Fork (chess)

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8
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a8 black rook
d7 black king
b6 white knight
g4 black pawn
f3 white rook
h3 white rook
c1 white king
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The white knight forks Black's king and rook. Black's pawn forks the white rooks.

In chess, a fork is a tactic in which a piece attacks two or more pieces simultaneously. The attacker usually aims to capture one of the forked pieces, or threaten checkmate. The defender often finds it difficult to counter two or more threats in a single move.

A fork is most effective when it is forcing, such as when the king is put in check.

Apart from pawns on an outside file, any piece can fork, but knight forks are the most striking, since the knight is a minor piece and can be traded, and because, except in the case of other knights, a knight cannot be captured by the piece it is threatening.[1]

Since the queen is usually more valuable than the pieces it attacks, a queen fork gains material only when the pieces attacked are undefended or if one of them is the king and the other is undefended.

Terminology[edit]

A fork is also known as a double attack. The type of fork is named after the type of forking piece. For example, a knight fork. The attacked pieces are forked.[2] If the King is one of the attacked pieces, the term absolute fork is sometimes used. A fork not involving the enemy king is in contrast a relative fork.[3]

A fork of the king and queen, the highest material-gaining fork possible, is sometimes called a royal fork. A fork of the enemy king, queen, and one (or both) rooks is sometimes called a grand fork.[4] A knight fork of the enemy king, queen, and possibly other pieces is sometimes called a family fork or family check.

Game examples[edit]

Tissir vs. Dreev, 2004
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8
Chessboard480.svg
a8 black rook
g8 black king
b7 black pawn
d7 black queen
f7 black pawn
g7 black bishop
h7 black pawn
g6 black pawn
c5 white pawn
d5 black pawn
a4 black pawn
e4 black knight
f4 white queen
a3 white pawn
f3 white pawn
a2 white bishop
d2 white bishop
g2 white pawn
h2 white pawn
c1 white rook
h1 white king
8
77
66
55
44
33
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Position after 33.Qe5–f4


This example is from the first round of the FIDE World Chess Championship 2004 between Mohamed Tissir and Alexey Dreev.[5] After

 33... Nf2+ 34. Kg1 Nd3

White resigned. In the final position the black knight forks White's queen and rook; after the queen moves away, Black will win the exchange.

Soppe vs. Braga, 1998
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8
Chessboard480.svg
g8 black king
f7 black pawn
g7 black bishop
e6 black pawn
h6 black pawn
b5 black pawn
d5 black knight
e5 white knight
e4 black queen
g4 white pawn
b3 white pawn
h3 white pawn
f2 white pawn
c1 white bishop
d1 white queen
f1 white king
8
77
66
55
44
33
22
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Position after 40.Nxe5


This example is from the ninth round of the Clarin GP Final between Guillermo Soppe and Fernando Braga.[6] After

 40... Qh1+

White resigned. The only move is 41.Ke2 which enables a royal fork with 41...Nc3+, winning the queen.

abcdefgh
8
Chessboard480.svg
a8 black rook
c8 black bishop
d8 black queen
e8 black king
f8 black bishop
h8 black rook
a7 black pawn
b7 black pawn
c7 black pawn
d7 black pawn
f7 black pawn
g7 black pawn
h7 black pawn
c6 black knight
f6 black knight
e5 black pawn
c4 white bishop
e4 white pawn
c3 white knight
f3 white knight
a2 white pawn
b2 white pawn
c2 white pawn
d2 white pawn
f2 white pawn
g2 white pawn
h2 white pawn
a1 white rook
c1 white bishop
d1 white queen
e1 white king
h1 white rook
8
77
66
55
44
33
22
11
abcdefgh
Position after 4.Nc3. Black can play 4...Nxe4 since he has a fork trick.
abcdefgh
8
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a8 black rook
c8 black bishop
d8 black queen
e8 black king
f8 black bishop
h8 black rook
a7 black pawn
b7 black pawn
c7 black pawn
f7 black pawn
g7 black pawn
h7 black pawn
c6 black knight
d5 black pawn
e5 black pawn
c4 white bishop
e4 white knight
f3 white knight
a2 white pawn
b2 white pawn
c2 white pawn
d2 white pawn
f2 white pawn
g2 white pawn
h2 white pawn
a1 white rook
c1 white bishop
d1 white queen
e1 white king
h1 white rook
8
77
66
55
44
33
22
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After 4...Nxe4 5.Nxe4 d5, White is forked and Black will regain a piece.

In the Two Knights Defense (1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6) after 4.Nc3, Black can eliminate White's e4-pawn immediately with

4... Nxe4!

due to the fork trick

5. Nxe4 d5

regaining either the bishop or the knight.

References[edit]

  1. ^ "Fork in Chess - Chess Terms". Chess.com. Retrieved 2021-04-09.
  2. ^ "The Fork • lichess.org". lichess.org. Retrieved 2021-04-09.
  3. ^ https://www.chess-game-strategies.com/chess-fork.html
  4. ^ An example of a king, queen and double rook fork can be found in the 9th game in a September 2020 match between IM Eric Rosen and the Botez sisters that ended 9½-½. See Video on YouTube (Rosen's perspective) and Video on YouTube (the Botez' perspective).
  5. ^ "Tissir vs. Dreev, Tripoli 2004". Chessgames.com.
  6. ^ "Guillermo Soppe vs Fernando Braga, (1998)". Chessgames.com.

Further reading[edit]