Monday, October 17, 2022

Season 23 premier division, final results

Final standings

Stockfish and Leela will play in the superfinal of season 23. Stockfish led from the start and gradually increased the gap to second place. It had no losses in the league, beating KomodoDragon in all 4 game pairs and beating Leela once. Leela and KomodoDragon raced for second place, each had one game pair win in their head to head games. The race was decided in the last round, KomodoDragon's loss to Stockfish meant that the scores were tied and Leela won on a tiebreak - mainly due to a better result against Stockfish. Leela returns to the superfinal, in season 22 it was KomodoDragon that had a better score.

rofChade and Berserk are relegated to league 1. As the division progressed they dropped further behind the other engines and there was little doubt they would not survive. Together they have only one game pair win, where rofChade beat Berserk. rofChade has been moving between league 1 and the premier division for the last several seasons, last season it finished 4th in the premier division - its best result so far. Berserk had hopes of surviving the premier division, based on its results in the last Swiss tournament. Apparently it is not ready for a multi-DRR event with the best TCEC engines.

The top3 engines were much better than the bottom5, winning 51/60 game pairs without loss. This is a recurring phenomenon in the premier division. KomodoDragon drew only one such game pair, compared to 4 each for Stockfish and Leela. This is why its score does not reflect its losses within the top3.

Ethereal finished 4th in the division, this is its best result in TCEC. In season 22 it was not able to advance to the premier division, finishing 5th in league 1. Since then it has improved significantly, though still not at the level of the top3.

The next TCEC event will be a match between KomodoDragon and Ethereal (bronze medal match?). Considering the results of the premier division this will probably be a one-sided event and KomodoDragon should win by a large margin. The superfinal will follow, it should be less one-sided than last season's superfinal but Stockfish is still the favorite to win.

Interesting games

game 170, Ethereal - Stoofvlees: Ethereal created a passer in the center with all the pieces still on the board. After a few exchanges Ethereal connected a second passer, then went a pawn up and evals started to increase. Ethereal placed a protected knight on d6, then used the threat of forking the queen in a combination that started with a rook offering and ended in a winning BN vs pawns ending. 

game 171, Stockfish - Berserk: The game started with a 22-ply book in the KID Saemisch variation, with a Q vs BB imbalance and black two pawns up. Evals increased from the start, Stockfish captured two pawns and created a central passer. Berserk regained some material and the engines reduced to a QN vs RBN position. After a few pawn trades and some shuffling Stockfish traded pieces and the game reached a N vs B ending. Material was not equal for long, Stockfish went two pawns up and created 3 passers. Berserk also had a passer but Stockfish queened first, the game ended in a tablease win.

game 178, Stockfish - rofChade: Stockfish captured a bishop for two pawns very early, the white king was exposed and protected by pieces. rofChade had its queen and a pawn very close to the white king but Stockfish kept its king safe and evals increased. rofChade gave material and the game reached a QRB vs QB position, black 3 pawns up and still chasing the white king. rofChade captured another pawn, it took Stockfish 30 moves to get its king out of the way and exchange queens. The black pawns fell one by one and the game ended in a tablebase win.

game 179, Leela - Stoofvlees: Leela's eval increased quickly after the start, it gave a bishop for 3 pawns and exposed the black king. Stoofvlees lost a knight while defending its king, the engines reduced to a RN vs RB position with white two pawns up. Stoofvlees captured no less than 4 white pawns, creating 3 connected pawns on the queen side. However, Leela created a central passer and Stoofvlees gave the rook to stop it, followed by mate.

game 180, KomodoDragon - Berserk: Berserk captured a pawn on the king side, KomodoDragon castled long and its eval jumped. The white rooks moved to the king side, Berserk tried to get its king away but couldn't. KomodoDragon opened the h file and gave a rook for a bishop, then used a mate threat to capture a rook. The engines exchanged queens and the game reached a RBN vs RN position with black two pawns up. Berserk had passers on the king side, after a while KomodoDragon managed to capture a pawn on the queen side and create a passer. The black king was pushed to the corner, the engines continued to trade pawns until only the white passer remained. Berserk could not stop the advancing passer, the game ended in a tablebase win. 

game 182, Stoofvlees - KomodoDragon: Stoofvlees had an advantage in a Q vs RBN imbalance, 3 pawns up with two passers. It chose to exchange a pair of rooks and lost one passer, evals started to go down. Stoofvlees lost a bishop for the second passer and held a draw in a Q vs RN ending.

game 185, Stockfish - SlowChess: The center was locked, the engines exchanged pieces and evals were stable for a while. Stockfish's eval jumped after SlowChess opened the king side, the game reached a RB vs RB position. Stockfish shifted to the queen side, it gave two pawns and created a central passer. After regaining a pawn Stockfish pinned the black bishop on the back rank, by the time SlowChess freed its bishop Stockfish connected a second passer. SlowChess traded bishops but couldn't prevent a queening, game over.

game 187, KomodoDragon - rofChade: There were no pawn exchanges after the start and only one minor piece exchange. Evals were stable until move 37, a pawn exchange opened the a file and KomodoDragon went a pawn up. The engines shuffled for a while, after move 70 evals started to increase as KomodoDragon prepared an attack on the king side. After move 82 a series of exchanges opened the king side, rofChade gave a rook for a knight and the engines reduced to a RB vs BN position. The engines traded pawns, both had passers that seemed equally dangerous. However, both engines agreed that KomodoDragon was winning, the game ended in a tablebase win that included both engines queening and a queen ending with white a pawn up. 

game 196, Stoofvlees - rofChade: There were no exchanges until move 19, then the engines exchanged a pair of pawns and opened a file on the queen side. They later exchanged a pair of rooks through the open file. There was a long period of mostly shuffling, including a few pawn moves and a bishop exchange, evals slowly increased. Stoofvlees pushed pawns on the king side and on move 70 the king side finally opened. rofChade gave a knight for two pawns to keep its king safe, then it gave a rook for a bishop. After exchanging queens only RN vs N remained, Stoofvlees created an unstoppable passer to win.

Standings after RR7: Stockfish +18, Leela KomodoDragon +13, Ethereal 0, Stoofvlees -7, SlowChess -9, rofChade Berserk -14. Leela failed to win as white against Ethereal and SlowChess, within the top3 all games were drawn. KomodoDragon has a good chance of finishing second. Berserk and rofChade will surely be relegated.

game 201, KomodoDragon - SlowChess: The engines castled in opposite directions, evals increased from the start. The engines exchanged minor pieces and opened a file in the center, KomodoDragon moved its queen to the king side and pinned a bishop that protected the black king. SlowChess gave a pawn and opened the queen side, KomodoDragon blocked the files and moved more pieces to the king side. KomodoDragon captured another pawn and then reduced to a N vs R position. It used an unstoppable passer to win.

game 202, Leela - Berserk: The engines played out a long PV agreement where the queens were exchanged and Leela captured a rook for a knight and pawn. Evals slowly increased as the engines arranged their pawns, then Leela's eval jumped when in a series of exchanges the game reached a RN vs R ending. Berserk was two pawns up with a central passer, Leela captured the passer and created one of its own that Berserk couldn't stop. the game ended in a tablebase win.

game 203, Stockfish - Stoofvlees: The center was locked, Stockfish castled long and Stoofvlees pushed pawns on the queen side. Stockfish pushed pawns on the king side, Stoofvlees castled short and Stockfish thought this was the wrong time to do it. Stockfish's eval jumped as it sacrificed a bishop for a pawn, then a rook for a bishop and opened the king side. Stoofvlees tried to counter on the queen side but was not strong enough. Stoofvlees gave material to protect its king, its queen and rook were too far to help. Stockfish mated with queen and knight. 

game 204, Ethereal - rofChade: There was one pawn pair exchanged after the start, evals were stable until move 24 when Ethereal's eval jumped though the advantage was not apparent. The engines exchanged a few pawns and pieces including queens, then mostly shuffled while evals increased slowly. On move 58 Ethereal went a pawn up, rofChade pushed a pawn that became a passer. The game reached a RB vs RN position and Ethereal captured the black passer. Ethereal played patiently, it slowly captured black pawns until by move 100 all the black pawns were gone and it was 4 pawns up. The game reached a tablebase win not long after.

game 210, KomodoDragon - Stoofvlees: Stoofvlees captured an early pawn, but it moved its king without castling. There were many early exchanges and the game reached a QR vs QR position on move 19. Evals jumped on move 22, KomodoDragon regained the pawn and threatened the exposed black king. Before long the black king had to run with the white pieces chasing, KomodoDragon won material and finally mated.

game 211, Leela - rofChade: The engines castled in opposite directions, Leela pushed pawns on the king side. There were many early exchanges and the game reached a RB vs RN position on move 24. Leela went a pawn up, rofChade created a passer on the king side while Leela had a 3 vs 1 pawn majority on the queen side. Leela won the pawn race and queened first, the game ended in a tablebase win.

game 212, Stockfish - Ethereal: There were no exchanges until move 19. A few pawn exchanges opened the queen side and evals started to increase. Ethereal went a a pawn up with a passer on the queen side, after exchanging queens Stockfish regained the pawn and the game reached a RBB vs RNN position. The white king moved forward and the white bishops covered many squares in the open board. Ethereal moved its king to support the passer, this opened the way for the white king to attack the king side. Stockfish created an unstoppable passer, Ethereal gave a rook for a bishop to capture it. Stockfish created another passer, both engines queened but Ethereal lost material and was mated.

Three rounds to go, Leela and KomodoDragon have the same score in joint second place. Leela has a tiebreak advantage because it only lost to Stockfish once compared to KomodoDragon's 3 losses. Leela's remaining games are white against Stockfish, black against Ethereal and SlowChess. KomodoDragon's remaining games are white against Ethereal, black against Stockfish and rofChade. KomodoDragon has a good chance of reaching the superfinal if it holds against Stockfish, which it has not been able to do so far in this division.

game 216, Stoofvlees - Berserk: Evals were stable after the start while the engines exchanged a few pawns and minor pieces. Berserk went a pawn up and it had connected passers on the queen side, Stoofvlees had a 2 vs 1 pawn majority also on the queen side. Evals started to increase, Stoofvlees captured one of the passers and created a passer of its own. The game reached a RB vs RN position, Stoofvlees used a mate threat to exchange rooks. Berserk had to block the white passer with its knight, Stoofvlees gave its bishop and captured the remaining black pawns. The game ended in a tablebase win.

game 219, KomodoDragon - Ethereal: The engines opened the king side, KomodoDragon castled long and Ethereal kept its king uncastled. Ethereal captured a pawn on the king side, KomodoDragon captured a pawn on the queen side and created a passer. Ethereal captured a pawn in the center but evals started to increase. Ethereal gave a rook for a knight to capture the white passer, after exchanging queens KomodoDragon again had a passer on the queen side. The game reached a RB vs BN position, Ethereal had 3 passers on the king side but it was too busy with blocking the white passer. KomodoDragon captured pawns, it got a bishop for the passer and the game ended in a tablebase win.

Leela only managed a draw against Stockfish. Before the last round KomodoDragon is in second place 0.5 points ahead of Leela.

game 221, SlowChess - Leela: Evals came down from the start, Leela had no problems equalizing and the game seemed to be heading for a draw. There was some excitement when Leela's evals became negative after move 32, close to 0 at first and then jumping a little. Leela threatened to create a passer on the queen side, it doubled rooks in an open file and for a few moves SlowChess' eval was negative as well. However SlowChess managed to hold, most pieces were exchanged and evals came back down.

game 222, Stockfish - KomodoDragon: See featured game below. 

Stockfish beat KomodoDragon for the fourth game pair in a row. As a result Leela moves to second place on a tiebreak. 

game 223, Ethereal - Berserk: Ethereal's eval started to increase after it gave a pawn and opened a file in the center. Ethereal created a passer in the center through an exchange, then it regained the pawn and placed all the major pieces on the open file. Berserk exchanged pieces and the game reached a RN vs RN position. Ethereal went a pawn up though it lost the passer, the white king moved forward to the center of the board. Ethereal managed to capture all the black pawns and was 3 pawns up, the game ended in a tablebase win.

Featured game: Stockfish - KomodoDragon
game 222

After the start the engines lined up their pawns on the queen side. Starting from move 14 the engines played out a long PV agreement, they opened the d file in the center and exchanged queens. Towards the end of the PV agreement evals started to increase though KomodoDragon was a pawn up with a doubled central passer. 

Stockfish moved its knight to a5 and attacked the weak black pawn on c6. KomodoDragon protected the pawn with its bishop, which became trapped in the corner. The game reached a RBN vs RBN position and Stockfish regained the pawn. KomodoDragon tried to keep the files blocked so the white rook couldn't attack. KomodoDragon moved its rook forward and there it became trapped in the center. 

Stockfish had too many threats for KomodoDragon to defend, in the end Stockfish captured the c6 pawn and won the rook for a bishop. The black bishop was released from the trap in the corner. Stockfish moved its rook to the 7th rank and pushed its c pawn forward. KomodoDragon had to give its knight to avoid a queening.  

The game ended a few moved later in a tablebase win. 


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