After 90 games Stockfish leads 24-19 with 47 draws. Leela won another game pair and Stockfish's lead is down to 5 wins. There were 4 drawn game pairs, in one of these there were two white wins. Stockfish hasn't won a game pair in the last 13 played, while Leela won 3. There are only 5 game pairs to go so Stockfish is the favorite to win the match, but Leela is still fighting.
Games 81-82 started with a 22-ply rare sideline in the KID, Petrosian variation. All pieces and pawns were on the board and the center was blocked. In game 81 the engines pushed pawns across the board, Stockfish gave a pawn and opened a hole in the pawn line on the king side. Stockfish placed a knight on f5 and Leela moved its king to the corner. Evals came down and there was a long series of exchanges that opened the center and queen side. The result was that Stockfish was down a knight for a pawn with connected passers on the king side. After some shuffling Stockfish gave a rook and a bishop and queened a passer. The game ended in check repetition. In game 82 the engines opened the f file and the a file, then exchanged a pair of rooks. Evals came down, after exchanging a pair of bishops the engines started to shuffle. On move 40 Leela pushed the g pawn forward until Stockfish captured it. The engines reduced to a QB vs QN position, evals were low and the game was adjudicated.
Games 83-84 started with a rare sideline in the KID Fianchetto variation. In game 83 the engines blocked the center, Stockfish opened the queen side and Leela pushed pawns on the king side. The white king walked to the king side without castling. Stockfish had two strong knights in the center, it placed its major pieces on half open files on both sides. However evals slowly increased. Leela pushed a pawn to h6, then captured a pawn and created a passer on the queen side.
Leela exchanged a pair of knights, its passer shifted to the b file. With rook support Leela pushed the passer to the 5th rank where it was blocked. Stockfish doubled rooks on the f file, attacking the f3 pawn and trying to prevent it from moving forward. Leela captured one rook for a bishop, then threatened the back rank from the open c file. Stockfish blocked the c file and opened the way for the white passer to advance. Stockfish was desperate, it gave the second rook for a bishop to block the f pawn.
Stockfish quickly lost more material, Leela queened and mated.
In game 84 the engines blocked the center but there were no pawn exchanges after the start, only a few minor piece exchanges. Stockfish walked its king to the queen side, all files were blocked except the b and f files and the engines started to shuffle. Leela's eval dropped to 0, Stockfish couldn't find any safe way to move past the pawn lines. Pawn moves and captures reset the 50-move counter on moves 36, 83, 128, 175 (Stockfish gave a pawn), 204, 252 (Leela gave a pawn), 301 (knight exchange), 310 (Stockfish gave a pawn), and 329. The game finally ended on move 379 in a 50-move draw, after approximately 350 moves of nothing. This is a new TCEC record for most moves in a game. Leela wins the game pair, Stockfish leads 23-18.
Games 85-86 started with one of the main lines in the Czech Benoni defense, the center was blocked and all pieces and pawns were on the board. In game 85 there was one pawn exchange on the king side and Leela's eval started to increase. Stockfish captured a pawn, the engines played a long PV agreement and Leela's eval slowly came down. Stockfish gave back the pawn and Leela went a pawn up, then in a series of exchanges the engines reduced to a same color bishop ending. Leela wouldn't lower its eval for a long time, the engines shuffled and exchanged a few pawns. The game was adjudicated on move 118. In game 86 there were no exchanges after the start, the engines exchanged a pair of knights and mostly shuffled behind their pawn lines. On move 43 the engines exchanged a pair of bishops, then Stockfish captured a pawn but there was a stable pawn wall across the board. The engines shuffled for a long time, the 50-move counter was reset on moves 98 (knight for rook trade), 143, 182 (Stockfish gave a pawn), 224 (Stockfish gave another pawn), 233, 247 (queen exchange). On move 297 the game finally ended in a 50-move draw. Another long game with nothing happening.
Games 87-88 started with a rare sideline of the English symmetrical variation. In game 87 Stockfish exchanged minor pieces and its queen moved forward on the queen side. Stockfish captured two pawns and created 3 connected passers. Leela captured one passer and pushed its center pawns, Stockfish gave a rook for a bishop to protect its king. Stockfish pushed its passers forward, after exchanging queens the game reached a RB vs BN position on move 38.
Stockfish gave up the d and h pawns quickly, but it protected the others and Leela had a hard time trying to improve. The engines shuffled and evals drifted down. On move 65 Leela exchanged a pair of pawns on the king side, Stockfish's eval jumped.
The game was far from over but evals started to increase. Leela slowly moved its king to the center. The black king moved to the queen side and on move 85 Leela captured the black e pawn. The white f pawns became doubled passers, Leela slowly pushed them forward. Eventually Leela queened and the game ended in a tablebase win on move 121.
In game 88 the engines repeated game 87 for 20 plies, Leela captured one pawn on the queen side but Stockfish protected the second one. Stockfish regained the pawn and exchanged a pair of rooks, its eval started to increase. Leela captured the second pawn on the queen side and created two passers there but Stockfish captured one of them. After exchanging queens Stockfish gave a rook for two minors and reduced to a BB vs R ending.
Stockfish exchanged a pair of pawns on the king side and created a 3 vs 1 pawn majority in the center. Its eval showed a clear win while Leela's eval increased very slowly. Leela pushed its passer and eventually captured a bishop for it. Stockfish slowly pushed the pawns forward, making sure the black rook couldn't stop them. It finally queened a passer on move 81, mating a few moves later. There were two white wins in this game pair, Stockfish leads 24-19.
Games 89-90 started with a 24-ply rare sideline in the Benoni classical variation, Czerniak defense. In game 89 after one move the engines started to play out a very long PV agreement. Stockfish gave a bishop and opened files on the king side. There was a threat to the white king, Leela gave back the piece and reduced to a RN vs RB position with white a pawn up. Stockfish's eval dropped, the engines traded pawns and then the rooks were exchanged. Leela wouldn't lower its eval for a long time, the game was adjudicated on move 92. Game 90 started with a 30-ply repeat of game 89. The game reached the same RN vs RB position, the engines traded pawns and Leela lowered its eval for an early adjudication on move 49.
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