Is that a new rule? I was under the impression that it had been the case for a very long time that if you went out on time but there was no possible sequence of moves leading to checkmating you, it was a draw instead. (Meaning, of course, that having more pieces could be a disadvantage in such situations, which feels a bit unfair. E.g., KvKB is a draw, but KPvKB can lead to a mate if both sides cooperate, and thus would be a time loss for white even if black would never win in practical play.)

▲ qsort 8 hours ago | parent | next [-]

That's not new, but how it formally works has changed. There used to be a number of explicitly enumerated cases (i.e. bare king and king with a minor piece,) now the rule instead just says that there must exist a sequence of moves to mate. Some positions, even with pawns (imagine a completely closed position with only pawns and kings) wouldn't have been automatically drawn under the previous system but now would be. I think USCF rules, unlike FIDE, still have the enumerated cases?

The difference is extremely minor and has almost no strategic implications, it's just an interesting corner case.

▲ Sesse__ 43 minutes ago | parent | next [-]

The oldest rules on FIDE's pages are the ones for “before 2014”. They state:

  The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was legal. (See Article 9.6)

And 9.6 just states:

  The game is drawn when a position is reached from which a checkmate cannot occur by any possible series of legal moves. This immediately ends the game, provided that the move producing this position was legal.

And similarly 6.9, which governs loss on time:

  Except where one of the Articles: 5.1.a, 5.1.b, 5.2.a, 5.2.b, 5.2.c applies, 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.

So it's at least ten years old, but possibly quite more. I know I have a copy of the 1984 rules (or possibly even older) somewhere on paper, but then I'd have to go into the attic :-)

▲ TZubiri 6 hours ago | parent | prev [-]

Does it depend on elo as well?

	▲	lmm an hour ago \| parent [-]
		No. How could it possibly depend on elo?

▲ jmount 8 hours ago | parent | prev [-]

I just updated the article. I did use Python's insufficient material detection, in addition to the ability to call for a draw (3-fold repetition, and 50 move rule). I think the "75 move rule" that doesn't require a player to call is one of the more recent rule changes.