After 60 games Stockfish leads 4-3 with 53 draws. Leela won its first game pair of the match, then won a second game pair and tied the score. Stockfish then regained the lead with a game pair win of its own. The opening bias increases and there were 3 decisive games in the last 10. There are 40 games left, Leela has shown in the last 10 games that anything can happen.
In game 51 the center was locked, Stockfish pushed pawns on the king side but Leela kept its king with sufficient pawn support. Stockfish castled long after a while, after exchanging queens Stockfish moved its king forward to prevent the black rook development on the a file. The engines shuffled for a while, then reduced to a RRB vs RRB position and evals came down. After trading a few pawns the game was adjudicated.
In game 52 Leela pushed pawns on the king side, it didn't castle its king though but moved it to f1 instead. Leela didn't trade pawns on the king side, it pushed a pawn to h6 and trapped a black bishop in the corner. On move 17 there was a long PV agreement, Stockfish gave a knight for pawns and opened the queen side. Stockfish stopped to think long, the PV continued to play out but Stockfish's eval jumped over 2, it wasn't happy about the outcome. The engines exchanged most pieces, Stockfish was 4 pawns up for the knight. On the other hand Leela's pieces were better placed and the black king was vulnerable.
Leela captured two pawns quickly, the white c pawn became a dangerous passer. Stockfish tried to counter by pushing two pawns in the center, however Leela took over the 7th rank and Stockfish had to protect its king. Leela gave its rook for a bishop and pushed the passer to the 6th rank.
Leela had enough resources to protect its passer and keep an eye on the advancing black pawns. Stockfish couldn't prevent a queening, Leela won material and mate followed. Leela wins its first game pair, Stockfish leads 3-2.
Games 53-54 started with a 27-ply book in the Semi-Slav defense, Meran variation, where both engines queened early and had two queens. In game 53 the engines exchanged a pair of queens, then Stockfish went a pawn up and exchanged the remaining queens. The engines reduced to a drawn rook ending with white a pawn up. Stockfish's eval was too high for the draw rule and the game continued until move 81. in game 54 Stockfish went a pawn up before the exchanges started, all queens were exchanged and the game reached a RB vs BN position with black two pawns up. Evals were close to 0, both engines pushed passers forward. Leela gave a bishop to stop a black passer, the game was adjudicated before Stockfish had to lose a bishop for a white passer.
There were no exchanges after the start in game 55, except for a pair of pawns. The engines developed their pieces and evals came down. On move 20 the engines started to exchange pieces and Leela went a pawn up. On move 41 only BN vs BN remained with Stockfish a pawn up and evals close to 0. The engines exchanged knights and were left with an opposite color bishop ending, but then Stockfish raised its eval and wouldn't lower it. The game was adjudicated only on move 180.
In game 56 Stockfish went a pawn up and traded one of its bishops for a knight. The engines exchanged queens and Leela placed a protected knight on c6. After a while Stockfish gave its second bishop to get rid of the white knight, giving Leela the bishop pair advantage. The white bishops were strong in the open center and evals started to increase. Stockfish gave a rook for one of the bishops and a second pawn, leading to a RRB vs RNN position.
Leela moved a rook to the 7th rank, Stockfish tried to counter with a passer on the queen side. Leela traded its bishop for a knight and stopped the black passer on the 2nd rank. Evals were around 3 in a RR vs RN position.
Stockfish couldn't protect the doubled pawns on the queen side and Leela captured them after a while. The white rooks started to threaten Stockfish's king and it exchanged a pair of rooks.
The remaining pawns were all on the king side. Stockfish may have hoped for a fortress but not at this level. The white king came forward and Leela drove the black knight away with its rook. The game ended in a tablebase win. Leela wins the game pair and ties the score 3-3.
Games 57-58 started with a 20-ply book in the QGD Chigorin defense, white with a bishop pair, black with two knights, and a gap in the white king side pawns. In game 57 Stockfish gave a pawn early to keep the center files closed. Leela moved its queen forward on the queen side, it captured a pawn and created a potential passer. Stockfish castled late, the engines exchanged queens and evals were close to 0. There were no pawn moves or captures and draw rule ended the game with rooks and minors on the board. Game 58 started similarly, Leela gave a pawn, Stockfish had a passer on the queen side and the engines exchanged queens. Leela didn't castle, it created a passer in the center and pushed it to the 7th rank. Stockfish pushed its passer forward and gave a rook for a bishop to block the white passer. Leela gave a rook for a knight and in the resulting rook ending both passers were captured. The game ended in a tablebase draw.
In game 59 Stockfish's eval was around 1 from the start. Leela opened the queen side and Stockfish went a pawn up. Leela tried to open a file on the king side, Stockfish refused and gave a pawn instead. It created a passer in the center, then after thinking for 19 minutes Stockfish's eval had a small jump though it played the expected move. Leela went a pawn up and thought it was safe, Stockfish's eval increased over 3.
The engines exchanged a pair of knights, Stockfish surprised Leela by playing b4 and offering a rook for a bishop. Leela thought long before accepting, it started to feel nervous and its eval jumped over 1. Stockfish predicted the sequence of moves played, the engines exchanged queens and Stockfish forked the black rooks with its bishop. This led to a RN vs RN position, Leela was still up a pawn and Stockfish with a passer on the 7th rank.
All pieces focused on the white passer, Leela couldn't move its king closer safely. After a while the engines exchanged rooks, then Leela lost its knight to capture the passer.
The endgame was slow but straightforward for Stockfish. Leela couldn't protect its pawns, the game ended in a tablebase win.
In game 60 the black queen tried to be active on the king side. Leela pushed pawns there, Stockfish moved a knight all the way from the other side of the board and sacrificed it for 3 pawns. After a few exchanges the black pawns stabilized and the engines shuffled for 20 moves. Evals came down and the engines reduced to a QN vs Q position, black 3 pawns up. Both kings were exposed to checks, when Leela created a passer Stockfish gave checks with its queen and the game was adjudicated. Stockfish wins the game pair and leads 4-3.
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