Season 16 premier division after RR1

I'm back from sick leave and gradually getting better. It is going to be hard work to catch up with all the games played so far in the premier division, but we'll get there eventually.

Crosstable after RR1



Stockfish is leading the table with a +3 score. Leela and Komodo are close behind with +2, Komodo doing better than expected in the first RR.

At the bottom are KomodoMCTS and ScorpioNN, with a total of 7 losses of 12 games against the other 6 engines. Only Houdini does not have a win against at least one of them.

Stoofvlees is the only engine with at least one win and one loss.

TCEC has a new web page which is supposed to be more stable. The live engine analysis appears only in the new website. There is also a new archive and the premier division games can be found only there. Here are the addresses:
New site: https://tcec-chess.com/
New archive: https://www.tcec-chess.com/archive.html
 
A few interesting games

Leela - ScorpioNN: Leela was up a pawn in a QRR vs QRR position. It gave the pawn back and created a passer, evals climbing over 2 at this point. A pawn exchange later Leela had two connected passers on the queen side and ScorpioNN also had to protect its king. The engines exchanged queens and the double rook ending was a win for Leela.

Stockfish - Stoofvlees: See featured game below.

Komodo - KomodoMCTS: Most of the black pieces were on the queen side when Komodo started attacking on the king side. It gave a knight to open a file, KomodoMCTS' king had to face all the white major pieces almost without support. KomodoMCTS gave its queen for a rook to save its king, the game reached a Q vs RN position and Komodo won.

KomodoMCTS - AllieStein: The game reached a RB vs RB position that appeared completely drawn. The engines exchanged bishops just before the 50-move mark, then exchanged rooks. Unexpectedly KomodoMCTS blundered the endgame, and AllieStein used zugzwang to capture two pawns and win.

Stockfish - ScorpioNN: There were only a few exchanges in the first 75 moves and evals stayed low. Stockfish gave two pawns and created a passer on the queen side, ScorpioNN eventually gave a knight to get rid of the passer. The game reached a QN vs Q position, Stockfish captured a pawn and then forced a queen exchange to get a tablebase win.

Komodo - ScorpioNN: ScorpioNN gave up a pawn for no apparent reason, perhaps it thought its king side pressure was some compensation. Komodo defended easily, captured a second pawn and pushed a passer to the 7th rank. ScorpioNN gave material to keep its attack alive, the game was adjudicated a few moves later.

KomodoMCTS - Stoofvlees: Stoofvlees developed a strong bishop pair and KomodoMCTS gave a rook to remove one of them. The game reached a difficult BN vs RB endgame with one pawn for each engine, Stoofvlees managed to capture the white knight after 30 moves and get a tablebase win.

Leela - KomodoMCTS: KomodoMCTS had initiative on the queen side, with a rook controlling an open file. It paid less attention to the king side, and when Leela opened a file there the black king was in danger. Leela increased the pressure and the black king fled to the center. Leela sacrificed a queen for a knight, KomodoMCTS had to give its queen to avoid mate, the RBN vs RN ending was a win for Leela.

Stockfish - Houdini: Stockfish gave a rook for a knight temporarily, then got the material back and created a passer. The game reached a QRB vs QRB position, after exchanging queens Stockfish pushed the passer to the 7th rank. Houdini had to give its bishop to stop the passer, leading to a won endgame for white.

AllieStein - ScorpioNN: AllieStein captured a rook for a bishop, its eval peaked close to 9 in a RB vs NN position. The engines started to shuffle and AlllieStein could not find a way to break ScorpioNN's defense. The game ended with a 50 move draw.

Featured game: Stockfish - Stoofvlees
Premier division, game 2
Link to game on TCEC

Stockfish went up a pawn on move 23 with a 3 to 1 pawn majority on the queen side, evals stayed below 1.


 
Stockfish pushed its queen side pawns forward and evals went up. Stoofvlees tried to counter with a passer in the center and pressure on the king side, it sacrificed a knight to expose the white king.

Stockfish calmly defended its king, Stoofvlees gave a rook for a bishop and increased the pressure but in the end the attack on the white king was not effective. Meanwhile Stockfish cleared the path for its pawns on the queen side.

The extra white rook together with one of the pawns queening led to a quick mate on the board for Stockfish.