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The following position : WHITE King on e2 Bishop on d1 Knight on d2 pawn on f3 BLACK King on d7 Rook on c4 pawn on c5 BLACK to move Is a 7 Pieces endgame indicated as a White win by Syzygy 7 Pieces tablebases. In a blitz game , though , the game ended in a draw from there , although White was Leela zero. Is Leela zero still week in the endgame?

Stefano
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    Please supply the position as a replayer. See https://chess.meta.stackexchange.com/questions/179/how-do-i-add-a-replayer-to-my-post – Ian Bush Aug 10 '23 at 16:55
  • Please precise what blitz game it was : is it a tournament or something you run on your own computer ? What time control ? Which opponent ? Which access to tablebases ? – Evargalo Aug 11 '23 at 14:36

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As far as I can tell, the latest update in regards to tablebases is from August 2018.

The support in v0.17.0 is partial only, only WDL tables are probed, but not DTZ. That means, that Leela is only able to query tablebase for positions immediately after captures and pawn moves, and for other positions it has to think by itself.

While it improves strength of the play in average, often lack of DTZ queries causes weird endgame playing effects and losing play.

For example, Leela may have a 7-men position with considerable advantage (probability of win 99%) and then “simplify” to 6-men “won” position by just giving up the material. That 6-men position is “won” from the point of view of tablebases, so it has probability of win 100%, and Leela happily goes there. However, after that move Leela has to play by itself, and that position may be really hard for Leela to win without tablebases. It’s not rare that that leads to drawn or lost games, which Leela would win or draw if it played without tablebases at all.

From your observation, it appears that Leela Zero is still relying on its own evaluations for the bulk of the endgame. That doesn't necessarily mean that it is weak in the endgame, just that it does not play the positions perfectly and is thus susceptible to losing against engines which do use the the tablebases for endgame play. However, as explained in the last paragraph above, the partial reliance on the tablebases can lead Leela into positions that are theoretically best if the specific sequence of moves is played, but if those moves are difficult to find, it may not be the best path to go down.

Nelson O
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