Perpetual check

<h2 id="examples">Examples</h2>

<p>In this diagram, Black is ahead a <a href="/facts/Rook_(chess)/Douvk8Nu">rook</a>, a <a href="/facts/Bishop_(chess)/d1jHm7Ec">bishop</a>, and a <a href="/facts/Pawn_(chess)/Xk3E1UIN">pawn</a>, which would normally be a decisive <a href="/facts/Glossary_of_chess/bh0g4wCP">material</a> advantage. But White, to move, can draw by perpetual check:
</p>
1. Qe8+ Kh7
2. Qh5+ Kg8
3. Qe8+ etc.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
<p>The same position will soon repeat for the third time and White can claim a draw by threefold repetition; or the players will agree to a draw. 
</p>

<h3>Unzicker vs. Averbakh</h3>

<p>In the diagram, from <a href="/facts/Wolfgang_Unzicker/b6d81JFu">Wolfgang Unzicker</a>–<a href="/facts/Yuri_Averbakh/n16GsDKI">Yuri Averbakh</a>, Stockholm <a href="/facts/Interzonal/9Nt1F9wG">Interzonal</a> 1952,<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> Black (on move) would soon be forced to give up one of his <a href="/facts/Rook_(chess)/Douvk8Nu">rooks</a> for White's c-<a href="/facts/Pawn_(chess)/Xk3E1UIN">pawn</a> (to prevent it from <a href="/facts/Promotion_(chess)/V1rtTYu2">promoting</a> or to capture the promoted <a href="/facts/Queen_(chess)/sHWc1RMX">queen</a> after promotion). He can, however, exploit the weakness of White's <a href="/facts/Glossary_of_chess/bh0g4wCP">kingside</a> <a href="/facts/Pawn_structure/2g7xqcfh">pawn structure</a> with 
</p>
27... Rxc7<a href="/facts/Chess_annotation_symbols/3LG0bJ87">!</a>
28. Qxc7 Ng4!
<p>Threatening 29...Qh2<a href="/facts/Algebraic_notation_(chess)/gU96RuM3">#</a>. If 29.hxg4 then 29...Qf2+, salvaging a draw by threefold repetition with checks by moving the queen alternatively to f2 and h4.
</p>

<h3>Hamppe vs. Meitner</h3>
<p class="note">Main article: <a href="/facts/Immortal_Draw/Uwg7U0Vq">Immortal Draw</a></p>

<p>In a classic game <a href="/facts/Carl_Hamppe/oFqE0xg5">Carl Hamppe</a>–<a href="/facts/Philipp_Meitner/zEuNDzgf">Philipp Meitner</a>, Vienna 1872,<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> following a series of <a href="/facts/Sacrifice_(chess)/zBtU8hoK">sacrifices</a> Black forced the game to the position in the diagram, where he drew by a perpetual check: 
</p>
16... Bb7+!
17. Kb5
<p>If 17.Kxb7<a href="/facts/Chess_annotation_symbols#??/3LG0bJ87">??</a> Kd7 18.Qg4+ Kd6 followed by ...Rhb8#.
</p>
17... Ba6+
18. Kc6
<p>If 18.Ka4<a href="/facts/Chess_annotation_symbols#?/3LG0bJ87">?</a>, 18...Bc4 and 19...b5#.
</p>
18... Bb7+ <a href="/facts/Algebraic_notation_(chess)/gU96RuM3">½–½</a>

<h3>Leko vs. Kramnik</h3>

<p>In the game <a href="/facts/Peter_Leko/R33IzceP">Peter Leko</a>–<a href="/facts/Vladimir_Kramnik/4nqctqAw">Vladimir Kramnik</a>, <a href="/facts/Corus_chess_tournament/YFYr6U0b">Corus</a> 2008, Black was able to obtain a draw because of perpetual check:<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p>
24... Qb4+
25. Ka2 Qa4+
26. Kb2 Qb4+
27. Kc1 Qa3+
28. Kb1 ½–½
<p>If 28.Kd2? Rd8+ 29.Ke2 Qe7+.
</p>

<h3>Fischer vs. Tal</h3>
<table><tbody><tr><td></td><td></td></tr></tbody></table>
<p>A perpetual check saved a draw for <a href="/facts/Mikhail_Tal/xamK2V7L">Mikhail Tal</a> in the game <a href="/facts/Bobby_Fischer/J2gfeEyD">Bobby Fischer</a>–Tal, Leipzig 1960,<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> played in the <a href="/facts/14th_Chess_Olympiad/X0VNHSCW">14th Chess Olympiad</a>, while Tal was <a href="/facts/World_Chess_Championship/XPdyx85g">World Champion</a>.  In this position Black played 
</p>
 21... Qg4+
<p>and the game was drawn.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>  (After 22.Kh1, then 22...Qf3+ 23.Kg1 Qg4+ forces perpetual check.)
</p>

<h2 id="mutual-perpetual-check">Mutual perpetual check</h2>

<p>A mutual perpetual check is not possible using only the orthodox chess pieces, but it is possible using some <a href="/facts/Fairy_chess_piece/eCFMrkJa">fairy chess pieces</a>. In the diagram, the pieces represented as inverted knights are <a href="/facts/Nightrider_(chess)/a8uT0PId">nightriders</a>: they move any number of knight moves in a given direction until they are blocked by any piece along the path (that is, a nightrider is to a knight as a queen is to a king, ignoring the rules on check). There could follow:
</p>
1. Ke3+ Kd5+
2. Kd3+ Ke5+
3. Ke3+ Kd5+
<p>and so on. This is in fact a mutual perpetual <i>discovered</i> check.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>
</p>

<p><a href="/facts/Noam_Elkies/t1Uerz9E">Noam Elkies</a> devised in 1999 a mutual discovered perpetual check position that requires only one fairy piece. The piece represented by an inverted knight here is a <a href="/facts/Camel_(chess)/moEdYXVp">camel</a>, a (1,3)-leaper. There could follow:
</p>
1. Nb5+ Cc5+
2. Nd4+ Cb2+
3. Nb5+ Cc5+
<p>and so on.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>
</p><p><a href="/facts/Xiangqi/qLYL3APs">Xiangqi</a> and <a href="/facts/Janggi/fTHaymys">janggi</a>, due to the presence of their cannon pieces, can also have mutual perpetual check.
</p>

<h2 id="perpetual-pursuit">Perpetual pursuit</h2>

<p>Related to perpetual check is the <i>perpetual pursuit</i>, which differs in that the continually attacked piece is not the king. The result is similar, in that the opposing side's attack stalls because of the need to respond to the continuous threats.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a>
</p><p>In the Birnov study illustrated, White's situation seems hopeless: they are down a piece and cannot stop Black's h-pawn, and their passed a-pawn can easily be stopped by Black's bishop. However, they can save themself by restricting the bishop's movement to set up a perpetual pursuit. They begin:
</p>
1. a6 Bxc4
<p>A direct pawn race with 1...h3? fails, as White promotes first and covers the promotion square.
</p>
2. e4+!
<p>This pawn sacrifice forces Black to limit their bishop's scope along the long diagonal.
</p>
2... Kxe4
<p>Forced, as Black has to play ...Bd5 to stop the pawn.
</p>
3. a7 Bd5
4. c4!
<p>Denying another square to the bishop, which must stay on the a8–h1 diagonal. This forces
</p>
4... Ba8
<p>And White can then begin the perpetual pursuit:
</p>
5. Kb8 Bc6
6. Kc7 Ba8
<p>Black can make no progress.
</p>
Bilek vs. Schüssler, 1978<table><tbody><tr><td><table><tbody><tr><td></td><td></td></tr></tbody></table></td></tr></tbody></table>
<p>An example of perpetual pursuit being used in a game occurred in <a href="/facts/Istv%C3%A1n_Bilek/vAvlfbnc">István Bilek</a>–<a href="/facts/Harry_Sch%C3%BCssler/xWobbqrq">Harry Schüssler</a>, Poutiainen Memorial 1978. Bilek thought he could win the enemy queen with the combination
</p>
10. Nf6+ gxf6
11. Bxf7+ Kxf7
12. Qxd8
<p>However, Schüssler replied
</p>
12... Nd5! ½–½
<p>and Bilek conceded the draw. His queen is now trapped, and with ...Bb4+ threatening to win it, he has nothing better than 13.0-0 Bg7 14.Qd6 Bf8 15.Qd8 Bg7 with another perpetual pursuit.
</p>

<h2 id="history">History</h2>

<p>The <i>Oxford Encyclopedia of Chess Games, Volume 1 (1485–1866)</i> includes all recorded games played up to 1800.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> The earliest example of perpetual check contained in it is a game played by two unknown players in 1750:
</p>
<a href="/facts/Glossary_of_chess/bh0g4wCP">N.N.</a> vs. Unknown, 1750 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. 0-0 (the rules of <a href="/facts/Castling/S20sKRjc">castling</a> not yet having been standardized in their current form, White moved his king to h1 and his rook to f1) 4... Nf6 5. Nc3 Ng4 6. d3 0-0 (Black moved his king to h8 and his rook to f8) 7. Ng5 d6 8. h3 h6 9. Nxf7+ Rxf7 10. Bxf7 Qh4 11. Qf3 Nxf2+ 12. Rxf2 Bxf2 13. Nd5 Nd4 14. Ne7 Nxf3 15. Ng6+ Kh7 ½–½ in light of 16.Nf8+ Kh8 17.Ng6+ etc.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a>
<p>The next examples of perpetual check in the book are two games, both ending in perpetual check, played in 1788 between Bowdler and <a href="/facts/Fran%C3%A7ois-Andr%C3%A9_Danican_Philidor/L4hwwIsA">Philidor</a>, with Philidor giving <a href="/facts/Chess_handicap/ATDtXUql">odds</a> of <a href="/facts/Pawn_and_move/ATDtXUql">pawn and move</a>.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a>
</p><p>A draw by perpetual check used to be in the <a href="/facts/Rules_of_chess/qjw2lFA9">rules of chess</a>.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a><a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a>  <a href="/facts/Howard_Staunton/XEjlbIfE">Howard Staunton</a> gave it as one of six ways to draw a game in <i>The Chess-Player's Handbook</i>.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a> It has since been removed because perpetual check will eventually allow a draw claim by either <a href="/facts/Threefold_repetition/W3Sup0Cp">threefold repetition</a> or the <a href="/facts/Fifty-move_rule/DWqGGMAQ">fifty-move rule</a>.  If a player demonstrates intent to perform perpetual check, the players usually <a href="/facts/Draw_by_agreement/4yJHSlVb">agree to a draw</a>.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a>
</p>

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Desperado_(chess)/h6nEvnIo">Desperado</a></li>
<li><a href="/facts/Rules_of_chess/qjw2lFA9">Rules of chess</a></li>
<li><a href="/facts/Stalemate/guNfdBrR">Stalemate</a></li></ul>

<p>Bibliography
</p>
<ul><li><a href="/facts/Graham_Burgess/E7nzh3lw">Burgess, Graham</a> (2000), <i>The Mammoth Book of Chess</i> (2nd ed.), Carroll & Graf, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-7867-0725-6</li>
<li><a href="/facts/Larry_Evans_(chess_grandmaster)/VGInyYfI">Evans, Larry</a> (1970), <i>Modern Chess Brilliancies</i>, Fireside, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-671-22420-4</li>
<li><a href="/facts/David_Vincent_Hooper/t9VTSeDs">Hooper, David</a>; <a href="/facts/Kenneth_Whyld/jwmoGpzo">Whyld, Kenneth</a> (1992), <i><a href="/facts/The_Oxford_Companion_to_Chess/X4aMlkw7">The Oxford Companion to Chess</a></i> (2nd ed.), <a href="/facts/Oxford_University_Press/CYyTzzWG">Oxford University Press</a>, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-19-866164-9</li>
<li><a href="/facts/David_Levy_(chess_player)/CzbJXDcX">Levy, David</a>; O'Connell, Kevin (1981), <i>Oxford Encyclopedia of Chess Games, Volume 1 (1485-1866)</i>, <a href="/facts/Oxford_University_Press/CYyTzzWG">Oxford University Press</a>, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-19-217571-8</li>
<li><a href="/facts/Fred_Reinfeld/wAwfQxeA">Reinfeld, Fred</a> (1954), <i>How To Be A Winner At Chess</i>, Fawcett, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-449-91206-X</li>
<li>Reinfeld, Fred (1958), <i>Chess in a Nutshell</i>, Pocket</li>
<li><a href="/facts/Howard_Staunton/XEjlbIfE">Staunton, Howard</a> (1847), <i>The Chess-Player's Handbook</i>, London: Henry G. Bohn (1985 Batsford reprint, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 1-85958-005-X)</li></ul>
<h2 id="external-links">External links</h2>
<ul><li><a href="http://www.chessvariants.com/d.chess/eternal.html">Perpetual Check</a> by <a href="/facts/Hans_Bodlaender/D7g6rsQ1">Hans Bodlaender</a>, <i><a href="/facts/The_Chess_Variant_Pages/PIwm3KcA">The Chess Variant Pages</a></i></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>(Burgess 2000:478) - Burgess, Graham (2000), The Mammoth Book of Chess (2nd ed.), Carroll & Graf, ISBN 978-0-7867-0725-6 <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>(Reinfeld 1958:42–43) - Reinfeld, Fred (1958), Chess in a Nutshell, Pocket <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>"Unzicker vs. Averbakh, Stockholm 1952". Chessgames.com. <a href="http://www.chessgames.com/perl/chessgame?gid=1153024" target="_blank">http://www.chessgames.com/perl/chessgame?gid=1153024</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>"Hamppe vs. Meitner, Vienna 1872". Chessgames.com. <a href="http://www.chessgames.com/perl/chessgame?gid=1250160" target="_blank">http://www.chessgames.com/perl/chessgame?gid=1250160</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>"Leko vs. Kramnik, Wijk aan Zee 2008". Chessgames.com. <a href="http://www.chessgames.com/perl/chessgame?gid=1482384" target="_blank">http://www.chessgames.com/perl/chessgame?gid=1482384</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>"Fischer vs. Tal, Leipzig 1960". Chessgames.com. <a href="http://www.chessgames.com/perl/chessgame?gid=1008399" target="_blank">http://www.chessgames.com/perl/chessgame?gid=1008399</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>(Evans 1970:53) - Evans, Larry (1970), Modern Chess Brilliancies, Fireside, ISBN 0-671-22420-4 <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Tim Krabbé, Open chess diary – see item 120 <a href="http://timkr.home.xs4all.nl/chess2/diary_6.htm" target="_blank">http://timkr.home.xs4all.nl/chess2/diary_6.htm</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>Tim Krabbé, Open chess diary – see item 125 <a href="http://timkr.home.xs4all.nl/chess2/diary_7.htm" target="_blank">http://timkr.home.xs4all.nl/chess2/diary_7.htm</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
<li id="fn:10"><p>Seirawan, Yasser; Silman, Jeremy (2003). Winning Chess Tactics. London: Everyman Chess. pp. 119–121. ISBN 1857443330. <a href="1857443330" target="_blank">1857443330</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li>
<li id="fn:11"><p>(Levy & O'Connell 1981:ix) - Levy, David; O'Connell, Kevin (1981), Oxford Encyclopedia of Chess Games, Volume 1 (1485-1866), Oxford University Press, ISBN 0-19-217571-8 <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li>
<li id="fn:12"><p>(Levy & O'Connell 1981:9) - Levy, David; O'Connell, Kevin (1981), Oxford Encyclopedia of Chess Games, Volume 1 (1485-1866), Oxford University Press, ISBN 0-19-217571-8 <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li>
<li id="fn:13"><p>(Levy & O'Connell 1981:12) - Levy, David; O'Connell, Kevin (1981), Oxford Encyclopedia of Chess Games, Volume 1 (1485-1866), Oxford University Press, ISBN 0-19-217571-8 <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li>
<li id="fn:14"><p>(Reinfeld 1954:175) - Reinfeld, Fred (1954), How To Be A Winner At Chess, Fawcett, ISBN 0-449-91206-X <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li>
<li id="fn:15"><p>(Reinfeld 1958:41–43) - Reinfeld, Fred (1958), Chess in a Nutshell, Pocket <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li>
<li id="fn:16"><p>(Staunton 1847:21) - Staunton, Howard (1847), The Chess-Player's Handbook, London: Henry G. Bohn <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li>
<li id="fn:17"><p>(Hooper & Whyld 1992) - Hooper, David; Whyld, Kenneth (1992), The Oxford Companion to Chess (2nd ed.), Oxford University Press, ISBN 0-19-866164-9 <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li>
</ol>

Perpetual check open-in-new

Perpetual check