Season 16 premier division after RR2

Crosstable after RR2

After the first double RR is over the top of the table is what we have seen in the last few seasons, with Stockfish in front and Leela second, already with a small gap to the other engines. Both Stockfish and Leela had a +1 score in RR2, not very high but still no other engine scored better and this was enough to keep them in the lead.

At the bottom KomodoMCTS and ScorpioNN continue to lose games to all other engines, they are surely on their way to league 1.

There was an unusual Stockfish crash. It happened in a drawn position in the game against Houdini, so Houdini has not won a real game yet and it would have had a negative score if Stockfish hadn't crashed. The Stockfish developers think the crash may have been the result of a problem in an external library, not the Stockfish code. This means that such a crash might happen again. A rate of one crash in 2 RRs could be too high and Stockfish might be in danger of disqualification.

A few interesting games

AllieStein - KomodoMCTS: AllieStein had a significant eval advantage with even material, perhaps due to an active bishop pair in an open position and the exposed black king. AllieStein's eval peaked over 10, it was a pawn up and the game reduced to a RN vs RN position. KomodoMCTS found a defense by giving checks and using a mate threat, the game reached a drawn rook endgame.

KomodoMCTS - ScorpioNN: The position looked drawn when ScorpioNN allowed KomodoMCTS to reduce to a king and pawns endgame. Both engines managed to promote a pawn to a queen, KomodoMCTS was a pawn up and this was enough to force a win. First win for KomodoMCTS in the division.

Stockfish - AllieStein: The engines shuffled in a closed position and were close to a 50-move draw twice. Evals started to increase with very little time left, the game reached a RN vs RB position. AllieStein was a pawn up but Stockfish had an advanced passer supported by the king and its pieces were much more active. AllieStein couldn't stop the passer without losing a piece, and the game was adjudicated.

Stoofvlees - ScorpioNN: Stoofvlees had an eval around 1 from the start. The game reached a QRB vs QRB position, Stoofvlees had a strong pawn line while ScorpioNN had a trapped bishop and two isolated pawns on the queen side. ScorpioNN gave two pawns and tried to attack the white king. In desperation ScorpioNN sacrificed a rook but couldn't force a perpetual check, Stoofvlees' material advantage gave it the win.

KomodoMCTS - Leela: Leela pushed a pawn to h3, its signature thorn pawn move, and its (negative) eval went over 1. It captured a pawn and created a passer on the queen side, while KomodoMCTS had a passer in the center. The engines got rid of the passers and reduced to a RB vs RN position, Leela captured another pawn and that was enough for a win. Two wins for Leela in this opening.

Houdini - Stockfish: The game reduced to an opposite color bishop ending and was heading for a draw when Stockfish crashed.

AllieStein - Komodo: See featured game below.

Stockfish - KomodoMCTS: Stockfish castled long, then gave a rook for a knight early and opened the king side. The black king walked to the queen side to find safety, the engines reduced to a QR vs QR position with Stockfish two pawns up. After exchanging queens the white passers won the game.

Featured game: AllieStein - Komodo
Premier division, game 52
Link to game on TCEC

AllieStein was up a knight for a pawn early in the game. Komodo's rooks controlled the center files and its queen threatened the exposed white king. However, Komodo's attack was not strong enough to compensate for the piece.

AllieStein's eval increased rapidly as the engines exchanged pieces until reaching a QBB vs QN position, with AllieStein two pawns down. The LS bishop was restricted by the black pawns and knight.

Komodo pushed its king side pawns and tried to blockade the white bishops and king. After a while AllieStein forced a queen exchange and only BB vs N remained.

The white bishops targeted the black pawns, they slowly cleared a few and made more space for them to move. Komodo defended for more than 30 moves but eventually agreed it was losing and the game was adjudicated. This is the first loss for Komodo in the division.