PERPETUAL CHECK

In the game of chess, 'perpetual check' is a special case of draw by threefold repetition, in which one player forces the repetition by an unending series of checks. Such a situation typically arises when the player forcing the repetition 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 . Howard Staunton gave it as one of six ways to draw a game in ''The Chess-Player's Handbook'' . 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 .
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

Examples

See also

References

External links

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.
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.

In the third diagram, from the classic game Hamppe-Meitner, Vienna 1872,[2] Black, having already sacrificed most of his pieces, forced a draw with '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'.

See also

★ Rules of chess

★ Desperado piece

★ Stalemate

References

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★

★ (1985 Batsford reprint, ISBN 1-85958-005-X)

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★ Project Gutenberg has the text of a different reprint from 1870 and 1910 at The Blue Book of Chess by Howard Staunton and Various

External links

★ Diagram demonstrating a perpetual check