Wednesday, November 11, 2015

Season 8 superfinal, games 1-10

The Komodo-Stockfish season 8 superfinal has started !! After a week's holiday and a few delays it is finally here: 100 games at time control of 3 hours per engine, on a new fast 24-core machine with a huge RAM, and with access to 6-man tablebases. Both engines have new versions which should be even better than before. Hopefully Stockfish will not have time problems - as a precaution it is running with a full second overhead.

After 10 games Komodo is ahead by 1 win, with 9 draws.

The first 10 games were much quicker than anybody anticipated, I predicted many games would be more than 6 hours long but so far many draws were quite short. In the games so far it seems that both engines see a draw from a mile away and converge to it together with zero evals. The games stop around move 40 by adjudication, or earlier by repetition. 

The final started with a Komodo win in game 1 and a quick draw in game 2. More on this below. Also see this video analyzing game 1 by kingscrusher. However, the next 8 games were draws, mostly boring. This is going to be a long match and exciting games may be a rare bonus.

The opening position for games 1 and 2 had black with two pawns up and white with open files on the king side for immediate attack. Surprisingly for such an unbalanced position, both evals were 0. In fact Komodo was expecting a very short game ending in repetition and this was indeed the result of game 2. In game 1 Stockfish chose to play on. After move 20 Komodo was two pawns behind but it had a strong center and black's king was still uncastled and vulnerable. Komodo had a small eval advantage but Stockfish still felt safe.

The black king moved, giving up on the chance of castling. a few moves later the white center was even stronger, only one pawn down but with evals shooing upwards over 1 for both engines.

 Stockfish tried to defend, exchanging queens and giving a rook for a knight. The situation was becoming hopeless. With the king vulnerable to attack and white having pawns on the sixth row both engines saw the win coming.

It was an easy win for Komodo from here.

Games 3 and 4 were both quite boring, evals were never far from 0 and both engines played with a draw in mind.

Game 5 started with an advantage for white, but it quickly disappeared to zero again. Here Stockfish as black had an extra pawn, a passed pawn too, but did not have the strength to move it forward safely. The reverse game had even less action, but it was fast with a repetition end after 30 moves.

Game 7 reached a rook ending by move 25 and a drawn tablebase position on move 50. Game 8 was a different matter altogether. Komodo's queen took an unguarded g pawn just a few moves after the 8-move book and Stockfish's eval jumped. Was this a case of a poisoned pawn?

A few moves later black's queen escaped but Stockfish prepared an attack on the king side and had an eval of about 1. Would this be a win for Stockfish?

White sacrificed two rooks and a knight for black's queen and shattering the king's position, Komodo remained cool with a rather low eval.

The momentum of the attack was mostly over. Stockfish regained some material but it was left with only the queen and pawns against a RBN combination.

It took a while but eventually Stockfish lowered its eval and recognized it couldn't win. A good effort though.

In game 9 all the heavy pieces were off before move 20. The play continued in absolute equality ending in a tablebase position. There was a little more action in game 10, the pieces stayed on longer and the evals were non-zero for a bit, but the RB vs RB endgame was again a draw.

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