In a sudden death time control, White claims a win on time simultaneously as Black claims White’s last move was illegal. What is the correct resolution and why?
I would rule on the illegal move claim first, if that is upheld, the win on time claim may not longer be valid.
Checkmate can only be legitimately claimed if the last move was legal, and is otherwise reversed. It seems feasible to handle flag claims the same way.
This case is explicitly dealt with in the blitz rules at 7e:
7e.) An illegal move doesn’t negate a player’s right to claim on time, provided it is made prior to the opponent’s claim of an illegal move. If the claims are simultaneous, the player who made the illegal move loses.
Which is consistent with claims of checkmate / stalemate simultaneously with claims on time, in 13A3 and 14A3:
13A3. Unclear if checkmate or flag fall came first.
After considering all available evidence, including testimony by the players and any witnesses, a director who is still unable to decide whether the claim of the flag fall occurred first shall deny the time claim and rule the checkmate valid.
14A3. Unclear if stalemate or flag came first.
After considering all available evidence, including testimony by the players and any witnesses, a director who is unable to determine whether the flag fall occurred first shall deny the time claim and uphold the stalemate.
I take the principle to be that, whenever you have a simultaneous claim including a claim of time, the time claim loses.
In general, the time claim probably does not get precedence over other claims, but there may be situations in which the time claim might get precedence, such as player A claims a win on time while player B produces a legal checkmate, if there is sufficient evidence that the flag fell first. (A digital clock that freezes when a player’s time expires might not be sufficient evidence, one of the reasons I’m not fond of that feature.)
But that was not the situation the OP presented.
Thank you all
It was a very interesting discussion between a group of friends. The situation almost happened but I wasn’t there or TD when it almost happened. We figured getting some clarification before it happened again would help.
Would it matter if the flag fall claim was made first ? The OP mentions they are simultaneous.
If not, how long does the illegal move claimant have to make their claim?
Not sure the rulebook offers much guidance here.
I usually handle claims in the order in which they are made. But if person A says “His flag has fallen” and person B quickly responds “His last move was illegal” that gets messy. If I’m a witness to the incident then I would go by what I saw, such as if I saw the illegal move made and then the flag fall.
But that opens up the interventionist vs non-interventionist issue.
If I see an illegal move made while I"m watching a game in time trouble, is it my responsibility to point it out or the opponent’s responsibility to claim it?
What about if I’m just walking down the aisle and I see an illegal move made?
The ‘right’ thing to do might depend on the specific circumstances.
As Underdog would say, “Nobody said it would be easy, Fred.”
For USCF the answer is clear, assuming you mean “time pressure”:
11D1. Illegal move in time pressure.
Time pressure is defined as a situation where either player has less than five minutes left in a time control and the time control does not include an increment or delay of 30 seconds or more. A director should not call attention to illegal moves in time pressure, only the players may make that claim.