Saturday, April 20, 2019

Season 15 premier division after RR3

Crosstable after RR3

Stockfish and Leela are leading and it is safe to predict they will win the division. Stockfish had 4 wins in RR3 and Leela only 1, the gap between them is 2 points. However, we have seen in season 14 that the results of the premier division are not a good predictor of the superfinal outcome.

Fire and Ethereal are at the bottom and are surely going to be relegated.

Houdini and Komodo lost their first game in RR3, both lost to Stockfish. Fire won its first game off a terrible blunder by AllieStein. There is still only one decisive game that doesn't involve Stockfish, Leela, Fire or Ethereal, out of a total of 18 games.

A few interesting games

Komodo - Stockfish: See featured game below.

AllieStein - Ethereal: AllieStein had an eval over 1 from the start. Ethereal gave a rook for a bishop and pawns and evals increased quickly. By move 24 AllieStein's eval was over 4 and Ethereal had a bishop trapped in the corner. The engines shuffled for a while and then exchanged queens. Ethereal gave its trapped bishop for pawns, the game reached a RRB vs RN position with Ethereal 4 pawns up and evals over 10. AllieStein took its time, the game was adjudicated 30 moves later.

Stockfish - Ethereal: Stockfish had a small eval advantage for 30 moves, then started to increase gradually. Ethereal had two isolated pawns on the queen side, 2 weak pawns on the king side and its DS bishop was trapped. Ethereal went up a pawn but evals were over 1.5.  Stockfish continued to build pressure, eventually Ethreal's defense broke down. Stockfish opened the king side, won two pawns and created an advanced passer. Ethereal exchanged queens and lost a knight and the game was adjudicated. Back to back losses for Ethereal.

Stockfish - Houdini: Stockfish had an eval advantage that stayed around 1 for 45 moves. Houdini gave a rook for a bishop early in the game, it seemed to be holding for a long time and the engines shuffled for a while. Evals climbed a little when the engines exchanged pieces, with only RN vs BN remaining on move 62. The engines captured pawns gradually, in the end Stockfish gave the rook for a knight to get a winning endgame.

Leela - Ethereal: Leela started with an eval over 1 that increased quickly. Leela went a pawn up on move 25 after a series of exchanges, by move 40 the game reached a rook ending and Leela's eval was over 8. Leela pushed pawns forward and Ethereal couldn't stop them, the game was adjudicated with two white passers advancing.

Fire - Stockfish: Both engines had long pawn lines, the queen side and center were blocked, Stockfish had a negative eval around 1. Fire opened the queen side and exchanged queens, Stockfish's eval increased over 2. The game reached a RN vs RN position on move 47, Fire was a pawn up with passers on both sides but the white pawns were weak. Stockfish slowly captured pawns, the game was adjudicated with black 4 pawns up.

AllieStein - KomodoMCTS: AllieStein seemed to be heading for a win with eval over 3, yet somehow KomodoMCTS found a perpetual check draw.

Fire - AllieStein: Evals were close to 0 from the start. AllieStein gave a rook for a bishop on move 27, yet it thought it was better with a pawn on h3 and the only remaining knight in a closed position. The game reached a QRB vs QBN position on move 39 and the engines started to shuffle. AllieStein's negative eval went over 2 and it extended the shuffle with pawn moves and exchanges. Then on move 189, it blundered badly and got its king in a mating net. Fire captured the black queen and won easily.

Featured game: Komodo - Stockfish
Premier division, game 57
Link to game on TCEC

Evals were close to 0 after the start. Stockfish's (negative) eval increased to around 1 after Komodo opened a file on the queen side. Stockfish concentrated forces on the king side but the white king was safe enough. There were a few exchanges and evals remained more or less constant.

The engines mostly shuffled with very few exchanges and pawn moves for a long time. On move 74 Stockfish's eval went over 1.5 though nothing seemed to change. A few moves later Komodo's rook moved forward, probably a mistake. Stockfish saw an opportunity and sacrificed a bishop.

The king side opened and all the white pieces were badly placed, not able to help the white king and blocking its escape route. Within a few moves Stockfish took over the back rank and regained the material.

Stockfish drove the white king forward, the game was adjudicated with Komodo about to lose its queen.

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