2 ms·
Is that 59 ply? 59 moves without a pawn move or capture means the game was drawn nine moves ago. Here's what's confusing me: if the chess engine has an initial
by gweinberg 5y ago
Is that 59 ply? 59 moves without a pawn move or capture means the game was drawn nine moves ago.
Here's what's confusing me: if the chess engine has an initial numeric value for the current position, and the positions going out to the end of its search all have the same value or worse, shouldn't it be pretty trivial to conclude it is not making progress?
- shric 5y agoYes, I guess Stockfish doesn't bother to consider a draw on the 50 move rule. It does, iirc, go for a draw if it has no better via threefold repetition.
- perihelions 5y agoStockfish does plan around the 50-move rule. Here's a quick demo (it is silly): https://lichess.org/analysis/8/1p3K2/kPp5/2P5/2P5/1p6/1P1Q4/8_w_-_-_98_1 https://lichess.org/analysis/8/1p3K2/kPp5/2P5/2P5/1p6/1P1Q4/... It's not visible on the board itself, but this position's 50-move rule counter is set to 98 ply -- two ply short of a draw. (That's the 2nd-to-last-field in the FEN representation -- the editable text field just below the board, and also in the URL). The only way to avoid that draw, as Stockfish does in fact suggest, is to a sacrifice a piece in a specific and ridiculous way, to compel black to re-capture on the 100th ply (captures reset the 50-move rule). If you edit the 50-move counter down, Stockfish instead shows you the simple mate-in-3. Nakamura famously tricked a different chess engine, relying on this 50-move draw avoidance (as one component of the hack) -- a sibling thread is discussing that example: https://news.ycombinator.com/item?id=27189718 https://news.ycombinator.com/item?id=27189718