Season 22 superfinal games 51-60

 After 60 games Stockfish leads 19-6 with 35 draws. KomodoDragon still hasn't won a game pair, it won its 6th game and Stockfish won the reverse again. Stockfish only won 1 game pair out of the last 5, it has a +13 lead with 20 game pairs to go. The highest win margin for a TCEC superfinal with 100 games is +20, this record may be broken this season. 

Games 51-52 started with a 20-ply book in the Dutch Leningrad variation. In game 51 the engines left theory quickly, Stockfish pushed pawns in the center and managed to get a pawn to f2 through an exchange. In a long series of exchanges the engines reduced to a QRB vs QRB position with white a pawn up. After some shuffling the queens were exchanged, evals came down and the game was adjudicated. In game 52 again the engines left theory but in a different line, again Stockfish was a pawn up. Stockfish pushed a passer in the center to the 6th rank, a second passer was blocked by the black queen. Evals came down and the game was adjudicated still with many pieces on the board. 

Games 53-54 started with a 12-ply book in a KID normal variation, which was played in one of GM Sadler's games (coinicidence?). In game 53 there were a few pawn exchanges after the start, all pieces stayed on the board. KomodoDragon pushed a pawn to h6, forcing a black bishop to the corner. The first piece exchange was on move 26 when the engines exchanged bishops. Stockfish managed to get its bishop out of the corner, it was later exchanged for a knight. Evals came down, the engines exchanged pieces until reaching a drawn rook endgame. In game 54 again there were a few pawn exchanges after the start. Stockfish pushed the h pawn but exchanged it rather than move it to h6. There was one B for N trade and evals came down. In a series of exchanges the engines reduced to a QR vs QB position, KomodoDragon ended the game in a perpetual check.

Games 55-56 started with a 2-ply book, 1 d5 b5, the Polish defense. In game 55 both engines did not castle their kings. KomodoDragon let its king side rook out through the h file and the white king walked to safety. Stockfish moved its king to the 7th rank to clear a path for its king side rook. There were a few pawn and minor piece exchanges, Stockfish blocked the queen side with its knights but it had two weak pawns there. Evals increased slowly, the engines exchanged queens and Stockfish tried to block across the board.

For a while the engines shuffled while KomodoDragon decided where to attack. On move 43 KomodoDragon started to attack on the queen side, it reduced to a RN vs RN position a pawn up. Pawn trades opened the board, both engines had passers and KomodoDragon had a pawn majority and connected pawns on the queen side.

KomodoDragon captured the black a pawn to create connected passers. It gave away its f passer and then gave the rook for a knight. Stockfish could not stop the two passers advancing with its rook alone, the game ended in a tablebase win.

In game 56 Stockfish castled its king, then made the black king move through an exchange. KomodoDragon moved its king to h7 so its king side rook could get out of the corner. In a long PV agreement KomodoDragon gave two pawns to open the board and activate its pieces. The engines continued to exchange pieces until only RB vs RB were left.

Stockfish had to be careful not to get into an opposite color bishops ending, so it was cautious and patient. After exchanging a pair of pawns on the king side Stockfish found an opportunity to push the e pawn forward to the 7th rank. KomodoDragon guarded the queening square, but also had to protect its other pawns. KomodoDragon refused to give away its a pawn, in the end Stockfish traded its passer for the black g pawn. 

It was still very hard for Stockfish to push the g pawn forward safely. It used the threat of a rook exchange that would create an advanced passer on the queen side to drive the black rook away. On move 70 the white g pawn advanced, and 10 moves later KomodoDragon was forced to give its bishop for the passer. The last black pawn was captured and the game ended in a tablebase win. There were two white wins in this opening, Stockfish leads 18-6.

Games 57-58 started with an 18-ply book in the Ruy Lopez anti Marshall variation. In game 57 KomodoDragon went up  a pawn early and evals came down quickly. After move 20 the engines exchanged pieces and the game reached a RB vs RB position. KomodoDragon wouldn't lower its eval for the draw rule, this delayed adjudication by 30 moves. In game 58 Stockfish went a pawn up in a different line. KomodoDragon regained the pawn, evals came down as the engines exchanged pieces. The game reached a QR vs QR position and Stockfish went a pawn up again. Here adjudication was delayed for 40 moves because of exchanges and pawn moves. 

Games 59-60 started with a 16-ply book in the KID orthodox variation, a line played many times in high level human games. In game 59 the engines left theory quickly, the center was blocked and there was one pair of pawns exchanged that opened a file on the queen side. The engines mostly shuffled, a pair of bishops were exchanged on move 25, a pair of rooks on move 35. On move 57 the remaining bishops were exchanged and there was a long shuffle, 30 moves later the engines exchanged pawns, evals came down and the game was adjudicated.

In  game 60 the engines left theory as well. KomodoDragon surprised Stockfish with its 11th move, and Stockfish's eval jumped after black's 12th move. KomodoDragon predicted the moves correctly in its 11th move PV, but Stockfish considered the line a mistake. The center opened, the white queen came forward and Stockfish captured two pawns. After exchanging queens the engines traded NN for R, the game reached a RR vs RNN position on move 28. KomodoDragon's eval also increased, too late to change its choice.

The engines were still in PV agreement. Stockfish had a passer but was down a piece and it was difficult to support the passer. KomodoDragon captured the b pawn, Stockfish pushed the e pawn forward. This was also a danger to the black king, eventually KomodoDragon captured the e pawn while Stockfish captured the black a pawn. 

The flank passer was a greater challenge for the black knights, while KomodoDragon was busy watching the passer Stockfish cleared the black pawns on the king side and created connected passers there. Stockfish used a timely rook for knight sacrifice to queen a pawn and win. Stockfish wins the game pair, it leads 19-6.