I don't believe the tablesbases are linked to any of the engines yet, just available on the game tab when a position is reached with few enough pieces.
Syzygy not choosing shortest path for mate ?
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Sep 20, 2022
0
#23
@Martin_Stahl
But the chess.com GUI should be fixed.
It's almost certainly sending SF15 the FEN after 34B in my preceding example.
That's not enough for SF15 to work on. The FEN after 34B in the mainline (draw) is identical to the FEN after 34B in the variation (mate in 16).
After 34B instead of (if it's UCI) sending
position fen 8/8/8/8/3k4/8/1R6/K7 w - - 68 35
it needs to send (e.g. for the variation)
position fen 7k/8/8/8/8/8/1R6/1K6 w - - 0 1 moves b1a1 h8h7 ... c3d3
and similarly for all positions. (It needs to send only the moves from the last ply count 0 position.)
If it doesn't SF's returned evaluations may be substandard and chess.com/sf15's play may be substandard as a result.
Hello all,
I entered the QR Philidor endgame in my droidfish/syzygy configuration for analyzing,
(FEN : 1k6/1r6/2K5/Q7/8/8/8/8 w - - 0 1) and I got the following information :
[175] m10 Qd5 Ka8 Qg8+ Ka7 Qd8 Rh7 Qd4+ Kb8 Qe5+
Ka7 Qa1+ Kb8 Qb1+ Ka7 Qxh7+ Ka6 Qb7+ Ka5 Qb5#
d:176/20 3:Qg5 t:9599 n:4866M nps:506k tb:24 h:100
I think most of information is pretty self-explanatory,
but does anyone know what the following means :
[175] ?
d:176/20 ?
h:100 ?
I don't understand much the symbols/numbers for this position
which is 10 moves from checkmate
Thank you
Jan 13, 2023
0
#25
MARattigan wrote:
@Martin_Stahl
But the chess.com GUI should be fixed.
It's almost certainly sending SF15 the FEN after 34B in my preceding example.
That's not enough for SF15 to work on. The FEN after 34B in the mainline (draw) is identical to the FEN after 34B in the variation (mate in 16).
After 34B instead of (if it's UCI) sending
position fen 8/8/8/8/3k4/8/1R6/K7 w - - 68 35
it needs to send (e.g. for the variation)
position fen 7k/8/8/8/8/8/1R6/1K6 w - - 0 1 moves b1a1 h8h7 ... c3d3
and similarly for all positions. (It needs to send only the moves from the last ply count 0 position.)
If it doesn't SF's returned evaluations may be substandard and chess.com/sf15's play may be substandard as a result.
I'm afraid that appears to be at least partly nonsense.
There seems also to be a flaw in Stockfish. I thought from conversations the developers had online that it had been fixed, but it's not not in my version at any rate.
I tried giving it the ply count 0 FEN plus the moves in the following from the command line.
Black's only good continuation is 32...Ka1 which draws, but my Stockfish 15 recommends 32...Kc1 which loses (as, of course, do the tablebases).
Stockfish 15 plays 32...Kc1 in Arena and Tarrasch (as well as the chess.com GUI).
StockFish - at least as implemented on chess.com - has the habit of favoring repeat moves to see if you are willing to make a mistake that allows a faster(?) or safer(?) win. As SF is in control of the game we don't know how and when it interfaces to syzygy. It might have retained some of its human "I know better" character
SF as implemented on chess.com doesn't appear to interface to Syzygy at all (try practice against computer in a KNNKP White to win in > 36 position).
Otherwise SF does still search once it reaches a tablebase position when Syzygy is connected, but that's mainly so it doesn't take 108 moves over a mate in 2 and look stupid. It limits the search to winning moves and I don't believe it will repeat positions once it reaches the tablebase.
Before it reaches Syzygy, or without Syzygy, it will repeat moves whether it thinks it is winning or losing, but that's only if the repeated position evaluates better than its alternatives; I don't think it's an indication of sentience creeping into the Superficial Intelligence. It has bail out code to avoid a triple repetition if it thinks it's winning.
The chess.com GUI is flawed in that respect. If you try letting it play from move 35 onwards in the variation in the example I posted earlier (below), which is mate in 16 at that point, it draws in 1 move because of the flaw. The play shown is against Tarrasch/SF15. It also draws, but in 10 moves. That's not a flaw in Tarrasch though, it's just that Stockfish can't play the KPvK endgame.
Syzygy uses only the FEN without ply count, move number and castling rights to rank it's moves. It can't be said to recommend a move in positions where a top ranked move has not been selected for a winning side in all positions from the ply count 0 position in the endgame. But the Tarrasch/SF15 play above illustrates that SF may ignore the Syzygy ranking if it has information on preceding play in that case. (The Syzygy top ranked move after move 34 would also draw in 1).