as interlopers on Dhammadipa. The Mahavamsa narrative of Dutthagamani and Elara was also invoked to justify violence against Tamils. The aftermath of the pogrom spawned debates over the rights to the island with the "sons of the soil" ideology being called into prominence. A government agent declared that Sri Lanka's manifest destiny "was to uphold the pristine doctrine of Theravada Buddhism". This implied that Sinhalese Buddhists had a sacred claim to Sri Lanka, while the Tamils did not, a claim which might call for violence. The Sinhalese Buddhists, including the Sri Lankan government, resisted the Tamil claim to a separate homeland of their own as the Sinhalese Buddhists maintained that the entire country belonged to them. Another government agent linked the then Prime Minister Jayewardene's attempts to thwart the emergence of a Tamil homeland to Dutthagamani's victory over Elara and went on to say, "[w]e will never allow the country to be divided", thereby justifying violence against Tamils.

In the context of increasing Tamil militant struggle for separatism, militant Buddhist monks founded the Mavbima Surakime Vyaparaya (MSV) or "Movement for the Protection of the Motherland" in 1986 which sought to work with political parties "to maintain territorial unity of Sri Lanka and Sinhalese Buddhist sovereignty over the island". The MSV used the Mahavamsa to justify its goals, which included the usage of force to fight against the Tamil threat and defend the Buddhist state. In 1987, along with the MSV, the Janatha Vimukthi Peramuna (JVP, a militant Sinhalese nationalist group which included monks) took up arms to protest the signing of the Indo-Sri Lanka Accord which sought to establish peace in Sri Lanka by requiring the Sri Lankan government to make a number of concessions to Tamil demands, including devolution of power to Tamil provinces. The JVP, with the support of parts of the Sangha, launched a campaign of violent insurrection against the government to oppose the accord as the Sinhalese nationalists believed it would compromise the sovereignty of Sri Lanka.

From the beginning of the civil war in 1983 to the end of it in 2009, militant Buddhist monks were involved in politics and opposed negotiations, ceasefire agreements, or any devolution of power to Tamil minorities, and most supported military solution to the conflict. This has led to Asanga Tilakaratne, head of the Department of Buddhist Philosophy in the Postgraduate Institute of Pali and Buddhist Studies in Colombo, to remark that "the Sinhala Buddhist nationalists are ... opposed to any attempt to solve the ethnic problem by peaceful means; and they call for a 'holy war' against Tamils". It has been argued that the absence of opportunities for power sharing among the different ethnic groups in the island "has been one of the primary factors behind the intensification of the conflict". Numerous nationalist Buddhist religious leaders and extremist Buddhist organizations since the country's independence have played a role in mobilizing against the devolution of power to the Tamils. Leading Buddhist monks opposed devolution of power that would grant regional autonomy to Tamils on the basis of Mahavamsa worldview that the entire country is a Buddhist promised land which belongs to the Sinhalese Buddhist people, along with the fear that devolution would eventually lead to separate country.

The two major contemporary political parties to advocate for Sinhalese Buddhist nationalism are the JVP and the Jathika Hela Urumaya (JHU) or "National Heritage Party", the latter of which is composed solely of nationalist Buddhist monks. According to A. R. M. Imtiyaz, these groups share common goals: "to uphold Buddhism and establish a link between the state and religion, and to advocate a violent solution to the Tamil question and oppose all form of devolution to the minorities, particularly the Tamils". The JHU, in shunning non-violent solutions to the ethnic conflict, urged young Sinhalese Buddhists to sign up for the army, with as many as 30,000 Sinhalese young men doing just that. One JHU leader even declared that NGOs and certain government servants were traitors and they should be set on fire and burnt due to their opposition to a military solution to the civil war. The international community encouraged a federal structure for Sri Lanka as a peaceful solution to the civil war but any form of Tamil self-determination, even the more limited measure of autonomy, was strongly opposed by hard-line Sinhalese Buddhist nationalist groups such as the JVP and JHU, who pushed for the military solution. These groups in their hard-line support for a military solution to the conflict, without any regard for the plight of innocent Tamil civilians, have opposed negotiated settlement, ceasefire agreement, demanded that the Norwegians be removed as peace facilitators, demanded the war to be prosecuted more forcefully and exerted influence in the Rajapaksa government (which they helped to elect), resulting in the brutal military defeat of the LTTE with heavy civilian casualties. The nationalist monks' support of the government's military offense against the LTTE gave "religious legitimacy to the state's claim of protecting the island for the Sinhalese Buddhist majority." President Rajapaksa, in his war against the LTTE, has been compared to the Buddhist king Dutthagamani by the Sinhalese Buddhist nationalists.

Violence against religious minorities

Other minority groups have also come under attack by Sinhalese Buddhist nationalists. Fear of country's Buddhist hegemony being challenged by Christian proselytism has driven extremist Buddhist monks and organizations to demonize Christian organizations, with one popular monk comparing missionary activity to terrorism; as a result, Sinhalese Buddhist nationalists, including the JVP and JHU, who oppose attempts to convert Buddhists to another religion, support or conduct anti-Christian violence. The number of attacks against Christian churches rose from 14 in 2000 to over 100 in 2003. Dozens of these acts were confirmed by U.S. diplomatic observers. This anti-Christian violence was led by extremist Buddhist clergy and has included acts of "beatings, arson, acts of sacrilege, death threats, violent disruption of worship, stoning, abuse, unlawful restraint, and even interference with funerals". It has been noted that the strongest anti-West sentiments accompany the anti-Christian violence since the Sinhalese Buddhist nationalists identify Christianity with the West which they think is conspiring to undermine Buddhism.

In the postwar Sri Lanka, ethnic and religious minorities continue to face threat from Sinhalese Buddhist nationalism. There have been continued sporadic attacks on Christian churches by Buddhist extremists who allege that Christians conduct unethical or forced conversion. The Pew Research Center has listed Sri Lanka among the countries with very high religious hostilities in 2012 due to the violence committed by Buddhist monks against Muslim and Christian places of worship. These acts included attacking a mosque and forcefully taking over a Seventh-day advent church and converting it into a Buddhist temple.

Extremist Buddhist leaders justify their attacks on the places of worship of minorities by arguing that Sri Lanka is the promised land of the Sinhalese Buddhists to safeguard Buddhism. The recently formed Buddhist extremist group, the Bodu Bala Sena (BBS), or Buddhist Power Force, founded by extreme Buddhist monks in 2012, has been accused of inciting the anti-Muslim riots that killed 4 Muslims and injured 80 in 2014. The leader of the BBS, in linking the government's military victory over the LTTE to the ancient Buddhist king conquest of Tamil king Elara, said that Tamils have been taught a lesson twice and warned other minorities of the same fate if they tried to challenge Sinhalese Buddhist culture. The BBS has been compared to the Taliban, accused of spreading extremism and communal hatred against Muslims and has been described as an "ethno-religious fascist movement". Extremist Buddhist monks have also protested against UN Human Rights Council resolution that called for an inquiry into humanitarian abuses and possible war crimes during the civil war. The BBS has received criticism and opposition from other Buddhist clergy and politicians. Mangala Samaraweera, a Sri Lankan Theravada Buddhist politician who has served as Minister of Foreign Affairs since 2015, has accused the BBS of being "a representation of 'Taliban' terrorism" and of spreading extremism and communal hatred against Muslims. Samaraweera has also alleged that the BBS is secretly funded by the Ministry of Defence. Anunayake Bellanwila Wimalaratana, deputy incumbent of Bellanwila Rajamaha Viharaya and President of the Bellanwila Community Development Foundation, has stated that "The views of the Bodu Bala Sena are not the views of the entire Sangha community" and that "We don't use our fists to solve problems, we use our brains". Wataraka Vijitha Thero, a Buddhist monk who condemns violence against Muslims and heavily criticized the BBS and the government, has been attacked and tortured for his stances.

Buddhist opposition to Sinhala Buddhist nationalism

Sinhala Buddhist Nationalism is opposed to Sarvodaya, although they share many of the same influences like Dharmapāla's teachings for example, by having a focus upon Sinhalese culture and ethnicity sanctioning the use of violence in defence of dhamma, while Sarvodaya has emphasized the application of Buddhist values in order to transform society and campaigning for peace.

These Buddhist nationalists have been opposed by the Sarvodaya Shramadana Movement, a self-governance movement led by the Buddhist Dr. A. T. Ariyaratne and based in Buddhist ideals, who condemn the use of violence and the denial of human rights to Tamils and other non-Buddhists. Ariyaratne calls for non-violent action and he has been actively working for peace in Sri Lanka for many decades, and has stated that the only way to peace is through "the dispelling of the view of 'I and mine' or the shedding of 'self' and the realization of the true doctrines of the interconnection between all animal species and the unity of all humanity", thus advocating social action in Buddhist terms. He stated in one of his lectures, "When we work towards the welfare of all the means we use have to be based on Truth, Non-violence and Selflessness in conformity with Awakening of All". What Ariyaratne advocates is losing the self in the service of others and attempting to bring others to awakening. Ariyaratne has stated, "I cannot awaken myself unless I help awaken others".

East Asia

Japan

Kasumigaseki Station in Japan, one of the many stations affected during the attack by the Aum Shinrikyo cult

The beginning of "Buddhist violence" in Japan relates to a long history of feuds among Buddhists. The sōhei or "warrior monks" appeared during the Heian period, although the seeming contradiction in being a Buddhist "warrior monk" caused controversy even at the time. More directly linked is that the Ikkō-shū movement was considered an inspiration to Buddhists in the Ikkō-ikki rebellion. In Osaka they defended their temple with the slogan "The mercy of Buddha should be recompensed even by pounding flesh to pieces. One's obligation to the Teacher should be recompensed even by smashing bones to bits!"

During World War II, Japanese Buddhist literature from that time, as part of its support of the Japanese war effort, stated "In order to establish eternal peace in East Asia, arousing the great benevolence and compassion of Buddhism, we are sometimes accepting and sometimes forceful. We now have no choice but to exercise the benevolent forcefulness of 'killing one in order that many may live' (issatsu tashō). This is something which Mahayana Buddhism approves of only with the greatest of seriousness..." Almost all Japanese Buddhists temples strongly supported Japan's militarization. These were heavily criticized by the Chinese Buddhists of the era, who disputed the validity of the statements made by those Japanese Buddhist supporters of the war. In response the Japanese Pan-Buddhist Society (Myowa Kai) rejected the criticism and stated that "We now have no choice but to exercise the benevolent forcefulness of 'killing one in order that many may live' (issatsu tashō)" and that the war was absolutely necessary to implement the dharma in Asia. The society re-examined more than 70 texts written by Nichiren and re-edited his writings, making changes in 208 places, cutting all the statements that disagreed with the state Shinto. In contrast, a few Japanese Buddhists such as Ichikawa Haku and Seno'o Girō opposed this and were targeted. During the 1940s, "leaders of the Honmon Hokkeshu and Soka Kyoiku Gakkai were imprisoned for their defiance of wartime government religious policy, which mandated display of reverence for the state Shinto". Brian Daizen Victoria, a Buddhist priest in the Sōtō Zen sect, documented in his book Zen at War how Buddhist institutions justified Japanese militarism in official publications and cooperated with the Imperial Japanese Army in the Russo-Japanese War and World War II. In response to the book, several sects issued an apology for their wartime support of the government.

In more modern times instances of Buddhist-inspired terrorism or militarism have occurred in Japan, such as the assassinations of the League of Blood Incident led by Nissho Inoue, a Nichirenist or fascist-nationalist who preached a self-styled Nichiren Buddhism.

Aum Shinrikyo, the Japanese new religion and doomsday cult that was the cause of the Tokyo subway sarin attack that killed thirteen people and injured more than a thousand, drew upon a syncretic view of idiosyncratic interpretations of elements of early Indian Buddhism, Tibetan Buddhism and Hinduism, taking Shiva as the main image of worship, Christian millennialist ideas from the Book of Revelation, Yoga and the writings of Nostradamus. Its founder, Chizuo Matsumoto, claimed that he sought to restore "original Buddhism" and declared himself "Christ", Japan's only fully enlightened master and identified with the "Lamb of God". His purported mission was to take upon himself the sins of the world, and he claimed he could transfer to his followers spiritual power and ultimately take away their sins and bad deeds. While many discount Aum Shinrikyo's Buddhist characteristics and affiliation to Buddhism, scholars often refer to it as an offshoot of Japanese Buddhism, and this was how the movement generally defined and saw itself.

North Asia

Russia

In 2022, Khambo Lama Damba Ayusheev, the head of the Buddhist Traditional Sangha of Russia (BTSR), the largest Buddhist denomination in Russia, voiced support for the Russian invasion of Ukraine.

Distributed computing

From Wikipedia, the free encyclopedia

Distributed computing is a field of computer science that studies distributed systems, defined as computer systems whose inter-communicating components are located on different networked computers.

The components of a distributed system communicate and coordinate their actions by passing messages to one another in order to achieve a common goal. Three significant challenges of distributed systems are: maintaining concurrency of components, overcoming the lack of a global clock, and managing the independent failure of components. When a component of one system fails, the entire system does not fail. Examples of distributed systems vary from SOA-based systems to microservices to massively multiplayer online games to peer-to-peer applications. Distributed systems cost significantly more than monolithic architectures, primarily due to increased needs for additional hardware, servers, gateways, firewalls, new subnets, proxies, and so on. Also, distributed systems are prone to fallacies of distributed computing. On the other hand, a well designed distributed system is more scalable, more durable, more changeable and more fine-tuned than a monolithic application deployed on a single machine. According to Marc Brooker: "a system is scalable in the range where marginal cost of additional workload is nearly constant." Serverless technologies fit this definition but the total cost of ownership, and not just the infra cost must be considered.

A computer program that runs within a distributed system is called a distributed program, and distributed programming is the process of writing such programs. There are many different types of implementations for the message passing mechanism, including pure HTTP, RPC-like connectors and message queues.

Distributed computing also refers to the use of distributed systems to solve computational problems. In distributed computing, a problem is divided into many tasks, each of which is solved by one or more computers, which communicate with each other via message passing.

Introduction

The word distributed in terms such as "distributed system", "distributed programming", and "distributed algorithm" originally referred to computer networks where individual computers were physically distributed within some geographical area. The terms are nowadays used in a much wider sense, even referring to autonomous processes that run on the same physical computer and interact with each other by message passing.

While there is no single definition of a distributed system, the following defining properties are commonly used as:

  • There are several autonomous computational entities (computers or nodes), each of which has its own local memory.
  • The entities communicate with each other by message passing.

A distributed system may have a common goal, such as solving a large computational problem; the user then perceives the collection of autonomous processors as a unit. Alternatively, each computer may have its own user with individual needs, and the purpose of the distributed system is to coordinate the use of shared resources or provide communication services to the users.

Other typical properties of distributed systems include the following:

  • The system has to tolerate failures in individual computers.
  • The structure of the system (network topology, network latency, number of computers) is not known in advance, the system may consist of different kinds of computers and network links, and the system may change during the execution of a distributed program.
  • Each computer has only a limited, incomplete view of the system. Each computer may know only one part of the input.

Patterns

Here are common architectural patterns used for distributed computing:

Events vs. Messages

In distributed systems, events represent a fact or state change (e.g., OrderPlaced) and are typically broadcast asynchronously to multiple consumers, promoting loose coupling and scalability. While events generally don’t expect an immediate response, acknowledgment mechanisms are often implemented at the infrastructure level (e.g., Kafka commit offsets, SNS delivery statuses) rather than being an inherent part of the event pattern itself.

In contrast, messages serve a broader role, encompassing commands (e.g., ProcessPayment), events (e.g., PaymentProcessed), and documents (e.g., DataPayload). Both events and messages can support various delivery guarantees, including at-least-once, at-most-once, and exactly-once, depending on the technology stack and implementation. However, exactly-once delivery is often achieved through idempotency mechanisms rather than true, infrastructure-level exactly-once semantics.

Delivery patterns for both events and messages include publish/subscribe (one-to-many) and point-to-point (one-to-one). While request/reply is technically possible, it is more commonly associated with messaging patterns rather than pure event-driven systems. Events excel at state propagation and decoupled notifications, while messages are better suited for command execution, workflow orchestration, and explicit coordination.

Modern architectures commonly combine both approaches, leveraging events for distributed state change notifications and messages for targeted command execution and structured workflows based on specific timing, ordering, and delivery requirements.

Parallel and distributed computing

(a), (b): a distributed system.
(c): a parallel system.

Distributed systems are groups of networked computers which share a common goal for their work. The terms "concurrent computing", "parallel computing", and "distributed computing" have much overlap, and no clear distinction exists between them. The same system may be characterized both as "parallel" and "distributed"; the processors in a typical distributed system run concurrently in parallel. Parallel computing may be seen as a particularly tightly coupled form of distributed computing, and distributed computing may be seen as a loosely coupled form of parallel computing. Nevertheless, it is possible to roughly classify concurrent systems as "parallel" or "distributed" using the following criteria:

  • In parallel computing, all processors may have access to a shared memory to exchange information between processors.
  • In distributed computing, each processor has its own private memory (distributed memory). Information is exchanged by passing messages between the processors.

The figure on the right illustrates the difference between distributed and parallel systems. Figure (a) is a schematic view of a typical distributed system; the system is represented as a network topology in which each node is a computer and each line connecting the nodes is a communication link. Figure (b) shows the same distributed system in more detail: each computer has its own local memory, and information can be exchanged only by passing messages from one node to another by using the available communication links. Figure (c) shows a parallel system in which each processor has a direct access to a shared memory.

The situation is further complicated by the traditional uses of the terms parallel and distributed algorithm that do not quite match the above definitions of parallel and distributed systems (see below for more detailed discussion). Nevertheless, as a rule of thumb, high-performance parallel computation in a shared-memory multiprocessor uses parallel algorithms while the coordination of a large-scale distributed system uses distributed algorithms.

History

The use of concurrent processes which communicate through message-passing has its roots in operating system architectures studied in the 1960s. The first widespread distributed systems were local-area networks such as Ethernet, which was invented in the 1970s.

ARPANET, one of the predecessors of the Internet, was introduced in the late 1960s, and ARPANET e-mail was invented in the early 1970s. E-mail became the most successful application of ARPANET, and it is probably the earliest example of a large-scale distributed application. In addition to ARPANET (and its successor, the global Internet), other early worldwide computer networks included Usenet and FidoNet from the 1980s, both of which were used to support distributed discussion systems.

The study of distributed computing became its own branch of computer science in the late 1970s and early 1980s. The first conference in the field, Symposium on Principles of Distributed Computing (PODC), dates back to 1982, and its counterpart International Symposium on Distributed Computing (DISC) was first held in Ottawa in 1985 as the International Workshop on Distributed Algorithms on Graphs.

Architectures

Various hardware and software architectures are used for distributed computing. At a lower level, it is necessary to interconnect multiple CPUs with some sort of network, regardless of whether that network is printed onto a circuit board or made up of loosely coupled devices and cables. At a higher level, it is necessary to interconnect processes running on those CPUs with some sort of communication system.

Whether these CPUs share resources or not determines a first distinction between three types of architecture:

Distributed programming typically falls into one of several basic architectures: client–server, three-tier, n-tier, or peer-to-peer; or categories: loose coupling, or tight coupling.

  • Client–server: architectures where smart clients contact the server for data then format and display it to the users. Input at the client is committed back to the server when it represents a permanent change.
  • Three-tier: architectures that move the client intelligence to a middle tier so that stateless clients can be used. This simplifies application deployment. Most web applications are three-tier.
  • n-tier: architectures that refer typically to web applications which further forward their requests to other enterprise services. This type of application is the one most responsible for the success of application servers.
  • Peer-to-peer: architectures where there are no special machines that provide a service or manage the network resources. Instead all responsibilities are uniformly divided among all machines, known as peers. Peers can serve both as clients and as servers. Examples of this architecture include BitTorrent and the bitcoin network.

Another basic aspect of distributed computing architecture is the method of communicating and coordinating work among concurrent processes. Through various message passing protocols, processes may communicate directly with one another, typically in a main/sub relationship. Alternatively, a "database-centric" architecture can enable distributed computing to be done without any form of direct inter-process communication, by utilizing a shared database. Database-centric architecture in particular provides relational processing analytics in a schematic architecture allowing for live environment relay. This enables distributed computing functions both within and beyond the parameters of a networked database.

Cell-Based Architecture

Cell-based architecture is a distributed computing approach in which computational resources are organized into self-contained units called cells. Each cell operates independently, processing requests while maintaining scalability, fault isolation, and availability.

A cell typically consists of multiple services or application components and functions as an autonomous unit. Some implementations replicate entire sets of services across multiple cells, while others partition workloads between cells. In replicated models, requests may be rerouted to an operational cell if another experiences a failure. This design is intended to enhance system resilience by reducing the impact of localized failures.

Some implementations employ circuit breakers within and between cells. Within a cell, circuit breakers may be used to prevent cascading failures among services, while inter-cell circuit breakers can isolate failing cells and redirect traffic to those that remain operational.

Cell-based architecture has been adopted in some large-scale distributed systems, particularly in cloud-native and high-availability environments, where fault isolation and redundancy are key design considerations. Its implementation varies depending on system requirements, infrastructure constraints, and operational objectives.

Applications

Reasons for using distributed systems and distributed computing may include:

  • The very nature of an application may require the use of a communication network that connects several computers: for example, data produced in one physical location and required in another location.
  • There are many cases in which the use of a single computer would be possible in principle, but the use of a distributed system is beneficial for practical reasons. For example:
    • It can allow for much larger storage and memory, faster compute, and higher bandwidth than a single machine.
    • It can provide more reliability than a non-distributed system, as there is no single point of failure. Moreover, a distributed system may be easier to expand and manage than a monolithic uniprocessor system.
    • It may be more cost-efficient to obtain the desired level of performance by using a cluster of several low-end computers, in comparison with a single high-end computer.

Examples

Examples of distributed systems and applications of distributed computing include the following:

Reactive distributed systems

According to Reactive Manifesto, reactive distributed systems are responsive, resilient, elastic and message-driven. Subsequently, Reactive systems are more flexible, loosely-coupled and scalable. To make your systems reactive, you are advised to implement Reactive Principles. Reactive Principles are a set of principles and patterns which help to make your cloud native application as well as edge native applications more reactive.

Theoretical foundations

Models

Many tasks that we would like to automate by using a computer are of question–answer type: we would like to ask a question and the computer should produce an answer. In theoretical computer science, such tasks are called computational problems. Formally, a computational problem consists of instances together with a solution for each instance. Instances are questions that we can ask, and solutions are desired answers to these questions.

Theoretical computer science seeks to understand which computational problems can be solved by using a computer (computability theory) and how efficiently (computational complexity theory). Traditionally, it is said that a problem can be solved by using a computer if we can design an algorithm that produces a correct solution for any given instance. Such an algorithm can be implemented as a computer program that runs on a general-purpose computer: the program reads a problem instance from input, performs some computation, and produces the solution as output. Formalisms such as random-access machines or universal Turing machines can be used as abstract models of a sequential general-purpose computer executing such an algorithm.

The field of concurrent and distributed computing studies similar questions in the case of either multiple computers, or a computer that executes a network of interacting processes: which computational problems can be solved in such a network and how efficiently? However, it is not at all obvious what is meant by "solving a problem" in the case of a concurrent or distributed system: for example, what is the task of the algorithm designer, and what is the concurrent or distributed equivalent of a sequential general-purpose computer?

The discussion below focuses on the case of multiple computers, although many of the issues are the same for concurrent processes running on a single computer.

Three viewpoints are commonly used:

Parallel algorithms in shared-memory model
  • All processors have access to a shared memory. The algorithm designer chooses the program executed by each processor.
  • One theoretical model is the parallel random-access machines (PRAM) that are used. However, the classical PRAM model assumes synchronous access to the shared memory.
  • Shared-memory programs can be extended to distributed systems if the underlying operating system encapsulates the communication between nodes and virtually unifies the memory across all individual systems.
  • A model that is closer to the behavior of real-world multiprocessor machines and takes into account the use of machine instructions, such as Compare-and-swap (CAS), is that of asynchronous shared memory. There is a wide body of work on this model, a summary of which can be found in the literature.
Parallel algorithms in message-passing model
  • The algorithm designer chooses the structure of the network, as well as the program executed by each computer.
  • Models such as Boolean circuits and sorting networks are used. A Boolean circuit can be seen as a computer network: each gate is a computer that runs an extremely simple computer program. Similarly, a sorting network can be seen as a computer network: each comparator is a computer.
Distributed algorithms in message-passing model
  • The algorithm designer only chooses the computer program. All computers run the same program. The system must work correctly regardless of the structure of the network.
  • A commonly used model is a graph with one finite-state machine per node.

In the case of distributed algorithms, computational problems are typically related to graphs. Often the graph that describes the structure of the computer network is the problem instance. This is illustrated in the following example.

An example

Consider the computational problem of finding a coloring of a given graph G. Different fields might take the following approaches:

Centralized algorithms
  • The graph G is encoded as a string, and the string is given as input to a computer. The computer program finds a coloring of the graph, encodes the coloring as a string, and outputs the result.
Parallel algorithms
  • Again, the graph G is encoded as a string. However, multiple computers can access the same string in parallel. Each computer might focus on one part of the graph and produce a coloring for that part.
  • The main focus is on high-performance computation that exploits the processing power of multiple computers in parallel.
Distributed algorithms
  • The graph G is the structure of the computer network. There is one computer for each node of G and one communication link for each edge of G. Initially, each computer only knows about its immediate neighbors in the graph G; the computers must exchange messages with each other to discover more about the structure of G. Each computer must produce its own color as output.
  • The main focus is on coordinating the operation of an arbitrary distributed system.

While the field of parallel algorithms has a different focus than the field of distributed algorithms, there is much interaction between the two fields. For example, the Cole–Vishkin algorithm for graph coloring was originally presented as a parallel algorithm, but the same technique can also be used directly as a distributed algorithm.

Moreover, a parallel algorithm can be implemented either in a parallel system (using shared memory) or in a distributed system (using message passing). The traditional boundary between parallel and distributed algorithms (choose a suitable network vs. run in any given network) does not lie in the same place as the boundary between parallel and distributed systems (shared memory vs. message passing).

Complexity measures

In parallel algorithms, yet another resource in addition to time and space is the number of computers. Indeed, often there is a trade-off between the running time and the number of computers: the problem can be solved faster if there are more computers running in parallel (see speedup). If a decision problem can be solved in polylogarithmic time by using a polynomial number of processors, then the problem is said to be in the class NC. The class NC can be defined equally well by using the PRAM formalism or Boolean circuits—PRAM machines can simulate Boolean circuits efficiently and vice versa.

In the analysis of distributed algorithms, more attention is usually paid on communication operations than computational steps. Perhaps the simplest model of distributed computing is a synchronous system where all nodes operate in a lockstep fashion. This model is commonly known as the LOCAL model. During each communication round, all nodes in parallel (1) receive the latest messages from their neighbours, (2) perform arbitrary local computation, and (3) send new messages to their neighbors. In such systems, a central complexity measure is the number of synchronous communication rounds required to complete the task.

This complexity measure is closely related to the diameter of the network. Let D be the diameter of the network. On the one hand, any computable problem can be solved trivially in a synchronous distributed system in approximately 2D communication rounds: simply gather all information in one location (D rounds), solve the problem, and inform each node about the solution (D rounds).

On the other hand, if the running time of the algorithm is much smaller than D communication rounds, then the nodes in the network must produce their output without having the possibility to obtain information about distant parts of the network. In other words, the nodes must make globally consistent decisions based on information that is available in their local D-neighbourhood. Many distributed algorithms are known with the running time much smaller than D rounds, and understanding which problems can be solved by such algorithms is one of the central research questions of the field. Typically an algorithm which solves a problem in polylogarithmic time in the network size is considered efficient in this model.

Another commonly used measure is the total number of bits transmitted in the network (cf. communication complexity). The features of this concept are typically captured with the CONGEST(B) model, which is similarly defined as the LOCAL model, but where single messages can only contain B bits.

Other problems

Traditional computational problems take the perspective that the user asks a question, a computer (or a distributed system) processes the question, then produces an answer and stops. However, there are also problems where the system is required not to stop, including the dining philosophers problem and other similar mutual exclusion problems. In these problems, the distributed system is supposed to continuously coordinate the use of shared resources so that no conflicts or deadlocks occur.

There are also fundamental challenges that are unique to distributed computing, for example those related to fault-tolerance. Examples of related problems include consensus problemsByzantine fault tolerance, and self-stabilisation.

Much research is also focused on understanding the asynchronous nature of distributed systems:

Note that in distributed systems, latency should be measured through "99th percentile" because "median" and "average" can be misleading.

Coordinator election (or leader election) is the process of designating a single process as the organizer of some task distributed among several computers (nodes). Before the task is begun, all network nodes are either unaware which node will serve as the "coordinator" (or leader) of the task, or unable to communicate with the current coordinator. After a coordinator election algorithm has been run, however, each node throughout the network recognizes a particular, unique node as the task coordinator.

The network nodes communicate among themselves in order to decide which of them will get into the "coordinator" state. For that, they need some method in order to break the symmetry among them. For example, if each node has unique and comparable identities, then the nodes can compare their identities, and decide that the node with the highest identity is the coordinator.

The definition of this problem is often attributed to LeLann, who formalized it as a method to create a new token in a token ring network in which the token has been lost.

Coordinator election algorithms are designed to be economical in terms of total bytes transmitted, and time. The algorithm suggested by Gallager, Humblet, and Spira for general undirected graphs has had a strong impact on the design of distributed algorithms in general, and won the Dijkstra Prize for an influential paper in distributed computing.

Many other algorithms were suggested for different kinds of network graphs, such as undirected rings, unidirectional rings, complete graphs, grids, directed Euler graphs, and others. A general method that decouples the issue of the graph family from the design of the coordinator election algorithm was suggested by Korach, Kutten, and Moran.

In order to perform coordination, distributed systems employ the concept of coordinators. The coordinator election problem is to choose a process from among a group of processes on different processors in a distributed system to act as the central coordinator. Several central coordinator election algorithms exist.

Properties of distributed systems

So far the focus has been on designing a distributed system that solves a given problem. A complementary research problem is studying the properties of a given distributed system.

The halting problem is an analogous example from the field of centralised computation: we are given a computer program and the task is to decide whether it halts or runs forever. The halting problem is undecidable in the general case, and naturally understanding the behaviour of a computer network is at least as hard as understanding the behaviour of one computer.

However, there are many interesting special cases that are decidable. In particular, it is possible to reason about the behaviour of a network of finite-state machines. One example is telling whether a given network of interacting (asynchronous and non-deterministic) finite-state machines can reach a deadlock. This problem is PSPACE-complete, i.e., it is decidable, but not likely that there is an efficient (centralised, parallel or distributed) algorithm that solves the problem in the case of large networks.

Much Ado About Nothing

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