Thursday, April 25, 2019

Season 15 premier division after RR5

Crosstable after RR5

Stockfish and Leela continue to lead, there were no significant changes at the top of the table. Stockfish had an advantage in their 5th game but it too ended a draw. Leela has a chance to win in their last head to head game in RR6.

At the bottom Ethereal had its best RR with a 3.5/7 score, including a win against Fire. Ethereal and Fire are still last but Ethereal closed the gap between them to 0.5 points.

In the middle section Komodo and AllieStein pulled ahead of Houdini and KomodoMCTS. AllieStein got a free half point when KomodoMCTS crashed in a drawn position.

For the second time in the division there were two consecutive network crashes and the GPU server had to be reset. 

A few interesting games

AllieStein - Ethereal: AllieStein had an eval over 1 from the start, and it increased quickly. AllieStein gave two pawns and then won a knight. Ethereal had three pawns as compensation but evals were very high. After exchanging queens AllieStein got one pawn back and the game reached a RRB vs RR position. The endgame took a very long time, the engines mostly shuffled. In the end AllieStein found the winning path, the game was adjudicated in a RB vs R position on move 114.

Houdini - AllieStein: The network crashed on move 14, the game was later resumed and resulted in a draw.

Leela - Fire: The network crashed on move 45 and the game was resumed later. Leela pushed pawns on the king side and opened a file near the black king. Queens were off early and Leela moved its king without castling, Fire captured a pawn but its LS bishop was almost trapped and Leela's eval increased to 4. The game reached a RBN vs RBB position on move 26,  the black pieces were defensive and the white knight dominated the center. After some preparation Leela created a queen side passer, Fire stopped it for a bishop when it got to the 6th rank. The endgame was slow, it took Leela almost 50 moves to capture all the black pawns. Leela pushed a passer to the 7th rank and the game was adjudicated.

Fire - Komodo: There were very few exchanges after the start, evals were close to 0 in a closed position. On move 37 Komodo opened a file on the queen side and its negative eval started to increase. The engines exchanged a pair of rooks and shuffled for a while, then exchanged Q for RB on move 58. Komodo's eval became constant, the game reached a RB vs Q ending on move 70 and it looked as though Komodo can't find a win. It took 40 moves for Komodo's eval to move again, 20 more moves for Komodo to capture a pawn. The game was adjudicated on move 137.  

Stockfish - Houdini: Stockfish had an eval advantage from the start, evals slowly increased but mostly stayed under 1. The game reached a RBB vs RBN position on move 34, Stockfish had a pawn majority on the queen side and Houdini had a passer. Stockfish's eval started to increase, it gave a pawn and used its bishops to take control of the center and trap the black knight on the h file. By the time Houdini freed its knight Stockfish's eval was over 5, the black king was surrounded and a pair of white pawns moved forward in the center. Houdini lost the knight and the game was adjudicated as it was about to lose more material.

Komodo - AllieStein: See featured game below.

AllieStein - KomodoMCTS: The game reached a RB vs RB position on move 30. AllieStein's eval peaked over 3 but it did not find a way to win. The engines exchanged rooks and the bishops were of the same color, AllieStein made no progress and the engines shuffled for a long time. Unfortunately KomodoMCTS crashed and lost.

Stockfish - Leela: Stockfish had an eval advantage under 1 from the start. On move 20 it created an advanced central passer, evals climbed over 1 and it seemed Stockfish had a real chance. Evals then dropped, Leela exchanged pieces until reaching a drawn R vs BN ending.

Ethereal - Fire: The game reached a QBN vs QBN position on move 44, with the center blocked and the king side open. Fire played passively and the white king charged forward. The black king was far on the queen side and Fire was outnumbered on the king side. Ethereal trapped the black bishop on the 8th rank and eventually captured it with the king (!!). The game was adjuducated a few moves later.

Leela - Komodo: Leela's eval climbed over 1 from the start. There were many early exchanges and only RRB vs RRN remained on move 22. Leela's eval increased as it pushed a passer on the king side, Komodo captured it but gave a rook for a bishop. It took Leela a while to capture two pawns so it had passers on both sides, when they started marching the game was adjudicated.

Featured game: Komodo - AllieStein
Premier division, game 127
Link to game on TCEC

Komodo had an eval advantage from the start of about 1. There were several early exchanges, on move 20 AllieStein captured a pawn with a bishop, but didn't see what was coming. Komodo's eval jumped near 2 after it attacked the bishop, forcing the black queen to stay on the diagonal to defend it.

Komodo attacked the black queen and controlled where it could go, there were only a few free squares available for it. After a few moves Komodo forced a rook exchange and won the black bishop, its eval over 3 in a QRB vs QR position.

After exchanging queens AllieStein saw it was losing. It preferred to give up its remaining rook than to keep fighting.

Mate was close when the game was adjudicated.

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