Thursday, November 5, 2015

Season 6 superfinal, games 1-8

I sometimes think about going over the TCEC archive to look back at the games, look for special gems, relive the excitement. Anyway, since we're waiting for the superfinal of season 8 and there is a break of over a week, I thought I'll give it a go. I chose to start with the season 6 superfinal between Stockfish and Komodo. This was the season where Stockfish was the most dominant, winning its first (and only so far) TCEC title.

The format was 32 openings, each played in reverse color pairs, time control was 2 hours per engine and the usual 30 second increment.

Game 1
Link to TCEC archive

The opening favored white,  black had open files to attack on the king side but the blocked center made it hard to maneuver. White had more space and could attack on the queen side since black chose to castle long.

Stockfish's eval advantage gradually increased after Komodo decided to give a rook for a bishop and started to play defensively.

The pressure on the queen side increased and after a series of pins and threats the knights were exchanged. Could Komodo hold the position?

At this point Komodo made what seems to me as the crucial mistake. It decided to go after the b5 pawn, ignoring the king side. Stockfish saw this and immediately sent the passed h pawn forward.

Komodo had to give up the pawns in the center to stop the h pawn, and after queens were exchanged Komodo couldn't stop the remaining white pawns without losing material.

In the reverse game Stockfish chose to exchange queens early and not to castle at all. Komodo managed to get two connected passed pawns on the king side but Stockfish built an effective blockade defense and the game ended in a draw. Stockfish in the lead after first opening !!

The next two games were quick draws, both ending in 3-fold repetition. Game 5 was also a draw, reaching a rook endgame by move 27 and a tablebase position on move 43. In the reverse game Komodo held on to an eval advantage for a bit longer but Stockfish defended well until almost all pieces were removed. In the ending of B vs N Komodo sacrificed the bishop for two pawns, then both sides queened, but it was still a draw.

In game 7 Stockfish gave the illusion it had an advantage, but after two long stretches of shuffling the position opened up and the advantage slowly grew smaller, until there were almost no pieces in a tablebase draw. 

Game 8
Link to TCEC archive

Komodo started with a small eval advantage in the reverse game, with Stockfish giving a rook for a knight early on. However once the queens were exchanged the evals became drawish.

As the game progressed Stockfish started to get better. The black knights were much more effective in a closed position than either rooks or the white bishop.

Komodo found it harder and harder to move while Stockfish arranged its pieces for an optimal pawn advance.

When the break finally came Stockfish had a huge eval advantage. Komodo gave its useless bishop for a pawn but could not untangle itself. Once a pair of rooks was exchanged the black knights became too strong and the game was over.

Stockfish up 2 (6 draws) after 8 games, still a long way to go.

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