Friday, December 2, 2016

Season 9 superfinal, games 67-70

After 70 games Stockfish is leading 12-6 with 52 draws. Four of the last 8 games have been decisive, Stockfish's lead remains a constant +6.

After the opening of game 67 Stockfish's eval increased to about 1. There were several early exchanges which left Stockfish a pawn up, Houdini had a bishop pair but the bishop on h5 was close to being trapped.

The evals stayed at this level for quit a while. The complicated position was gradually simplified by exchanges, leading to a RB vs RN ending with Stockfish a pawn up.

Stockfish was a pawn up but with so few pieces on the board the game seemed to be heading for a draw. All the pieces moved toward the top left corner, Houdini's chance to hold was to block the advancing white pawns. Stockfish's eval jumped to 2 and then stayed there for 15 moves, again giving the impression that Houdini can hold.

Suddenly Stockfish saw something and its eval jumped to 9.62. BOOM. WOW !! Unbelievable, what did Stockfish see that Houdini didn't? After a6+ Stockfish quickly drove the king away from the corner leaving the a7 pawn with one less defender. The game was stopped a few moves before Stockfish was able to capture the pawn.  Did Houdini really not see this coming? Stockfish demonstrating its superior endgame skills, now its lead is +7.
In game 68 Houdini's eval advantage got up to 1 but could not go higher. Houdini tried a knight sacrifice for pawns, exposing the black king to attack. It managed to get two rooks on the 7th rank and got the material back. Stockfish eval dropped to 0 and it countered with a rook on the 2nd file. The mutual attacks canceled out and the game ended in a drawn RB vs RN position.

Game 69 started with an eval advantage for Stockfish, when unexpectedly in move 14 Houdini saw an opportunity for a QN attack on the white king that resulted in a repetition draw on move 24. Shortest game of the match so far.
In game 70 Houdini held on to a small eval advantage and there was no early draw. From move 19 the engines agreed on a long series of moves which they then played out. The evals stayed in favor of Houdini, Stockfish gave a rook for a knight and pawns and only RBN vs BNN remained.

Stockfish's bishop was almost trapped and it took a few moves to get it out of the corner. The black knights had to move away from the white king to help defend the pawns, and they couldn't find a position where they also defend each other. After Stockfish exchanged its bishop for a knight and Houdini captured a pawn Stockfish had a long think, and then its eval started to jump. Houdini's eval followed a few moves later.  

The black a pawn was about to fall, the black g pawn was not a real threat and Houdini's remaining pawn could not be stopped without losing material, a won endgame for Houdini. Stockfish is back to +6.

No comments:

Post a Comment