Season 16 superfinal games 11-20

After 20 games Stockfish leads 3-1 with 16 draws. AllieStein's losses came from two blunders, where it realized its mistake almost immediately. It needs to improve its analysis to avoid these mistakes.


AllieStein had an eval over 1 at the start of game 11. There were very few exchanges, the engines played behind their pawn lines and AllieStein had a space advantage. Stockfish gave a pawn and opened a file on the queen side, evals came down and after a series of exchanges only QN vs QB remained. The queens were exchanged and the engines continued to play 40 more moves before adjudication.

In game 12 there were again almost no exchanges after the start. Evals started below 1 and were more or less stable. AllieStein pushed pawns on the king side, this added space for its pieces while weakening its king. A pawn exchange opened the king side, evals were low.

Stockfish's eval jumped over 2 and AllieStein's eval jumped a move later. The black queen became trapped in front of the pawns and Stockfish traded a rook and a bishop for it. The advancing black pawns looked dangerous but evals were over 5.

AllieStein continued to fight, it pushed one pawn all the way to promotion and gained some material for it. However it was only temporary, Stockfish reduced to a QN vs RBN position with 3 queen side passers and the game was adjudicated.

In game 13 Stockfish walked with its king to the king side without castling. The center was blocked, AllieStein kept its king uncastled, its eval increased over 2 and Stockfish's eval went over 1. The queen side opened, AllieStein pushed pawns on the king side. Stockfish placed its pieces in a defensive structure, after a few exchanges only QBB vs QBN remained and the engines started to shuffle. AllieStein couldn't break the fortress, the game ended on move 137 in a 50-move draw.

In game 14 AllieStein let Stockfish capture two pawns on the king side while it captured two pawns on the queen side. Stockfish eventually castled its king, away from most black pieces. AllieStein kept its king exposed in the center, evals came slowly down.

Stockfish opened files in the center and on the king side, evals came down to 0. All the major pieces were active and the kings were exposed, there was always the possibility of a perpetual check draw. AllieStein was sure Stockfish was about to capture the c3 pawn, it thought 2 seconds and missed Stockfish's reaction with eval over 5.

Analysis shows that if AllieStein takes the bishop on c5 with its pawn it loses the e4 rook and the game reaches a RR vs RN losing endgame. Taking with the queen is mate in 3, running with the king leads to losing the queen and a quick mate. AllieStein chose to block the check with its knight, and after a few exchanges the game was adjudicated as Stockfish was about to capture a rook. A huge blunder by AllieStein.

Both kings remained uncastled in game 15. AllieStein pushed pawns on the king side, it gave two pawns and opened the king side leaving its king exposed. After many exchanges only QBN vs QBB remained, AllieStein got one pawn back and attacked the black king. Stockfish sacrificed a bishop and starting giving checks. There were a few more exchanges but in the end AllieStein couldn't escape the checks and the game was adjudicated on move 104. In game 16 Stockfish pushed pawns on the king side and kept its king uncastled, while AllieStein castled its king. The engines gradually exchanged pieces ane evals were low, Stockfish went a pawn up and created a queen side passer. For a short while evals jumped over 2 but it was a false alarm. AllieStein threatened the exposed white king using the back ranks, the engines reduced to QN vs QB position and Stockfish gave checks until adjudication.

In game 17 there were almost no exchanges after the start. Then in a long series of exchanges almost all the pieces were removed and RNN vs RBN remained on move 30. Stockfish had a queen side passer, it pushed it to the 2nd rank but there AllieStein captured it. The engines exchanged a pair of knights and started to shuffle. Eventually the rooks were exchanged and the game ended in a tablebase draw. Stockfish started game 18 with an eval around 1 that slowly increased. Again there were no exchanges after the start and then a long series of exchanges, by move 33 queens were off and most queen side pawns as well. Evals were over 2 and still increasing. Stockfish managed to capture a bishop for pawns and the game reached a RB vs R position. Stockfish's eval was over 3 yet AllieStein found a fortress that Stockfish couldn't break. The white king stayed in the corner and the white pieces were not strong enough to capture a pawn or attack the black king. The game ended in a 50-move draw.

Game 19 was a miniature that ended in a repetition draw on move 16 after less than 30 minutes. In game 20 there were no exchanges after the start, on move 27 Stockfish opened a file in the center and then captured a rook for a bishop. Evals stayed below 1, AllieStein blocked the open file and the pawns stabilized. On move 42 the last knights were exchanged and the engines started to shuffle. Stockfish's eval was over 1 but it could make no progress, the game ended in a 50-move draw.