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Edit - I suppose it is a draw rather than a stalemate Fide Rules 5.2 (B) The game is drawn when a position has arisen in which neither player can checkmate th

by oli5679 10y ago

Edit - I suppose it is a draw rather than a stalemate Fide Rules 5.2 (B) 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)

mikeash 10y ago
Oh yes, I was thinking of a case where checkmate is theoretically possible, but where your opponent can thwart it indefinitely with good play. But as you say, that's a draw rather than a stalemate. Which is not a particularly important distinction, I will admit!
- oli5679 10y ago
  No worries.. Programming all the draw scenarios in chess wouldn't be completely trivial. If you add clocks to the game then you also need to account for when you flag but your opponent cannot win the game with legal moves. There are some strange edge-cases here for pawns vs minor pieces. Example: https://www.chess.com/forum/view/livechess/draw-by-insufficient-material2 https://www.chess.com/forum/view/livechess/draw-by-insuffici...
- Scarblac 10y ago
  The starting position is probably "a case where checkmate is theoretically possible, but where your opponent can thwart it indefinitely with good play".
  - mikeash 10y ago
    Heh, indeed. I think what I meant was that your opponent can thwart it, in practice, given the actual abilities of both players. Things like the 50 move rule and the repetition rule are ways to detect this condition without actually having to figure out a way to analyze their abilities to decide whether a position is practically unwinnable.
Scarblac 10y ago
Yes, that one is quite hard to get right for normal chess engines too, and it usually isn't done. E.g. if both sides have only a bishop left, then if the two bishops are on squares of the same color checkmate isn't possible, but if they are on different colors then checkmate is possible in a corner. Or pawn formations in the middle of the board that prevent breakthroughs. Most online chess sites only consider the obvious case of king + bishop or knight vs king to be a draw under that rule (and king v king, obviously).

by oli5679 10y ago

mikeash 10y ago

Oh yes, I was thinking of a case where checkmate is theoretically possible, but where your opponent can thwart it indefinitely with good play. But as you say, that's a draw rather than a stalemate. Which is not a particularly important distinction, I will admit!

oli5679 10y ago
No worries.. Programming all the draw scenarios in chess wouldn't be completely trivial. If you add clocks to the game then you also need to account for when you flag but your opponent cannot win the game with legal moves. There are some strange edge-cases here for pawns vs minor pieces. Example: https://www.chess.com/forum/view/livechess/draw-by-insufficient-material2 https://www.chess.com/forum/view/livechess/draw-by-insuffici...
Scarblac 10y ago
The starting position is probably "a case where checkmate is theoretically possible, but where your opponent can thwart it indefinitely with good play".
- mikeash 10y ago
  Heh, indeed. I think what I meant was that your opponent can thwart it, in practice, given the actual abilities of both players. Things like the 50 move rule and the repetition rule are ways to detect this condition without actually having to figure out a way to analyze their abilities to decide whether a position is practically unwinnable.

Scarblac 10y ago

Yes, that one is quite hard to get right for normal chess engines too, and it usually isn't done. E.g. if both sides have only a bishop left, then if the two bishops are on squares of the same color checkmate isn't possible, but if they are on different colors then checkmate is possible in a corner. Or pawn formations in the middle of the board that prevent breakthroughs. Most online chess sites only consider the obvious case of king + bishop or knight vs king to be a draw under that rule (and king v king, obviously).