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Garvinator
22-02-2008, 01:14 AM
Dear Sir, Please answer the following question: A player is about to give mate on his next move (the opponent cannot avoid being mated no matter what he does). However, the flag falls of the player who is about to give mate and the opponent claims a win. Who wins in this situation? With Regards, Haroon Or Rashid (Bangladesh)

Geurt's answer: If I understand you correctly, you refer to a situation similar to the following diagram: (I cant put up the diagram- Garvin)

White is on move, and must play Qxb2#, but he oversteps the time before executing his move. Black claims a win on time and White claims he had a forced win. Here we have to apply Article 6.10:

Except where Articles 5.1 or one of the Articles 5.2 (a), (b) and (c) apply, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by the player. However, the game is drawn, if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves, even with the most unskilled counterplay.

Thus, even though White overstepped the time, it is a draw, because Black can never win in this position. Your question reminded me of a position that was discussed in the December 2004 column: http://www.chesscafe.com/text/geurt81.pdf

The game continues: 1…Qc1+ 2.Qxc1+ Qxc1+ 3.Qxc1+ Qxc1+, when White’s flag falls. However, the game is not won for Black, because after the forced 4.Kxc1, it is stalemate. Again, if it is clear that the position is such that the opponent (in this case Black) cannot checkmate the player’s king by any possible series of legal moves, even with the most unskilled counterplay.

Does Geurt's answer seem right to you. I am not so sure and certainly want to hear from others.

Capablanca-Fan
22-02-2008, 02:27 AM
Does Geurt's answer seem right to you. I am not so sure and certainly want to hear from others.
Gijssen's answer does seem to accord with the rules as written, which makes a pleasant change.

Kevin Bonham
22-02-2008, 10:42 AM
I am not quite sure if Geurt has interpreted the question correctly. The questioner only says that the opponent cannot avoid mate whatever he does - on my reading that leaves open the possibility that the player whose flag falls did not have to force the mate.

However if Geurt has interpreted the question correctly (ie all possible sequences of legal moves result in mate by the player whose flag is down) then his answer is correct.

Some people have found that a bit odd, and tried to argue that if a player's flag falls in a situation where they can only mathematically win that they should be declared to have won the game (just as if your flag falls when you cannot lose you get a draw.)

But firstly, that's not what the current rules say, and secondly, saving players from losing on time in unlosable positions is one thing, but why should a player get a win if their flag has fallen before they can play it on the board?

Aaron Guthrie
22-02-2008, 11:26 AM
I am not quite sure if Geurt has interpreted the question correctly. The questioner only says that the opponent cannot avoid mate whatever he does - on my reading that leaves open the possibility that the player whose flag falls did not have to force the mate. Isn't the answer in this case draw too?

Capablanca-Fan
22-02-2008, 11:59 AM
Isn't the answer in this case draw too?
No, because even if the player whose flag dropped has a forced mate (i.e. best play by his opponent can't stop it), there may still be sequence of possible legal moves that would end in this player being mated.

Aaron Guthrie
22-02-2008, 01:37 PM
No, because even if the player whose flag dropped has a forced mate (i.e. best play by his opponent can't stop it), there may still be sequence of possible legal moves that would end in this player being mated.For some reason I was reading that as though only one side could mate. Now I see that was wrong.

Denis_Jessop
22-02-2008, 03:29 PM
I am not quite sure if Geurt has interpreted the question correctly. The questioner only says that the opponent cannot avoid mate whatever he does - on my reading that leaves open the possibility that the player whose flag falls did not have to force the mate.

However if Geurt has interpreted the question correctly (ie all possible sequences of legal moves result in mate by the player whose flag is down) then his answer is correct.

Some people have found that a bit odd, and tried to argue that if a player's flag falls in a situation where they can only mathematically win that they should be declared to have won the game (just as if your flag falls when you cannot lose you get a draw.)

But firstly, that's not what the current rules say, and secondly, saving players from losing on time in unlosable positions is one thing, but why should a player get a win if their flag has fallen before they can play it on the board?

Certainly the question, as put, is rather vague and it is not clear what sort of position the questioner has in mind. Geurt realises this in his opening words "If I understand you correctly..."

Equally, in the position Geurt refers to, he is clearly right as W is to move when his flag falls and W's only legal move is Qxb2#. Thus the reference in Art.5 to the opponent not being able to checkmate the player (= the player whose flag has fallen) is clearly fulfilled as after W's next move, the opponent will have no legal move available.

Still, it's not clear that the position cited by Geurt is what the questioner had in mind. The answer may be "wait for the next thrilling episode".

DJ