Cross-check

From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about a chess move. For the penalty in ice hockey, see Cross checking.

In chess, a cross-check is a tactic in which a check is played in response to a check, especially when the original check is blocked by a piece that itself either delivers check or reveals a discovered check from another piece. Sometimes the term is extended to cover cases in which the king moves out of check and reveals a discovered check from another piece (this is also known as a royal check); it does not generally apply to cases where the original checking piece is captured.

The cross-check is an essential tactic in winning some endgames such as those with two queens versus one, or a queen and pawn versus a queen. In these cases, the defense usually tries for a perpetual check and sometimes the stronger side can stop it only by a cross-check.


Examples[edit]

A cross-check occurs from time to time in games. It is an essential tactic in winning endgames such as two queens versus one queen, or queen and pawn versus queen, where it is used to stop a series of checks from the opponent and force the exchange of queens. It is also used in some chess problems.

Botvinnik vs. Minev game[edit]

Botvinnik vs. Minev, 1954
a b c d e f g h
8
Chessboard480.svg
c7 black circle
g7 white pawn
c6 white circle
c5 white king
d5 white queen
a4 black king
c4 white circle
d4 white circle
c2 black circle
f2 black circle
h2 black queen
g1 black circle
8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
a b c d e f g h
Black, to move, resigned. Black dots are where the black queen can check; white dots are where the white queen can cross-check in reply.

Cross-checks are rare in actual play, though they do occur, and in some endgames, particularly queen endgames, they are very important. The position shown to the right is the final position in the famous queen endgame from the game [1] between Mikhail Botvinnik and Nikolay Minev, Amsterdam Olympiad, 1954. In the position shown, after 91. Kc5!!, Black resigned because the promising looking checks 91...Qc7+, 91...Qg1+, 91...Qf2+ and 91...Qc2+ are answered by the cross-checks 92.Qc6+, 92.Qd4+, 92.Qd4+ and 92.Qc4+ respectively, forcing an exchange of queens in all cases, which will result in the promotion of the pawn and winning the game by a basic checkmate. This is an important theme in queen endgames: the weaker side often gives a series of checks, and it is frequently important for them to avoid simplifying cross-checks such as these in reply (Burgess 2000:102–3, 458–59), (Golombek 1977). If the black queen attacks the pawn instead of checking it does no good since the promotion square of the pawn is protected by its queen.

Two queens versus one[edit]

Botvinnik vs. Ravinsky, 1944
a b c d e f g h
8
Chessboard480.svg
c8 black queen
g7 white pawn
g6 white king
a4 black king
f4 white queen
8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
a b c d e f g h
Black resigned after 126.Qf4+.
Possible continuation
a b c d e f g h
8
Chessboard480.svg
b8 black queen
e8 white circle
f8 white king
e7 white queen
f7 white queen
a4 black king
8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
a b c d e f g h
Cross-check with 135.Qee8+ wins.

In the position on the left from Botvinnik–Ravinsky,[2] Black resigned. With best play according to the endgame tablebase, 126...Kb3 127.Qf7+ Ka4 128.g8=Q Qg4+ 129.Kh6 Qh4+ 130.Kg7 Qg3+ 131.Kf8 Qd6+ 132.Qe7 Qh6+ 133.Qgg7 Qf4+ 134.Qgf7 Qb8+ and the position on the right is reached. Then the cross-check 135.Qee8+ (or Qfe8+) forks the king and queen, forces an exchange, and wins the game.

Anderson problem, 1919[edit]

G.F. Anderson, 1919
a b c d e f g h
8
Chessboard480.svg
c7 white king
e7 white queen
f7 black pawn
h7 black bishop
c6 black pawn
b5 black king
a3 white rook
b3 white bishop
c3 black pawn
g3 black rook
b1 white rook
8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
a b c d e f g h

Cross-checks are relatively infrequent in actual play, but are popular in chess problems since they make for a relatively unobvious solution. In the problem shown to the right, White is to move and mate in two moves against any defence. It is by G.F. Anderson and was first published in Il Secolo in 1919. The key 1.Kd6, threatening 2.Qb7#, gives the black king two flight squares, and two of the variations exploit these: 1...Kb6 2.Bc2# and 1...Kb4 2.Kxc6#. The other two defences exploit the fact that the key exposes the white king to checks, and are answered by cross-checks: 1...Rg6+ 2.Be6# and 1...Rd3+ 2.Bd5#.

Anderson problem, 1961[edit]

G. F. Anderson, The Observer, 1961
a b c d e f g h
8
Chessboard480.svg
d8 white queen
f8 black bishop
h8 black knight
a7 black rook
e7 black pawn
h7 white king
a6 black pawn
c6 white pawn
d6 white pawn
e6 white pawn
f6 white pawn
h6 black pawn
a5 white rook
c5 white knight
e5 black king
f5 black knight
h5 black rook
c4 white bishop
f4 white rook
g4 white pawn
e3 black pawn
g3 white bishop
h3 white knight
f2 black pawn
h2 black queen
b1 black bishop
8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
a b c d e f g h

The problem to the right, also by G. F. Anderson (first published in The Observer in 1961) and also a mate in two, features no less than five cross-checks. The key is 1.Qb6 (threat: 2.Ne4#), with the following variations:

1...exf6+ 2.Nb7#
1...exd6+ 2.Nd7#
1...Nd4+ 2.Rf5#
1...Nxd6+ 2.Nd3#
1...Nf-other+ 2.Ne4#
1...Kxf6 2.Qb2#
1...Kxd6 2.Rd4#

See also[edit]

Notes[edit]

References[edit]

Further reading[edit]

  • John Rice, Chess Wizardry: The New ABC of Chess Problems (London, Batsford, 1996)

External links[edit]