Season 22 superfinal games 21-30

After 30 games Stockfish leads 12-3 with 15 draws. Stockfish continues to be dominant in the superfinal, it won 3 more game pairs. For the third time KomodoDragon managed to win a game and immediately Stockfish won the reverse. Can KomodoDragon win a game pair in this match?

In game 21 the engines locked the center, a pair of knights was exchanged early but there were no exchanges after that for a while. Evals were under 1 and drifted down, there was one pawn exchange and then Stockfish captured a free pawn. This led to a series of exchanges and a quick drop of the evals, KomodoDragon was up a rook for a knight and pawn but with no advantage according to both engines. The game ended in a tablebase draw 15 moves later.

In game 22 the engines opened the center and exchanged queens early. The engines mainly played behind the pawn lines, the king side was locked. After a while the engines opened the queen side, engines remained around 1. After trading a pair of rooks on move 42 Stockfish's eval started to increase, while KomodoDragon did not see danger. Stockfish didn't seem to be doing anything for a while, until it forced more exchanges and reduced to a BN vs BN position on move 60. By then KomodoDragon's eval jumped as well.

KomodoDragon had 3 weak pawns to defend, the black bishop had no white pawn targets. Stockfish also threatened to move its king forward, KomodoDragon couldn't defend against all the threats. Eventually Stockfish captured the black e pawn, queened a passer and won. Stockfish wins the game pair, it leads 9-2.

Games 23-24 started with a 6-ply book in the Pirc Czech defense. In game 23 the engines continued the main line for a while before diverging. For a while evals increased, KomodoDragon exposed the black king with a knight sacrifice. Then the engines played a long PV agreement where Stockfish gave the material back, KomodoDragon was up a pawn but evals came down a little. In a series of exchanges the engines reduced to a QN vs QB position and the game was adjudicated.

In game 24 KomodoDragon diverged from the main line very quickly and soon regretted that. Evals increased quickly and Stockfish went a pawn up with an advanced passer on the queen side. At the end of a PV agreement both evals were over 2 already on move 16.

Evals continued to increase as Stockfish shuffled for a while. KomodoDragon tried to counter on the king side after both engines castled, Stockfish exchanged a pair of rooks through an open file and this was the end of black's attempt. The Stockfish captured a second pawn on the queen side.

Stockfish now had 3 connected passers on the queen side, after exchanging queens it was only a matter of time until the pawns advanced and KomodoDragon started to lose material. Stockfish queened twice and mated. Stockfish wins the game pair, it leads 10-2.

Games 25-26 started with a 16-ply book in the Scandinavian defense, one of the main lines. In both games the engines played less popular moves and diverged from theory quickly. In game 25 there was one pair of knights exchanged after the start, Stockfish didn't castle its king and both engines played behind their pawn lines. After a few pawn exchanges the engines started to shuffle, KomodoDragon couldn't find a way to attack and evals slowly came down. KomodoDragon avoided the 50-move draw but the game was adjudicated shortly afterwards. In game 26 the engines exchanged a pair of pawns on the king side, KomodoDragon did not castle its king as in the previous game. The engines played out long PV agreements, the evals came down and the game reached a RBB vs RBN position. Stockfish was a pawn up but that was not enough to win. After exchanging rooks evals slowly decreased and the game was adjudicated.

Games 27-28 started with black a pawn up in the Dutch Korchnoi attack. In game 27 the engines played a long PV agreement almost immediately after book, there were many exchanges and on move 18 only QRN vs QRN remained. KomodoDragon was a pawn up  with a doubled passer in the center.

Evals increased despite many king moves by the white king, the engines exchanged queens and Stockfish pushed pawns on both sides of the board. KomodoDragon waited for an opportunity, on move 42 its rook moved to the back rank where it could target the black pawns. 

KomodoDragon was patient and before long it was 3 pawns up. It then reduced to a winning king and pawns ending.

In game 28 KomodoDragon gave the pawn back and developed its queen side pieces. Again the engines had a long PV agreement, both engines castled long and there were pawn and minor piece exchanges. Stockfish went a pawn up, it had an advanced passer in the center but traded it for a black king side pawn. By move 27 only QRR vs QRR remained.

KomodoDragon had a passer but couldn't turn it into a dangerous threat. After exchanging a pair of rooks Stockfish captured the black f pawn and created connected passers. Eventually Stockfish traded one passer for the black h pawn, then reduced to a winning rook ending. The game ended 30 moves later just before mate on the board. There were two white wins in this opening, Stockfish leads 11-3. 

In game 29 there were no exchanges after the start, the engines seemed to avoid contact and there were very few pawn moves. Evals slowly drifted down, the first exchange was of bishops on move 23. KomodoDragon moved both knights forward on the king side and Stockfish exchanged a pair of knights. On move 39 the engines exchanged their first pawns, then reduced to a QRN vs QRB position. Evals came down to 0, the game was adjudicated much later in a rook ending.

In game 30 again there were no exchanges after the start, this time all the pieces stayed on the board. Evals were around 1 and didn't change a lot until move 30, KomodoDragon seemed to be doing OK as black.

Stockfish thought the black move 30 was a  mistake and its eval jumped. It was interesting that there was a 24-ply PV agreement at this stage, KomodoDragon predicted the same continuation that Stockfish did. Indeed the engines played this sequence of moves, including a rook for bishop exchange. On move 47 the game reached a QRB vs QBB position.

Evals were still not very high and the material difference was small, all pawns were on the king side with no passers or pawn majority. However, Stockfish found a way as it usually does, perhaps KomodoDragon made mistakes in time trouble. After exchanging queens evals increased quickly, eventually Stockfish captured a pawn and then a bishop. The game ended in a tablebase win. Stockfish wins the game pair, it leads 12-3.