After 90 games Stockfish leads 27-8 with 55 draws. Stockfish adds another 2 game pair wins, it had a lead of +19 with 5 game pairs to play. KomodoDragon still hasn't won a game pair, in these 5 game pairs it hasn't won a game with white, something it managed to do at least once in each 5 game pair group in games 1-80.
Games 81-82 started with a 20-ply book in the Nimzo-Indian Rubinstein variation, played by GM Sadler (the second time I've seen this in this match). White started with a pawn majority on the queen side. In both games the engines castled short after the start. In game 81 a pawn exchange on the queen side created a passer for KomodoDragon. After some preparations there was a series of exchanges that left a QB vs QB position, KomodoDragon was up a pawn with two passers. However after exchanging queens the game reached an opposite color bishop ending, evals came down and the game was adjudicated. In game 82 the pawn exchange on the queen side created passers for both engines. Stockfish captured a pawn with its queen on the king side, then KomodoDragon gave another pawn and exchanged queens. In a series of exchanges KomodoDragon got one of the pawns back and the game reached a RN vs RB position. KomodoDragon wouldn't lower its eval for the draw rule, the engines shuffled for a long time. The game was adjudicated after the rooks were exchanged.
Games 83-84 started with an 18-ply book in the King's Indian, normal variation, with a locked center and without exchanges. In game 83 KomodoDragon castled long, the engines pushed pawns and locked the king side, and then they locked the queen side as well. On move 25 there was only one possible pawn move left, the board was totally blocked. Stockfish's eval came down, KomodoDragon was still hopeful. The last pawn move and a bishop exchange extended the shuffle to move 105, the game was adjudicated close to a 50-move draw.
In game 84 Stockfish castled long as well, the engines locked the g and h files but a pawn exchange kept the f file partially open. There was a minor piece exchange on the queen side and the black a pawn became isolated. There was a period of shuffling with evals around 2, then evals increased while Stockfish moved a knight b5-c3-e2-g3, preparing for an attack on the king side.
KomodoDragon had to give a knight to capture the passer, Stockfish was a rook up for pawns and it saw mate in its PV. Stockfish moved a rook forward, the black pawns had no defense. Stockfish created a passer and won. Stockfish wins the game pair, it leads 26-8.
Games 85-86 started with a 14-ply book in the French Winawer advance, poisoned pawn variation, played at the highest level of human chess. Both games diverged quickly from theory. In game 85 after a few early exchanges the engines played out a long PV agreement and reduced to a QRR vs QRR position on move 26. Evals came down to 0, captures and pawn moves kept the game going for 40 more moves. In game 86 the queens were off early, KomodoDragon pushed pawns on the king side and evals came slowly down. There were many pawn exchanges, the engines exchanged a pair of rooks through an open file on the queen side, then reduced to a drawn N vs B ending.
In game 87 KomodoDragon was ahead on development after the start, evals were over 1 but did not increase. Stockfish pushed a pawn on the queen side and opened a file, for several moves it offered a knight and KomodoDragon didn't accept - there was either a pin or another a more dangerous threat to deal with first. After the knight moved the engines opened the center, then gradually exchanged pieces until the game reached a rook ending. KomodoDragon was a pawn up but only enough for a draw. In game 88 KomodoDragon did not develop any piece on the queen side after the start. For a few moves it seemed Stockfish's eval may start to increase but it stayed mostly under 1.5. The engines exchanged minor pieces, then the queens were off. KomodoDragon's pawn structure was weak but evals went below 1 and it stabilized its position. The engines again reduced to a drawn rook ending
In game 89 the engines opened the center, evals stayed around 1 until the engines exchanged most minor pieces. By move 27 only QRR vs QRR were left, both engines had a passer in the center. There were a few pawn trades and evals came down until the game was adjudicated.
In game 90 there were no pawn exchanges after the start and the center stayed closed. A minor piece exchange resulted in a white passer in the center. KomodoDragon pushed pawns on the king side, it formed a long line across the board that looked impossible to penetrate. The engines shuffled, on move 44 the last knights were exchanged, no piece could jump across the line. The shuffle continued and the engines went into blitz mode. Stockfish's eval started to increase as it contemplated what would happen if it sacrificed its bishop to break the wall.
KomodoDragon could capture pawns but it had to stop the passer first. With checks KomodoDragon managed to capture the passer on d6, Stockfish responded by capturing the black a pawn. It was a long endgame but there was no doubt Stockfish would covert. Eventually Stockfish queened a pawn and won with two queens against one. Stockfish wins the game pair, it leads 27-8.
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