Season 17 premier division, all engines, after 90 games

Crosstable after 90 games

There were only 3 decisive games in the first 30 games involving GPU engines, and only one of these was a CPU-GPU match. As a result the CPU engine standings did not change. In the GPU part of the table Leela and AllieStein have one win each, a better win rate than Fire which is currently in 2nd place. Still very early to make predictions.

We have seen the characteristic properties of GPU engines: longer games, mate on the board, the inability to convert won endgames. The increase in draw rate was unexpected but it may still improve.

There were two network crashes in CPU-GPU games.

Interesting games

Game 64, Fire - AllieStein: AllieStein was sure it was better in a BN vs RN position with white 3 pawns up. It gave the knight for pawns and pushed a passer to the 2nd rank, its eval over (negative) 10 for a few moves. Fire was willing to trade its bishop for the passer in case it tried to promote, and AllieStein knew this would lead to a draw. Instead the engines shuffled for almost 50 moves, and only then AllieStein made the trade, its eval coming down to around 1.5. Still AllieStein wouldn't give up and the game ended in a 50-move draw on move 161.


Game 69, Komodo - ScorpioNN: ScorpioNN was a pawn up and its (negative) eval kept increasing. ScorpioNN's eval peaked over 4, Komodo also thought it was behind with an eval of 2. It seemed ScorpioNN could attack on the king side, but it just kept shuffling as evals slowly came down. The engines started to exchange everything, the game ended in a tablebase draw on move 150.

Game 73, ScorpioNN - AllieStein: AllieStein captured a pawn with its queen and then retreated, there was no eval change so the pawn was not poisoned. On the contrary, its (negative) eval started to increase. ScorpioNN tried to press on the queen side, AllieStein gave a rook for a knight and broke through the center. After some shuffling AllieStein captured another pawn, the game reached a QR vs QB position with black 3 pawns up. The black pawns moved forward and ScorpioNN couldn't stop one from promoting, the game ended with mate on the board. First decisive game for a GPU engine.

Game 83, Leela - Stoofvlees: Stoofvlees gave a lot of material early in the game, it was down a full rook on move 25. The white king was on the run from the black queen and bishops, Leela slowly untangled its pieces and then the material advantage became evident. Stoofvlees tried to push a passer and lost it in the end, it tried giving checks with its queen but Leela found safety for its king. The game ended with mate on the board.

Game 84, ScorpioNN - Stoofvlees: See featured game below.

Game 87, KomodoMCTS - ScorpioNN: There were no exchanges in the first 25 moves. The center was blocked and the engines opened files in the flanks. KomodoMCTS was active on the queen side and evals started to increase, ScorpioNN was weak there with a blocked pawn on c7 and an almost trapped bishop on c8. KomodoMCTS broke through the queen side, ScorpioNN countered on the king side and there was a massive exchange. The game reached a queen ending, KomodoMCTS was a pawn up and its pawns were more advanced. The game ended in mate.


Featured game: ScorpioNN - Stoofvlees
Premier division, game 84
Link to game on TCEC

ScorpioNN had a space advantage, it pushed its pawns forward and the black pieces had to move back. Stoofvlees gave material to open the board and to counter with an attack on the exposed white king. Evals went over 2, Stoofvlees was a rook down and both engines didn't believe the king side attack compensated for the material loss.

ScorpioNN avoided threats of a perpetual check, Stoofvlees chased the white king but it escaped to the queen side where it had the protection of its pieces. Along the way Stoofvlees captured a few pawns. ScorpioNN forced a queen exchange that stopped the threats on the white king. The game reached a RBN vs BN position with black 4 pawns up.

All evals were very high, ScorpioNN just had to get rid of a few pawns and exchanged pieces, it seemed an easy win. ScorpioNN went after the black bishop first, it exchanged its knight for it, losing its last pawn in the process. Both engines seemed less sure about the outcome, their evals drifted down.

Stoofvlees kept three pawns on the king side, and together with the knight it built a fortress that ScorpioNN couldn't break. The white king stood in the way of the pawns without moving, and the white pieces could not mate the black king without its help. The engines just shuffled for 50 moves, and ScorpioNN ended the game by giving the bishop for a pawn. The draw was quite unbelievable.