Editing Perpetual check (section)

==Examples==
{{Chess diagram
|tright
|Example from Reinfeld
|  |  |  |  |  |  |kd|  
|  |  |  |  |  |  |pd|  
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |kl|ql
|  |rd|  |  |  |  |  |  
|qd|  |  |bd|  |  |  |  
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |  |  
|White to move draws by perpetual check, starting with 1.Qe8+.
}}
In this diagram, Black is ahead a [[Rook (chess)|rook]], a [[bishop (chess)|bishop]], and a [[pawn (chess)|pawn]], which would normally be a decisive {{chessgloss|material}} advantage. But White, to move, can draw by perpetual check:
: '''1. Qe8+ Kh7'''
: '''2. Qh5+ Kg8'''
: '''3. Qe8+''' etc.<ref>{{Harvcol|Reinfeld|1958|pp=42–43}}</ref>
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. 
{{clear}}

===Unzicker vs. Averbakh===
{{Chess diagram
|tright
|Unzicker vs. Averbakh, 1952
|  |  |  |  |  |rd|kd|  
|  |rd|pl|  |  |  |pd|pd
|pd|  |  |  |  |nd|  |  
|  |  |  |pl|pd|  |  |  
|  |pl|  |  |pl|qd|  |  
|  |  |ql|  |  |  |  |pl
|pl|  |  |  |  |  |pl|  
|rl|  |  |  |rl|  |kl|  
|Perpetual check extricates Black from his difficulties.
}}
In the diagram, from [[Wolfgang Unzicker]]–[[Yuri Averbakh]], Stockholm [[Interzonal]] 1952,<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1153024 |title=Unzicker vs. Averbakh, Stockholm 1952 |website=[[Chessgames.com]] }}</ref> Black (on move) would soon be forced to give up one of his [[rook (chess)|rooks]] for White's c-[[pawn (chess)|pawn]] (to prevent it from [[promotion (chess)|promoting]] or to capture the promoted [[queen (chess)|queen]] after promotion). He can, however, exploit the weakness of White's {{chessgloss|kingside}} [[pawn structure]] with 
:'''27... Rxc7{{chesspunc|!}}'''
:'''28. Qxc7 Ng4!''' 
Threatening 29...Qh2{{chessAN|#}}. If 29.hxg4 then 29...Qf2+, salvaging a draw by threefold repetition with checks by moving the queen alternatively to f2 and h4.
{{clear}}

===Hamppe vs. Meitner===
{{Main|Immortal Draw}}
{{Chess diagram
|tright
|Hamppe vs. Meitner, 1872
|rd|  |bd|kd|  |  |  |rd
|  |  |pd|  |  |pd|pd|pd
|  |pd|kl|  |  |  |  |  
|pd|  |  |pd|pd|  |  |  
|  |  |  |  |  |  |  |  
|pl|  |  |  |  |  |  |  
|  |pl|pl|pl|  |  |pl|pl
|rl|  |bl|ql|  |  |nl|rl
|Down massive amounts of material, Black forces a draw by perpetual check.
}}
In a classic game [[Carl Hamppe]]–[[Philipp Meitner]], Vienna 1872,<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1250160 |title=Hamppe vs. Meitner, Vienna 1872 |website=[[Chessgames.com]] }}</ref> following a series of [[sacrifice (chess)|sacrifices]] Black forced the game to the position in the diagram, where he drew by a perpetual check: 
:'''16... Bb7+!'''
:'''17. Kb5''' 
If 17.Kxb7{{chesspunc|??}} Kd7 18.Qg4+ Kd6 followed by ...Rhb8#.
:'''17... Ba6+'''
:'''18. Kc6''' 
If 18.Ka4{{chesspunc|?}}, 18...Bc4 and 19...b5#.
:'''18... Bb7+ {{chessAN|½–½}}'''
{{clear}}

===Leko vs. Kramnik===
{{Chess diagram
|tright
|Leko vs. Kramnik, 2008
|rd|  |  |  |  |  |  |kd
|pd|pd|  |  |  |  |pd|pd
|  |  |pd|  |  |  |  |  
|  |  |  |  |  |ql|  |  
|  |  |  |  |  |  |  |pl
|  |  |qd|  |  |  |  |  
|  |  |pl|  |  |pl|pl|  
|  |kl|  |rl|  |  |  |rl
|Position after 24.Qxf5
}}
In the game [[Peter Leko]]–[[Vladimir Kramnik]], [[Corus chess tournament|Corus]] 2008, Black was able to obtain a draw because of perpetual check:<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1482384 |title=Leko vs. Kramnik, Wijk aan Zee 2008 |website=[[Chessgames.com]] }}</ref>
:'''24... Qb4+'''
:'''25. Ka2 Qa4+'''
:'''26. Kb2 Qb4+'''
:'''27. Kc1 Qa3+'''
:'''28. Kb1 ½–½'''
If 28.Kd2? Rd8+ 29.Ke2 Qe7+.
{{clear}}

===Fischer vs. Tal===
{| align="right" 
|-valign="top" 
|+
|
[[File:Bundesarchiv Bild 183-76052-0335, Schacholympiade, Tal (UdSSR) gegen Fischer (USA).jpg|thumb|right|upright=0.90|Fischer vs. Tal, 1960]]
|
{{Chess diagram  
|tright
|
|  |  |kd|  |  |  |  |  
|pd|pd|  |  |nd|  |  |ql
|  |  |  |  |qd|  |  |  
|pl|  |  |pd|  |  |  |  
|  |  |  |  |  |  |  |  
|pl|  |pd|  |  |  |  |  
|  |  |pl|  |  |pl|kl|pl
|  |  |  |  |  |rl|  |  
|Position after 21.Kxg2
}}
|}
A perpetual check saved a draw for [[Mikhail Tal]] in the game [[Bobby Fischer]]–Tal, Leipzig 1960,<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1008399 |title=Fischer vs. Tal, Leipzig 1960 |website=[[Chessgames.com]] }}</ref> played in the [[14th Chess Olympiad]], while Tal was [[World Chess Championship|World Champion]].  In this position Black played 
:{{pad}}'''21... Qg4+''' 
and the game was drawn.<ref>{{Harvcol|Evans|1970|p=53}}</ref>  (After 22.Kh1, then 22...Qf3+ 23.Kg1 Qg4+ forces perpetual check.)
{{clear}}