Talk:Perpetual check

message: I must have lost a point somehere, but isn't the knight on g5 ? How can it jump to g4 ? Is there aomething wrong somewhere ? (if what's wrong is in my head, I'd be glad to know what... ^^;; )
:someone changed the diagram  Arvindn 19:39, 14 Oct 2004 (UTC)
thread_title: old talk

message: I have been Googling for a while and haven't found anything saying that "perpetual check used to be in the laws of chess".  The best I could find was a mention by Staunton that it is a special case of the threefold repetition rule (which is the same status perpetual check has now - a tactic, not an independent drawing method).  However, I haven't found a citable source saying there was never such a rule (just a lot of forum posts).  I don't discount that whoever said there used to be a perpetual-check rule might have had some basis for saying that, so I am asking for a source citation.JoeJust 21:49, 22 March 2007 (UTC)
replies: text: Official Chess Rulebook by Kenneth Harkness, 1970, page 46, says ...commonly known as the draw "by repetition of moves."  It includes perpetual check but it doesn't specifically list perpetual check.  However, the way it is worded seems to imply that there had been a perpetual check rule.  I'll look for older rulebooks.  Bubba73 (talk), 22:16, 22 March 2007 (UTC)
replies: text:  I finally found a book old enough to have the perpetual check rule - a 1954 Reinfeld book.  Citation added to article.  Bubba73 (talk), 00:36, 3 April 2007 (UTC)

text: I'll rephrase it slightly.  But it is a verfyable statement from a WP:RS.  Bubba73 (talk), 15:29, 4 June 2007 (UTC)
replies: text:  I've ordered a copy of Kenneth Harkness's 1967 rulebook to see what it says.  And note that above, someone told me that his 1951 rulebook says the old rule covering draw by perpetual check has been abandoned. A player who can subject his opponent's King to an endless series of checks can force a third repetition of the position and claim the draw. .  Bubba73 (talk), 03:46, 7 June 2007 (UTC)

text:  Now there is also the reference from Staunton.  That sufficies for references. Bubba73 (talk), 14:46, 9 June 2007 (UTC)
replies: text:  It would be interesting to hear thge justification for removing the rule.  I suspect that someone on the rules commitee raised the question of "How can one prove that something is 'endless' in a finite period of time?"  It may be obvious to anyone and everyone, but proven?  Not in the strict mathematical or logical sense.  So, they let it go, as there was no practical effect: the draw would eventually be confirmed by one of the other rules. WHPratt (talk) 16:25, 9 February 2010 (UTC)
replies: text:  I think you must be right about that.  In some cases perpetual check is obvious - in others it isn't so clear and there could potentially be a way out.  The objective threefold and fifty-move rules will eventually be used, or a draw by agreement.  I think that the FIDE rules committee wanted to make everything objective - no judging necessary.  I think this applied to when a player's time runs out too.  In FIDE rules, if one player's time runs out, the other must possibly be able to checkmate in order to win.  In the case of Monica Socko it got down to K&N vs. K&N when one person's time expired.  Checkmate is possible but the opponent has to help!  They initially ruled a draw, but by the rules it was changed to a win.  But no judgment is needed.  Instead, the USCF has the "insufficient losing chances" rule, which makes more sense - except that it requires a judgement. Bubba73 (You talkin' to me?), 18:04, 9 February 2010 (UTC)
thread_title:  historical perpetual-check rule 

message: The article gives a slightly erroneous impression about this game, actually White's best outcome is a draw following 12.Kxc5 (moves following that other than those actually played lead to material disadvantage [13.Qg4?] or mate [14.Be8?? etc.]). As written in the article and in the caption for the position it seems to be implied that Black just manages to salvage a draw after White's 16th move. Mallocks 15:41, 19 September 2007 (UTC)
replies: text: That was added by user:Krakatoa on Oct 28, 2006.  Bubba73 (talk), 19:14, 19 September 2007 (UTC)
replies: text: I've toned down the sheer amount of excited commenting but I'm still dubious as to whether the game should be included at all. Certainly it's beautifully played but the perpetual check at the end is just about the least exciting bit about it, so I question the particular relevence. Mallocks 11:03, 20 September 2007 (UTC)
replies: text:  Well, it does illustrate a perpetual check, so I'm in favor of keeping it.  Bubba73 (talk), 15:47, 20 September 2007 (UTC)
replies: text: I've tried to clear it up. Mallocks 17:19, 20 September 2007 (UTC)
thread_title:  Hamppe-Meitner 

message: The example pic with the queen is wrong. The black king can block with a pawn move to G6, stopping perpetual check. The pic needs to be altered/removed/replaced.  —Preceding unsigned comment added by 24.4.178.155 (talk) 03:41, 8 December 2007 (UTC)
thread_title: Examples

message: I cut this example from the article:
:In the second position, Black draws by giving perpetual check:
:: 1... Qa1+!
:: 2. Kd3 Qd1+
:: 3. Ke3 Qg1+!
:: 4. Ke4 Qg4+
:: 5. Kd5 Qd7+
:: 6. Kc5 Qa7+
:: 7. Kc4 Qa4+
:: 8. Kc3 Qa1+, etc.
:By checking on the marked squares (including a4), White has no chance to stop the checks .
This is a draw but not necessarily a draw by perpetual check; white can avoid the checks and still draw the game by a sequence like this:
: 1... Qa1+
: 2. Kc2 Qxd4
: 3. g8=Q
You can confirm this by entering the original position (8/6P1/8/8/q2Q4/2K5/8/7k b - - 0 0) to the Nalimov Tablebase server. Gdr 19:47, 26 September 2008 (UTC)
replies: text: Yea, well... White either has to give in to a perpetual check or give away his queen, and obviously he doesn't want to do that.  Remember it is Black that is trying to draw, not White.  Bubba73 (talk), 05:07, 27 September 2008 (UTC)

text: I'll look up some precise definitions later and see,  But here White can escape the perpetual check by giving up his queen.  But since White wants to play for a win, he obviously doesn't want to do that.  Bubba73 (talk), 16:20, 27 September 2008 (UTC)
replies: text:  The Oxford Companion to Chess simply says "an unstoppable series of checks usually instigated to avoid loss of the game", which doesn't clear it up.  Golombek's Encyclopedia isn't any more helpful.  But I think it is implied that if he has to give up his advantage (or even get checkmated) to get out of the perpetual check, it is still basically perpetual check.  Bubba73 (talk), 02:20, 29 September 2008 (UTC)
replies: text:  The only way White can escape the checks is by hanging his queen, resulting in a dead-drawn Q v. Q ending after Black takes White's queen and White promotes her pawn to a new queen.  I think under those circumstances it's reasonable to describe the position as one where Black draws because of perpetual check. Krakatoa (talk) 03:58, 29 September 2008 (UTC)
replies: text:  Yes, in this case I think it is safe to say that the perpetual check forces a draw, one way or the other.  I don't think Black can draw without it.  Bubba73 (talk), 04:55, 29 September 2008 (UTC)

text: For #1, Speelman has a section "Perpetucal check and perpetual attack".  He says "In a sense perpetual check is only one example of perpetual attack - any manoeuvre whereby the weaker side forces the stronger side to repeat a position.  First some examples of perpetual check." Then he gives that position, with the caption "example of perpetual check".  Then he continues "Perpetual check, or the threat of it, is one of the defender's main resources in queen and pawn endgames.  In diagram 60 Black can give perpetual check immediately..." and he gives moves.  "By checking on the squares which mark out the perimeter of a square Black gives White no chance to vary."  He says nothing about giving up the white queen to end the perpetual check.  But even if White does this, Black can either have a perpetual check or force the exchange of queens.  Chess writers make some assumptions about what the reader will understand. Bubba73 (talk), 15:10, 29 September 2008 (UTC)

text: What if we change it to "White cannot stop this series of checks except by giving up his queen." Bubba73 (talk), 15:16, 29 September 2008 (UTC)
thread_title: Example cut: not necessarily perpetual check

message: Moved from the article page:
"This is for anyone who looks at this page, but if I'm not mistaken, when the Queen moves to F5, the pawn at G7 can just move to G6, blocking the Queen and actually preventing perpetual check.  Would anyone like to provide a better example of perpetual check? "
: Black does move the pawn to g6 on his fourth move to stop the checks, but then the white queen captures the pawn on f7 with check, perpetual check.  Perhaps the example should show the pawn already on g6.  Bubba73 (talk), 20:43, 21 January 2009 (UTC)
thread_title:  first example 

message: h in step 3 should be p for pawn--L
:Nope. "P" for pawn is not used in algebraic notation; specifying the starting file as done here is the correct way to notate a pawn capture. Double sharp (talk) 11:30, 5 April 2019 (UTC)
thread_title:   Unzicker versus Averbakh 

message: We should probably give an example of perpetual attack / perpetual pursuit that is not check, come to think of it. A nice study is this one by S. Birnov (1928) given in Seirawan's Winning Chess Tactics). 1.a6 Bxc4 2.e4+! (restricting the bishop to half the diagonal) 2...Kxe4 3.a7 Bd5 4.c4 Ba8 5.Kb8 Bc6 6.Kc7 Ba8 and the perpetual pursuit is achieved. (An immediate 1.e4+? fails to 1...Ke5! 2.a6 Bh7 3.a7 Bxe4 and the pawn is stopped.) Double sharp (talk) 08:56, 2 October 2021 (UTC)
replies: text: (Bilek vs Schussler 1978 is a real-game example.) Double sharp (talk) 12:25, 2 October 2021 (UTC)
replies: text:  I think that is OK.  It probably needs a little explanation of what will happen from there in the 1978 game. Bubba73 You talkin' to me? 16:26, 2 October 2021 (UTC)
replies: text: I added it. Strangely Seirawan and Silman don't attribute the Bilek vs Schussler game, so I should probably find a source for that. Double sharp (talk) 08:53, 5 October 2021 (UTC)
thread_title:  Perpetual pursuit