Saturday, March 31, 2018

Season 11 superfinal, games 1-10

This season's superfinal is between Stockfish and Houdini.

After 10 games Stockfish leads 2-0 with 8 draws. 

In game 1 Stockfish had a pawn advantage from the opening, evals increasing over 1. After a few exchanges the evals dropped to 0 and Houdini regained the pawn. The engines traded down to a RB vs RN position and then a 6-man draw. In game 2 the evals stayed under 0.6. Stockfish gave a second pawn for a king side attack, then sacrificed a bishop to get a repetition draw in a line the engines saw 10 moves in advance.

After a few early exchanges in game 3 Stockfish's eval started to increase. Evals were over 1 when Stockfish gave a pawn and opened the king side, after exchanging queens there was no immediate threat to Houdini's king in a RRB vs RRB position. Stockfish got the pawn back but only got a drawn bishop ending. Game 4 reached a drawn rook ending on move 26, evals close to 0 from the start.

Game 5 started with an unusual Q vs BB and pawns imbalance. Evals were over 1, with such a biased opening the question was: can black hold the position?

Houdini tried to break through the center. Stockfish gave another pawn and its king was totally exposed facing a pair of black passers. On the other hand the passers formed a screen preventing black rook attacks on the white king. Houdini also had to keep an eye on the white passer on the 7th rank.

After the advanced passers were eliminated Stockfish gave the queen back and traded down to a RR vs RB position. Evals indicated a win for white.

The black king was trapped in the corner and the white king was very active in the center. Stockfish started to capture pawns and the game was adjudicated quickly. First win in the superfinal, but could Houdini win playing white?
In game 6 Houdini took the time to castle on the queen side and to find a safe spot for its king. The engines were essentially shuffling from move 20, Houdini had an eval advantage close to 1 but evals did not move for a long time. More than 40 moves later Houdini opened up the position and evals turned slightly in Stockfish's favor. Houdini found a spectacular draw, sacificing all its pieces for a stalemate.

After a few early exchanges in game 7 the engines created long pawn lines across the board, with only a few possible break points. Stockfish had a knight which could be better than Houdini's bishop in such positions.

The engines shuffled for 25 moves and then Stockfish crashed through the king side, sacrificing the knight and clearing the king side pawns. Stockfish's eval jumped over 2, Houdini's eval stayed below 1, which engine was right?

Stockfish used the black exposed king, backrank pins and threats on the queen to win a pawn on the queen side. Houdini's eval slowly increased as it saw the danger. At the right moment Stockfish exchanged queens.

Stockfish gained another pawn and its 4 passers, two connected pairs, were strong enough for a win. Two wins in a row for Stockfish playing white, this time the opening was not so biased like game 5.
In game 8 Houdini pushed pawns on the king side and it kept its king uncastled, away from the queen side where Stockfish pushed its pawns. Stockfish had a bishop pair and was a pawn up, its eval around 1, Houdini countered with better rooks and threats on the black king. Stockfish gave a rook for a knight, and after exchanging queens evals came down in a RR vs RB position. Houdini had to watch out for a black passer advancing, resulting in a draw.

Game 9 started with Houdini a pawn up and with an eval advantage. Both kings remained in the center, Houdini gave the pawn back and after queen exchange the evals dropped to 0. The game reached a drawn double rook ending. In game 10 both kings castled, Stockfish kept the pawn advantage and the pawn lines became static after move 22. Stockfish avoided a 50-move draw but the game drawn with a 3-fold repetition.

No comments:

Post a Comment