After 70 games the score is tied 5-5 with 60 draws. Leela tied the score again though it had not been in the lead yet in the match. The last 30 games are going to be exciting. There was one game pair with a double white, the second one of the match.
Stockfish pushed pawns on the king side in game 61, Leela moved its knights there and Stockfish gave a rook and pawn to get rid of them. The white king was exposed and Leela moved its queen forward to attack. In a series of exchanges the engines reduced to a BB vs R position, Stockfish's eval went over 2. Leela moved its rook forward through the open king side, the engines traded pawns on the queen side and opened two files there. The center was blocked with the remaining 4 pawns for both engines, and Stockfish couldn't find an entry point for its pieces. Its eval only came down when the 50-move draw approached, the game was adjudicated on move 85. Did Stockfish miss a win here?
In game 62 Leela pushed pawns on the king side, Stockfish locked pawns there and did not attempt to attack. The engines opened the a file, all other files were locked by pawns except the f file. The engines exchanged a pair of rooks, then shuffled for a while with evals around 1. On move 27 Stockfish thought for 16 minutes before locking the f file as well, but its eval started to increase. The engines exchanged the remaining rooks and Stockfish's eval was over 3.
Leela arranged its pieces slowly and its eval also jumped, while Stockfish defended the open queen side and waited. On move 41 Leela gave a knight for two pawns in the center and created connected passers. It moved its knight to c6 to support the passers. When Stockfish exchanged knights Leela added a third connected passer on the c file. Leela captured a pawn on the king side, 4 passers were too many.
Stockfish lost a knight for one passer, then tried to delay with checks on the white king. When that didn't work Stockfish lost its queen and mate followed. Leela wins the game pair, the score is tied again at 4-4.
In game 63 all pieces remained on the board, the engines exchanged two pairs of pawns and opened the king side. Evals came down and the engines shuffled for a while, then in a series of exchanges the engines reduced to a BN vs R position. The pawn trades continued until there was only one pawn left for each engine, and the game was adjudicated. In game 64 the king side remained closed and the engines opened a file on the queen side. Queens were exchanged early, a series of exchanges led to a BB vs B position with Stockfish 4 pawns up and a passer on the 2nd rank. Leela had one pawn left, it could only shuffle but wouldn't lower its eval. The game was adjudicated on move 109.
Games 65-66 started with a 2-ply book 1. e4 b6, the Owen defense. In game 65 Stockfish's eval started at 1. The engines blocked the center, Stockfish had a space advantage and there were very few exchanges. The engines opened a file on the queen side and then mostly shuffled. Stockfish's eval increased to 1.5 and the engines exchanged another pair of pawns on the queen side. Stockfish tried to find a way to break through the queen side while Leela threatened the isolated pawn on b4. On move 54 Stockfish's eval was over 3 and its PV showed how it can clear the queen side and attack.
Leela decided to give a pawn and open the queen side on its own terms. Stockfish's eval jumped as it suddenly had two passers. In a series of exchanges Stockfish gave a bishop for two pawns, Leela captured one of the passers but the other reached the 7th rank. Leela lost material and stopped the passer, the game reached a queen ending with Stockfish a pawn up.
The white king was relatively protected while Stockfish had a passer on the h file facing the black king. After a while the queens were exchanged and the king and pawns ending was a win for Stockfish.
In game 66 the center remained open and the engines castled in opposite directions. Stockfish traded both its bishops for knights, this ruined the white pawn structure but gave Leela the bishop pair advantage. Evals increased as the engines exchanged pieces, they were around 3 after the queens were exchanged and the game reached a RBB vs RNN position.
The white bishops were strong in the open board. Leela created a passer on the c file and Stockfish created one on the h file. The bishops did not allow the black passer to advance, Stockfish gave a knight for two pawns to stop the white passer.
The engines exchanged rooks and the win was only a matter of time. Leela pushed a passer on the queen side and made sure the black passers on the king side could not promote. The game ended in a tablebase win just before Leela queened a pawn. There were two white wins in this opening, the score is still tied at 5-5.
In game 67 the engines locked the center and opened a file on the queen side. Both engines focused on the queen side, Stockfish doubled rooks and attacked the black a7 pawn, Leela had enough defenders. The engines shuffled for a while, then reduced to a RBB vs RBN position with equal material. Evals were low and wihtout pawn moves the game was quickly adjudicated. In game 68 the center was again blocked, this time the queen side remained closed. There were only a few minor piece exchanges after the start, the first pair of pawns was exchanged on move 17. After that the engines continued to exchange pieces until reaching a rook ending on move 29. Evals were low but there were still many pawns on the board. Both engines pushed passers forward, when they stopped moving the game was adjudicated.
Games 69-70 started with a 20-ply book in the Philidor defense exchange variation. The engines castled in opposite directions and the white queen moved forward in the center. In game 69 Stockfish pushed pawns on the king side and Leela pushed pawns on the queen side. There were no exchanges until move 22 when queens were exchanged. The engines continued to exchange pieces and pawns until the game reached a RBN vs RBN position. Stockfish was a pawn up but evals were low, the pawns didn't move and the game was adjudicated. Game 70 started similarly, the exchanges started earlier and the game reached a RRB vs RRB position on move 24. Stockfish gave a rook for a bishop and pawns, after exchanging a pair of rooks only R vs B remained and Stockfish was 3 pawns up. Evals were close to 0, Leela captured one black pawn before the game was adjudicated.
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