FIDE rules and the atomic variant

This is an interesting question by my friend. He's a better variants player than me, and I found this question interesting.
Suppose an atomic chess game starts with the following moves:

1.e4 f5, 2.exf5 e6, 3.Qf3 Bb4, 4.Qf7??

lichess.org/analysis/atomic/rnbqk1nr/pppp1Qpp/4p3/8/1b6/8/PPPP1PPP/RNB1KBNR_b_KQkq_-_3_4?color=white

By the rule of atomic chess, the only legal move for black is Bxd2, checkmate. But what if black doesn't know and runs out of time? Then... By the FIDE rules, it would be a draw!

FIDE rule 6.9 (The timed-out player loses.) "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."

Well, black ran out of time, but since black has no other legal moves than Bxd2#, the position is such that white can't checkmate black by any possible series of legal moves. Therefore, draw!

These kind of positions happen quite often in the atomic variant, where the only possible legal move is mate. But apparently lichess still thinks it's a loss for the timed-out player. Are there any official rules for these kind of situations in variants?

I'd be hesitant to apply FIDE's rules for standard chess to variants. Given the lack of official FIDE rules for Atomic, I don't think there's any reason for FIDE to feel a need to conform to it.

Even in standard chess, it's not simple for a computer to adjudicate positions where wins are impossible, so I'm not surprised lichess doesn't do it here.

I don't think variants have official rules

@Yclept said in #1:
> But what if black doesn't know and runs out of time?

Well, then they have 3 minutes or whatever to read lichess.org/variant/atomic which is linked directly from the game page, which says in bold lettering:
Traditional checkmate applies to atomic as well, but any move that results in blowing up the opposite king will result in an immediate victory, overriding all checks and checkmates.

But yeah... determining "forced win" in chess and in variants is difficult, so for the other use case of "I was playing 1-minute and my clock ran out" I would suggest playing with an increment of 1 second or more.

FIDE is not atomic.

@Yclept said in #1:
> This is an interesting question by my friend. He's a better variants player than me, and I found this question interesting.
> Suppose an atomic chess game starts with the following moves:
>
> 1.e4 f5, 2.exf5 e6, 3.Qf3 Bb4, 4.Qf7??
>
> lichess.org/analysis/atomic/rnbqk1nr/pppp1Qpp/4p3/8/1b6/8/PPPP1PPP/RNB1KBNR_b_KQkq_-_3_4?color=white
>
> By the rule of atomic chess, the only legal move for black is Bxd2, checkmate. But what if black doesn't know and runs out of time? Then... By the FIDE rules, it would be a draw!
>
> FIDE rule 6.9 (The timed-out player loses.) "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."
>
> Well, black ran out of time, but since black has no other legal moves than Bxd2#, the position is such that white can't checkmate black by any possible series of legal moves. Therefore, draw!
>
> These kind of positions happen quite often in the atomic variant, where the only possible legal move is mate. But apparently lichess still thinks it's a loss for the timed-out player. Are there any official rules for these kind of situations in variants?

Official rules for variants of chess can vary depending on the specific variant being played. However, in general, the rules for variants are not as well-established as those for traditional chess.

In the case of atomic chess, the situation you described is indeed possible, where the only legal move for the defending side is a checkmate. If the defending side runs out of time in this situation, and the position is such that the attacking side cannot deliver checkmate by any series of legal moves, then it would be considered a draw under FIDE rules.

However, it's important to note that not all chess platforms or organizations may follow these rules for variants, and some may have their own specific rules or interpretations. Therefore, it's always a good idea to check the specific rules and regulations of the platform or organization where you are playing a particular variant.