Season 19 premier division, after RR2

Standings after RR2

Stockfish leads with a 1 point gap. It started with 7 draws but had 4 wins in RR2. Leela, AllieStein and Stoofvlees are in the chase group. The top 4 engines appear to be a class of their own as in last season. This season Stockfish is using a NN for evaluation, the results show that this is the best evaluation currently available.

The bottom 4 engines are also close together. Komodo is currently last, this may be the first time it drops out of the top league since season 4.

The first RR was very drawish with only 4 decisive games. The organizers discovered that many of the openings were not supposed to be used in the premier division. The decision was to finish the DRR without change, fix the openings for the following games and add a 4th DRR to compensate for the initial drawishness. 

Interesting games

Game 4, Stoofvlees - Komodo: Evals started to climb after Stoofvlees gave a pawn and created a pawn majority on the queen side. The engines exchanged queens, and Stoofvlees regained the pawn and created a pawn majority on the king side in a RRB vs RRB position. Stoofvlees exchanged a pair of rooks and captured a pawn, the game was adjudicated before Komodo lost more material.

Game 6, Ethereal - Stoofvlees: Ethereal gave a rook for a bishop and pawn yet had a small eval advantage. Stoofvlees chose to give the material back, leading to a QRB vs QRB position with white a pawn up and evals over 2. Stoofvlees focused on the queen side pawns and neglected its king, it created connected passers and thought it was relatively safe. Ethereal saw further ahead and realized it was winning, it used the exposed black king to reduce to a queen ending with a passer on the 7th rank and the game was adjudicated.

Game 9, Leela - ScorpioNN: ScorpioNN grabbed a pawn with its bishop and Leela trapped the bishop. ScorpioNN gave a rook for a bishop before the trapped bishop could be saved, the game reached a RR vs RB position. Evals stayed around 1 for a while, then started to increase after Leela had only one pawn left, a passer supported by the rooks. Leela slowly pushed the passer forward, the black king was also pushed back. In the end the rooks were enough for a mate without queening the pawn.

Game 27, Ethereal - Leela: Ethereal gave a knight for 2 pawns, evals were close to 0 and the draw rule was a few moves away when Leela's (negative) eval started to increase. The white king was exposed and Leela found a way to exploit this fact, including an knight sacrifice that Ethereal refused. It was difficult for me to follow Leela's threats or understand Ethereal's choice of moves, evals rose quickly until Ethereal lost more material in a series of exchanges. Leela was a rook up and the game was adjudicated.

Scores after RR1: Leela +2, Ethereal Stockfish Stoofvlees AllieStein Fire +0, ScorpioNN Komodo -1. Only 4/28 decisive games. Leela leads with two wins, 7 draws for Stockfish, AllieStein and Fire.

Game 34, Stoofvlees - Ethereal: Stoofvlees had a space advantage, the center was blocked, a bishop and a knight on the 5th rank restricted Ethereal's movement. Evals increased while Ethereal tried to open the position and exchange pieces, Stoofvlees captured a rook for a bishop and only RRN vs RBN were left. Stoofvlees pushed a passer to the 7th rank and eventually Ethereal lost the knight to stop it. Two white wins in this opening.

Game 38, Stockfish - AllieStein: See featured game below.

Game 45, ScorpioNN - AllieStein: ScorpioNN was a pawn up with doubled queen side passers, but its pawn structure was weak. AllieStein stopped one passer on the 7th rank, went a pawn up and reduced to a RB vs RB ending. AllieStein played with a lot of patience, it managed to capture another pawn after 20 moves, then exchanged rooks 10 moves later. The bishops were of opposite color, but ScorpioNN couldn't block the 3 connected black passers supported by the black king.

Game 47, Stockfish - Komodo: Stockfish's eval started at 1 and gradually increased. Stockfish pushed pawns on the queen side and Komodo had difficulties developing its pieces. For a while the black queen was almost trapped on the king side, then the game redcued to a QRB vs QRB position. The black king was exposed, after exchanging rooks Stockfish used checks to capture 2 pawns and reach a winning same color bishop ending.

Game 50, Ethereal - Stockfish: Stockfish's (negative) eval jumped over 2 early, it eliminated the white king side pawns and Ethereal hid its king behind a black pawn. Ethereal exchanged pieces to make its king safe, the game reached a RN vs RB position with Stockfish 2 pawns up. The white knight blocked two passers on the king side, after some shuffling and a rook exchange Stockfish shifted its king to the queen side and captured another pawn. The game was adjudicated shortly afterwards.

Game 52, Stoofvlees - AllieStein: Evals were low all through the game, despite an early knight sacrifice by Stoofvlees. Stoofvlees attacked on the king side and traded RB for Q, AllieStein found a perpetual check draw. 

Game 54, AllieStein - Komodo: AllieStein was two pawns down but it trapped a black bishop in the corner. Within a few moves AllieStein's eval climbed to double digits, it exchanged queens and it had an extra piece to use. AllieStein created a queen side passer, Komodo finally sacrificed a knight for pawns to free its bishop, then it gave the bishop to stop the passer. AllieStein was up two bishops for 4 pawns, it continued to win material before the game was adjudicated. 

Game 56, Stockfish - Fire: There were only a few exchanges and the engines mostly shuffled for a long time. On move 58 Stockfish's eval started to jump quickly, in a long series of exchanges Stockfish created connected passers on the king side and reduced to a B vs N ending. Fire had to focus on the advancing passers, this allowed Stockfish to go 2 pawns up and win.

Featured game: Stockfish - AllieStein
Premier division, game 38
Link to game on TCEC

Stockfish created connected passers on the queen side early, its eval was over 1 for a while and then dropped down. AllieStein pushed pawns on the king side facing the white king, Stockfish had to be careful to keep its king safe and it seemed AllieStein had enough compensation for the white passers.

Stockfish captured a pawn on the queen side, AllieStein threatened to open the king side with a knight sacrifice. Stockfish refused to take and instead gave a rook for a knight, its king still in danger. Evals suddenly jumped over 2 on move 35, AllieStein did not expect Stockfish's move and immediately saw it was in trouble. Stockfish equalized the material and reduced to a RBN vs RBN position.

The white king was out of danger and the passers on the queen side became very strong. The black bishop was almost trapped, after a few moves Stockfish captured it and the game was adjudicated.