Perpetual check

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This article uses algebraic notation to describe chess moves.

In the game of chess, perpetual check is a situation in which one player can force a draw by an unending series of checks. Such a situation typically arises when the player who is checking cannot deliver checkmate, while any other move gives the opponent a chance to win.

A draw by perpetual check used to be in the rules of chess (Reinfeld 1954:175). Howard Staunton gave it as one of six ways to draw a game in The Chess-Player's Handbook (Staunton 1847:21–22). It has since been removed since perpetual check will eventually allow a draw claim by either threefold repetition or the fifty move rule. If a player demonstrates intent to perform perpetual check, the players usually agree to a draw (Hooper & Whyld 1992).

Perpetual check can also occur in other chess variants, although the rules relating to it may be different. For example, giving perpetual check is not allowed (an automatic loss for the giver) in both shogi and xiangqi.

Contents 1 Examples 1.1 Unzicker-Averbakh 1.2 Hamppe-Meitner 1.3 Leko-Kramnik 1.4 Fischer-Tal 2 See also 3 References 4 External links

[edit] Examples

In the first diagram, White is in danger of losing. But if it is White's move, he draws:

1. Qc8+ Kh7

2. Qf5+ Kg8 (or 2... Kh8)

3. Qc8+ Kh7

4. Qf5+ g6

5. Qxf7+ Kh8

6. Qf8+ Kh7

7. Qf7+ etc.

[edit] Unzicker-Averbakh

In the second diagram, from Unzicker-Averbakh, Stockholm Interzonal 1952,[1] Black (on move) would soon be forced to give up one of his rooks for White's c-pawn (to prevent it from promoting or to capture the promoted queen after promotion). He can, however, exploit the weakness of White's kingside pawn structure with

• 1... Rxc7!
• 2. Qxc7 Ng4! (threatening 3...Qh2#)
• 3. hxg4 Qf2+

salvaging a draw by threefold repetition with checks on h4 and f2.

[edit] Hamppe-Meitner

In the classic game Hamppe-Meitner, Vienna 1872,[2] following a series of sacrifices Black forces the game to the position in the diagram, a perpetual check:

• 16...Bb7+
• 17.Kb5 (17.Kxb7?? Kd7 18.Qg4+ Kd6 followed by ...Rhb8#)
• 17...Ba6+
• 18.Kc6 (18.Ka4?? Bc4 and 19...b5#)
• 18...Bb7+ ½-½.

[edit] Leko-Kramnik

In the game between Peter Leko and Vladimir Kramnik at the 2008 Corus tournament, Black was able to obtain a draw because of perpetual check:

• 24... Qb4+
• 25. Ka2 Qa4+
• 26. Kb2 Qb4+
• 27. Kc1 Qa3+
• 28. Kb1 ½–½

[edit] Fischer-Tal

A perpetual check saved a draw for Mikhail Tal against Bobby Fischer in this 1960 game, played in the 14th Chess Olympiad, while Tal was the World Champion. Now Black played 21... Qg4+ and the game was drawn (Evans 1970:53). (After 22. Kh1 then 22... Qf3+ 23. Kg1 Qg4+ forces perpetual check.)

[edit] See also

• Rules of chess
• Desperado
• Stalemate

[edit] References

• Evans, Larry (1970), Modern Chess Brilliancies, Fireside, ISBN 0-671-22420-4 
• Hooper, David & Whyld, Kenneth (1992), The Oxford Companion to Chess (second ed.), Oxford University Press, ISBN 0-19-866164-9 
• Reinfeld, Fred (1954), How To Be A Winner At Chess, Fawcett, ISBN 0-449-91206-X 
• Staunton, Howard (1847), The Chess-Player's Handbook, London: H. G. Bonh, pp. 21–22  (1985 Batsford reprint, ISBN 1-85958-005-X)
  • Project Gutenberg has the text of a different reprint from 1870 and 1910 at The Blue Book of Chess by Howard Staunton and Various

[edit] External links

• Diagram demonstrating a perpetual check