Season 21 superfinal games 11-20

After 20 games Stockfish leads 3-1 with 16 draws. No change in the score after 10 straight draws.

In game 11 Leela castled long, Stockfish moved its king and castled short by walking. There were many early exchanges that opened the position and only QRN vs QRN remained on move 25. Evals were low and the engines only shuffled, the game was adjudicated by the draw rule. Game 12 started similarly, though there were less exchanges. Stockfish opened the king side and tried to attack the black king. Leela exchanged pieces and only RRN vs RRN were left on move 32, the black king was exposed but not in danger. Stockfish exchanged a pair of rooks and went a pawn up, after the pawns stopped moving the engines started to shuffle. A few exchanges led to a RN vs R ending with black a pawn up, the game was finally adjudicated on move 147.

In game 13 there were a few early exchanges and the engines opened a file in the center. Evals came down close to 0, the engines exchanged all rooks and the game reached a QB vs QN position on move 27. The game was adjudicated in a queen ending with both queens giving check in turn. In game 14 there were less exchanges, Stockfish pushed pawns in the center and managed to get a passer to d6. Leela blocked the passer and evals came down, a series of exchanges reduced to a RRB vs RRB position. Leela captured the passer and the game reached a drawn rook ending.

In game 15 Leela castled long, a series of exchanges opened the center. Evals came down as the engines exchanged pieces and Stockfish castled short. Leela opened the king side, the black king hid behind a white pawn and evals were close to 0. The engines continued to exchange and move pawns, the game ended in a tablebase draw. Game 16 started similarly, this time queens were exchanged early as well and both engines castled long. Evals came down and the exchanges continued, the game reached a RB vs RB position on move 33. Stockfish was a pawn up and it wouldn't lower its eval, the engines shuffled and the game was finally adjudicated on move 88.

Games 17-18 started in the St. George defense with white a pawn up and with a passer on the queen side. In game 17 Stockfish's eval was around 1 from the start. On move 8 the engines started to play out long PV agreements until move 20, queens were exchanged, Stockfish castled while Leela kept its king in the center. Evals came down, Leela's passer did not advance, pawn moves and exchanges kept the game going. The game was adjudicated in a RN vs RN position. In game 18 Stockfish gave back the pawn, both engines castled short and Stockfish pushed the passer forward. Stockfish's eval stayed around 1 while the engines mostly shuffled, the white passer reached the 6th rank but couldn't advance further. Leela went a pawn up, Stockfish's eval drifted down in a long shuffle, on move 85 the exchanges began. The engines reduced to a RRN vs RRB position, the white passer advanced to a7 where it was blocked. The game was adjudicated once the exchanges stopped.

In game 19 the black king was forced to move without castling. Leela attacked with a queen and knight and captured a rook for a bishop, however evals were low. The engines exchanged pieces and on move 28 only QR vs QN remained with black two pawns up. Stockfish had connected passers on the king side that Leela had to watch, for a while there was no progress and then the exchanges began. The game was adjudicated in a drawn R vs N position. In game 20 there were long PV agreements after the start. In the first PV agreement the engines opened the king side, and in the second both engines castled long while evals came down. After a series of exchanges only QNN vs QNN remained on move 29. Stockfish moved its pieces forward to attack, while Leela created an advanced passer in the center. The engines reduced to a knight ending, Stockfish captured the passer and was a pawn up but it was not enough. The pawns stopped moving and the game was adjudicated.