Season 17 league 1 playoff, after RR2

Crosstable after RR2



For the first time in season 17 CPU engines are playing against GPU engines. Four out of the six engines in this playoff will move on to play in the Premier League, the highest level  TCEC tournament.

At the halfway point it appears that Fire and KomodoMCTS will promote while ChessFighterNN is probably going to finish last. The middle group of ScorpioNN, rofChade and Ethereal are in the race for two promotion spots.

The GPU and CPU engines have very different evaluation functions. The games in this league tend to be longer than in previous stages, the engines take longer to decrease evals in drawn results. ChessFighterNN's eval rarely increases beyond 10 and as a result its games can continue until mate (4 games so far). There was one crash by ScorpioNN, but that was due to a wrong parameter setting. The parameter was fixed and the game was resumed without a problem.

Notable games

Game 3, ScorpioNN - KomodoMCTS: ScorpioNN thought it was better in a closed position with blocked pawn lines. The engines shuffled from move 28 and ScorpioNN avoided the 50-move draw with a pawn sacrifice. The engines continued to shuffle, though ScorpioNN allowed a black pawn to reach the 2nd rank. Then quite suddenly KomodoMCTS' eval jumped, it found a mating sequence that ScorpioNN overlooked, perhaps due to a queen sacrifice.
Game 10, ChessFighterNN - rofChade: ChessFighterNN was sure it was better after the opening, its eval peaked over 3. rofChade traded 2 knights for a rook and pawn, it exposed the white king to attack along the long diagonal. Evals dropped to 0, then ChessFighterNN blundered when it failed to consider a rook for knight sacrifice by rofChade. The white king came under attack and ChessFighterNN was forced to trade down to a rook ending. rofChade was a pawn up with connected passers, both engines queened a pawn but rofChade was first. It was able to promote a second pawn and win.
Game 15, rofChade - Ethereal: Evals climbed above 1, rofChade had more space and it trapped one of the black rooks for a while. After several exchanges the game reached a RN vs RN position, rofChade with a pawn up and a queen side passer. Ethereal exchanged rooks and that was a possible blunder, rofChade's eval jumped quickly. At first Ethereal thought it was safe, when its eval reacted it was too late, the white passer was unstoppable and the game was adjudicated.
Game 21, Fire - Ethereal: Fire had a space advantage, the first piece was exchanged on move 31, Ethereal had a passer but couldn't push it forward. After another minor was exchanged Fire had strong central pawns and a bishop pair, the black king became a target. Several exchanges cleared the center, Fire was a pawn up and it pushed a passer forward. Ethereal gave a rook for a bishop to remove the passer, Fire converted the RRB vs RBN ending, the game was adjudicated 10 moves later.
Game 30, Ethereal - rofChade: The game reached a QB vs QB ending, Ethereal with a pawn up. Ethereal's eval was close to 2 but it couldn't find the win, rofChade held and the game was adjudicated a draw on move 137.