https://en.wikipedia.org/wiki/Chess_strategy
Chess strategy is the aspect of chess playing concerned with evaluation of chess positions and setting of goals and long-term plans for future play. While evaluating a position strategically, a player must take into account such factors as the relative value of the pieces on the board, pawn structure, king safety, position of pieces, and control of key squares and groups of squares (e.g. diagonals, open files, and individual squares). Chess strategy is distinguished from chess tactics, which is the aspect of play concerned with the move-by-move setting up of threats and defenses. Some authors distinguish static strategic imbalances (e.g. having more valuable pieces or better pawn structure), which tend to persist for many moves, from dynamic imbalances (such as one player having an advantage in piece development), which are temporary. This distinction affects the immediacy with which a sought-after plan should take effect. Until players reach the skill level of "master", chess tactics tend to ultimately decide the outcomes of games more often than strategy does. Many chess coaches thus emphasize the study of tactics as the most efficient way to improve one's results in serious chess play.
The most basic way to evaluate one's position is to count the total value of pieces on both sides. The point values used for this purpose are based on experience. Usually pawns are considered to be worth one point, knights and bishops three points each, rooks five points, and queens nine points. The fighting value of the king in the endgame is approximately four points. These basic values are modified by other factors such as the position of the pieces (e.g. advanced pawns are usually more valuable than those on their starting squares), coordination between pieces (e.g. a bishop pair usually coordinates better than a bishop plus a knight), and the type of position (knights are generally better in closed positions with many pawns, while bishops are more powerful in open positions).
Another important factor in the evaluation of chess positions is the pawn structure or pawn skeleton. Since pawns are the most immobile and least valuable of the chess pieces, the pawn structure is relatively static and largely determines the strategic nature of the position. Weaknesses in the pawn structure, such as isolated, doubled, or backward pawns and holes, once created, are usually permanent. Care must therefore be taken to avoid them unless they are compensated by another valuable asset, such as the possibility to develop an attack.
Chess strategy is the aspect of chess playing concerned with evaluation of chess positions and setting of goals and long-term plans for future play. While evaluating a position strategically, a player must take into account such factors as the relative value of the pieces on the board, pawn structure, king safety, position of pieces, and control of key squares and groups of squares (e.g. diagonals, open files, and individual squares). Chess strategy is distinguished from chess tactics, which is the aspect of play concerned with the move-by-move setting up of threats and defenses. Some authors distinguish static strategic imbalances (e.g. having more valuable pieces or better pawn structure), which tend to persist for many moves, from dynamic imbalances (such as one player having an advantage in piece development), which are temporary. This distinction affects the immediacy with which a sought-after plan should take effect. Until players reach the skill level of "master", chess tactics tend to ultimately decide the outcomes of games more often than strategy does. Many chess coaches thus emphasize the study of tactics as the most efficient way to improve one's results in serious chess play.
The most basic way to evaluate one's position is to count the total value of pieces on both sides. The point values used for this purpose are based on experience. Usually pawns are considered to be worth one point, knights and bishops three points each, rooks five points, and queens nine points. The fighting value of the king in the endgame is approximately four points. These basic values are modified by other factors such as the position of the pieces (e.g. advanced pawns are usually more valuable than those on their starting squares), coordination between pieces (e.g. a bishop pair usually coordinates better than a bishop plus a knight), and the type of position (knights are generally better in closed positions with many pawns, while bishops are more powerful in open positions).
Another important factor in the evaluation of chess positions is the pawn structure or pawn skeleton. Since pawns are the most immobile and least valuable of the chess pieces, the pawn structure is relatively static and largely determines the strategic nature of the position. Weaknesses in the pawn structure, such as isolated, doubled, or backward pawns and holes, once created, are usually permanent. Care must therefore be taken to avoid them unless they are compensated by another valuable asset, such as the possibility to develop an attack.
Basic concepts of board evaluation
A material
advantage applies both strategically and tactically. Generally more
pieces or an aggregate of more powerful pieces means greater chances of
winning. A fundamental strategic and tactical rule is to capture
opponent pieces while preserving one's own.
Bishops and knights are called minor pieces. A knight is about as valuable as a bishop, but less valuable than a rook. Rooks and the queen are called major pieces.
Bishops are usually considered slightly better than knights in open
positions, such as toward the end of the game when many of the pieces
have been captured, whereas knights have an advantage in closed
positions. Having two bishops (the bishop pair) is a particularly powerful weapon, especially if the opposing player lacks one or both of their bishops.
Three pawns are likely to be more useful than a knight in the endgame, but in the middlegame,
a knight is often more powerful. Two minor pieces are stronger than a
single rook, and two rooks are slightly stronger than a queen. The
bishop on squares of the same color as the player is slightly more
valuable in the opening as it can attack the vulnerable f7/f2-square. A
rook is more valuable when doubled with another rook or queen; consequently, doubled rooks are worth more than two unconnected rooks.
One commonly used simple scoring system is:
Piece Value Pawn 1 Knight 3 Bishop 3 Rook 5 Queen 9
The scoring system Stockfish uses is:
Piece Value Pawn 1.98 Knight 8.17 Bishop 8.36 Rook 12.70 Queen 25.21
Under a system like this, giving up a knight or bishop to win a rook ("winning the exchange")
is advantageous and is worth about two pawns. This ignores
complications such as the current position and freedom of the pieces
involved, but it is a good starting point. In an open position, bishops
are more valuable than knights (a bishop pair can easily be worth seven
points or more in some situations); conversely, in a closed position,
bishops are less valuable than knights. However, a knight in the center
of the board that cannot be taken is known as a knight outpost and threatens several fork
instances. In such a case, a knight is worth far more than a bishop.
Also, many pieces have a partner. By doubling up two knights, two rooks,
rook and queen or bishop and queen the pieces can get stronger than the
sum of the individual pieces alone. When pieces lose their partner,
their values slightly decrease. The king
is priceless since its capture results in the defeat of that player and
brings about the end of that game. However, especially in the endgame,
the king can also be a fighting piece, and is sometimes given a fighting
value of three and a half points.
Space
Other things being equal, the side that controls more space on the board has an advantage.
More space means more options, which can be exploited both tactically
and strategically. A player who has all pieces developed and no tactical
tricks or promising long-term plan should try to find a move that
enlarges their influence, particularly in the center. However, in some
openings, one player accepts less space for a time, to set up a
counterattack in the middlegame. This is one of the concepts behind hypermodern play.
The easiest way to gain space is to push the pawn skeleton
forward. However, one must be careful not to over stretch. If the
opponent succeeds in getting a protected piece behind enemy lines, this
piece can become such a serious problem that a piece with a higher value
might have to be exchanged for it.
| a | b | c | d | e | f | g | h | ||
| 8 |              | 8 | |||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
White has an advantage in space.
Larry Evans
gives a method of evaluating space. The method (for each side) is to
count the number of squares attacked or occupied on the opponent's side
of the board. In this diagram from the Nimzo-Indian Defense,
Black attacks four squares on White's side of the board (d4, e4, f4,
and g4). White attacks seven squares on Black's side of the board (b5,
c6, e6, f5, g5, and h6 – counting b5 twice) and occupies one square
(d5). White has a space advantage of eight to four and Black is cramped.
Control of the center
| a | b | c | d | e | f | g | h | ||
| 8 |               | 8 | |||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
Center squares are marked by "X".
The strategy consists of placing pieces so that they attack the
central four squares of the board. However, a piece being placed on a
central square does not necessarily mean it controls the center, e.g., a
knight on a central square does not attack any central squares.
Conversely, a piece does not have to be on a central square to control
the center. For example, the bishop can control the center from afar.
Control of the center is generally considered important because
tactical battles often take place around the central squares, from where
pieces can access most of the board. Center control allows more
movement and more possibility for attack and defense.
Chess openings try to control the center while developing pieces. Hypermodern openings are those that control the center with pieces from afar (usually the side, such as with a fianchetto); the older Classical (or Modern) openings control it with pawns.
Initiative
The initiative belongs to the player who can make threats that cannot
be ignored, such as checking the opponent's king. They thus put their
opponent in the position of having to use their turns responding to
threats rather than making their own, hindering the development of their
pieces. The player with the initiative is generally attacking and the other player is generally defending.
Defending pieces
It
is important to defend one's pieces even if they are not directly
threatened. This helps stop possible future campaigns from the opponent.
If a defender must be added at a later time, this may cost a tempo
or even be impossible due to a fork or discovered attack. The approach
of always defending one's pieces has an antecedent in the theory of Aron Nimzowitsch
who referred to it as "overprotection." Similarly, if one spots
undefended enemy pieces, one should immediately take advantage of those
pieces' weakness.
Even a defended piece can be vulnerable. If the defending piece
is also defending something else, it is called an overworked piece, and
may not be able to fulfill its task. When there is more than one
attacking piece, the number of defenders must also be increased, and
their values taken into account. In addition to defending pieces, it is
also often necessary to defend key squares, open files, and the back rank. These situations can easily occur if the pawn structure is weak.
Exchanging pieces
To exchange pieces means to capture a hostile piece and then allow a
piece of the same value to be captured. As a rule of thumb, exchanging
pieces eases the task of the defender who typically has less room to
operate in.
Exchanging pieces is usually desirable to a player with an
existing advantage in material, since it brings the endgame closer and
thereby leaves the opponent with less ability to recover ground. In the
endgame even a single pawn advantage may be decisive. Exchanging also
benefits the player who is being attacked, the player who controls less
space, and the player with the better pawn structure.
When playing against stronger players, many beginners attempt to
constantly exchange pieces "to simplify matters". However, stronger
players are often relatively stronger in the endgame, whereas errors are
more common during the more complicated middlegame.
Note that "the exchange" may also specifically mean a rook exchanged for a bishop or knight.
Specific pieces
Pawns
After 12...Re8 in Tarrasch–Euwe, 1922 ...
|
... and its pawn skeleton ("The Rauzer formation")
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In the endgame, passed pawns, unhindered by enemy pawns from promotion, are strong, especially if advanced or protected by another pawn. A passed pawn on the sixth rank is roughly as strong as a knight or bishop and often decides the game.
Knights
Since knights can easily be chased away by pawn moves, it is often advantageous for knights to be placed in holes in the enemy position as outposts—squares
where they cannot be attacked by pawns. Such a knight on the fifth rank
is a strong asset. The ideal position for a knight is the opponent's
third rank, when it is supported by one or two pawns.
A knight at the edge or corner of the board controls fewer squares than
one on the board's interior, thus the saying: "A Knight on the rim is
dim!"
A king and one knight is not sufficient material to checkmate an opposing lone king. A king and two knights can checkmate a lone king but
it cannot be forced.
Bishops
A bishop always stays on squares of the color it started on, so once
one of them is gone, the squares of that color become more difficult to
control. When this happens, pawns moved to squares of the other color do
not block the bishop, and enemy pawns directly facing them are stuck on
the vulnerable color.
A fianchettoed
bishop, e.g. at g2 after pawn g2–g3, can provide a strong defense for
the castled king on g1 and often exert pressure on the long diagonal
h1–a8. After a fianchetto, giving up the bishop can weaken the holes in
the pawn chain; doing so in front of the castled king may thus affect
its safety.
In general, a bishop is of roughly equal value to a knight. In
certain circumstances, one can be more powerful than the other. If the
game is "closed" with lots of interlocked pawn formations, the knight
tends to be stronger, because it can hop over the pawns while they block
the bishop. A bishop is also weak if it is restricted by its own pawns,
especially if they are blocked and on the bishop's color. Once a bishop
is lost, the remaining bishop is considered weaker since the opponent
can now plan their moves to play a white or black color game.
In an open position
with action on both sides of the board, the bishop tends to be stronger
because of its long range. This is especially true in the endgame; if
passed pawns race on opposite sides of the board, the player with a
bishop usually has better winning chances than a player with a knight.
A king and a bishop is not sufficient material to checkmate an
opposing lone king, but two bishops and a king checkmate an opposing
lone king easily.
Rooks
Rooks have more scope of movement on half-open files
(ones with no pawns of one's own color). Rooks on the seventh rank can
be very powerful as they attack pawns that can only be defended by other
pieces, and they can restrict the enemy king to its back rank. A pair
of rooks on the player's seventh rank is often a sign of a winning
position.
In middlegames and endgames with a passed pawn, Tarrasch's rule states that rooks, both friend and foe of the pawn, are usually strongest behind the pawn rather than in front of it.
A king and a rook is sufficient material to checkmate an opposing
lone king, although it's a little harder than checkmating with king and
queen; thus the rook's distinction as a major piece above the knight
and bishop.
Queen
Queens are the most powerful pieces. They have great mobility and can
make many threats at once. They can act as a rook and as a bishop at
the same time. For these reasons, checkmate
attacks involving a queen are easier to achieve than those without one.
Although powerful, the queen is also easily harassed. Thus, it is
generally wise to wait to develop
the queen until after the knights and bishops have been developed to
prevent the queen from being attacked by minor pieces and losing tempo. When a pawn is promoted, most of the time it is promoted to a queen.
King
During the middle game, the king is often best protected in a corner
behind its pawns. Such a position for either of the players is often
achieved by castling by that player. If the rooks and queen leave the first rank (commonly called that player's back rank), however, an enemy rook or queen can checkmate the king by invading the first rank, commonly called a back-rank checkmate. Moving one of the pawns in front of the king (making a luft)
can allow it an escape square, but may weaken the king's overall safety
otherwise. One must therefore wisely balance between these trade-offs.
Castling is often thought to help protect the king and often
"connects" the player's two rooks together so the two rooks may protect
each other. This can reduce a threat of a back-rank skewer in which the king can be skewered with capture of a rook behind it.
The king can become a strong piece in the endgame. With reduced
material, a quick checkmate becomes less of a concern, and moving the
king towards the center of the board gives it more opportunities to make
threats and actively influence play.
Considerations for a successful long term deployment
Chess
strategy consists of setting and achieving long-term goals during the
game—for example, where to place different pieces—while tactics
concentrate on immediate maneuver. These two parts of chess thinking
cannot be completely separated, because strategic goals are mostly
achieved by the means of tactics, while the tactical opportunities are
based on the previous strategy of play.
Because of different strategic and tactical patterns, a game of chess is usually divided into three distinct phases: Opening, usually the first 10 to 25 moves, when players develop their armies and set up the stage for the coming battle; middlegame, the developed phase of the game; and endgame, when most of the pieces are gone and kings start to take an active part in the struggle.
Opening
A chess opening is the group of initial moves of a game (the "opening
moves"). Recognized sequences of opening moves are referred to as openings and have been given names such as the Ruy Lopez or Sicilian Defence. They are catalogued in reference works such as the Encyclopaedia of Chess Openings.
It is recommended for anyone but the chessmasters that when left with a
choice to either invent a new variation or follow a standard opening,
choose the latter.
There are dozens of different openings, varying widely in character from quiet positional play (e.g. the Réti Opening) to very aggressive (e.g. the Latvian Gambit). In some opening lines, the exact sequence considered best for both sides has been worked out to 30–35 moves or more. Professional players spend years studying openings, and continue doing so throughout their careers, as opening theory continues to evolve.
The fundamental strategic aims of most openings are similar:
- Development: To place (develop) the pieces (particularly bishops and knights) on useful squares where they influence the game.
- Control of the center: Control of the central squares allows pieces to be moved to any part of the board relatively easily, and can also have a cramping effect on the opponent.
- King safety: Correct timing of castling can enhance this.
- Pawn structure: Players strive to avoid the creation of pawn weaknesses such as isolated, doubled or backward pawns, and pawn islands.
During the opening, some pieces have a recognized optimum square they
try to reach. Hence, an optimum deployment could be to push the king
and queen pawn two steps followed by moving the knights so they protect
the center pawns and give additional control of the center. One can then
deploy the bishops, protected by the knights, to pin
the opponent's knights and pawns. The optimum opening is ended with a
castling, moving the king to safety and deploying for a strong back rank
and a rook along the center file.
Apart from these fundamentals, other strategic plans or tactical sequences may be employed in the opening.
Most players and theoreticians consider that White, by virtue of the first move, begins the game with a small advantage. Black usually strives to neutralize White's advantage and achieve equality, or to develop dynamic counterplay in an unbalanced position.
Middlegame
The middlegame is the part of the game when most pieces have been
developed. Because the opening theory has ended, players have to assess
the position, to form plans based on the features of the positions, and
at the same time to take into account the tactical possibilities in the
position.
Typical plans or strategic themes—for example the minority attack, that is the attack of queenside pawns against an opponent who has more pawns on the queenside—are often appropriate just for some pawn structures,
resulting from a specific group of openings. The study of openings
should therefore be connected with the preparation of plans typical for
resulting middlegames.
Middlegame is also the phase when most combinations
occur. Middlegame combinations are often connected with the attack
against the opponent's king; some typical patterns have their own names,
for example the Boden's Mate or the Lasker—Bauer combination.
Another important strategical question in the middlegame is
whether and how to reduce material and transform into an endgame (i.e. simplify).
For example, minor material advantages can generally be transformed
into victory only in an endgame, and therefore the stronger side must
choose an appropriate way to achieve an ending. Not every reduction of
material is good for this purpose; for example, if one side keeps a
light-squared bishop and the opponent has a dark-squared one, the
transformation into a bishops and pawns ending is usually advantageous for the weaker side only, because an endgame with bishops on opposite colors is likely to be a draw, even with an advantage of one or two pawns.
Endgame
| a | b | c | d | e | f | g | h | ||
| 8 | | 8 | |||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
An example of zugzwang: The side to move has a disadvantage.
The endgame (or end game or ending) is the stage of the
game when there are few pieces left on the board. There are three main
strategic differences between earlier stages of the game and endgame:
- During the endgame, pawns become more important; endgames often revolve around attempting to promote a pawn by advancing it to the eighth rank.
- The king, which must be protected in the middlegame owing to the threat of checkmate, becomes a strong piece in the endgame and it is often brought to the center of the board where it can protect its own pawns, attack the pawns of opposite color, and hinder movement of the opponent's king.
- Zugzwang, a disadvantage because the player has to make a move, is often a factor in endgames and rarely in other stages of the game. For example, in the adjacent diagram, Black on move must go 1...Kb7 and allow white to queen after 2.Kd7, while White on move must allow a draw either after 1.Kc6 stalemate or losing the last pawn by going anywhere else.
Endgames can be classified according to the type of pieces that remain on board. Basic checkmates
are positions where one side has only a king and the other side has one
or two pieces and can checkmate the opposing king, with the pieces
working together with their king. For example, king and pawn endgames
involve only kings and pawns on one or both sides and the task of the
stronger side is to promote one of the pawns. Other more complicated
endings are classified according to the pieces on board other than
kings, e.g. "rook and pawn versus rook endgame".
Quotes
- "Strategy requires thought; tactics require observation." – Max Euwe
- "To play according to textbooks is fine, up to a certain level. Perhaps up to master level, but not to grandmasters." – Vladimir Kramnik[11]
