Season 28 premier division final results

Final Standings

Stockfish and Leela will play in the season 28 superfinal. Stockfish had 6 game pair wins with no loss in the last DRR, its best DRR of the division. Its full score for the division is 19/28 game pair wins and two losses, against Leela and Integral. Leela had 4 wins and one loss in the last DRR, similar to its results in the previous DRRs. Altogether Leela had 13 game pair wins and 2 losses, against Stockfish and against Obsidian. 

In the first two DRRs it seemed that Integral may cause an upset and qualify for the superfinal. However in DRR3 it had two losses with no win, and it dropped to 4th place. In DRR4 Integral returned to form with 4 wins and one loss, enough to get back to 3rd place but not to catch up with Leela. This is still impressive considering that this is the first TCEC season for Integral, it started season 28 in the entrance league. PlentyChess also started in the entrance league and managed to finish 5th in the premier division, better than Berserk that was 3rd last season. 

This season we also saw Ethereal and KomodoDragon relegating from the premier division. Both engines have participated in the premier division for almost all their TCEC career, for KomodoDragon this is from the beginning of TCEC (when it was just Komodo) and for Ethereal this is from season 11. KomodoDragon was even a TCEC champion several times and a superfinalist in several more. The developers of Ethereal and KomodoDragon were busy with other projects, and now there are enough new engines which have better results.

Interesting games

game 169, Leela - Berserk: Leela's eval jumped from the start, Leela castled long and the engines exchanged queens. The black king was stuck in the center, Leela traded two minor pieces for a rook and two pawns. Leela pushed pawns on the queen side where it had a pawn majority, the game reached a RN vs BBN position. Leela created two connected passers, then exchanged minor pieces and added a 3rd passer. Berserk couldn't stop the passers, Leela queened twice and mated.

game 171, Stockfish - Ethereal: The game repeated game 169 for 29 plys (each group of 4 games in this DRR have the same book), Stockfish traded a rook and two pawns for two minor pieces and evals were increasing. The game reached a RN vs BNN position, then Stockfish exchanged a pair of knights. A pawn trade gave each engine a passer on the king side, the white passer was faster and Ethereal lost a bishop to stop it. Stockfish captured the black passer, then captured a pawn and created connected passers on the queen side. Ethereal couldn't prevent the queenings followed by mate. 

game 173, Berserk - Obsidian: The center was blocked, Obsidian gave a pawn and opened the queen side. For a while the white king could not castle, Berserk blocked the interfering bishop and castled. Berserk captured a second pawn, nothing came out of the black attack on the queen side. Berserk protected its passer on the a file, then it gave back a pawn and created a second passer in the center. Berserk pushed the passers so both were protected by a knight, the engines exchanged queens and the game reached a RBN vs RBN position. Obsidian couldn't stop a queening, it lost material and was mated.

game 177, PlentyChess - Berserk: The book for this group of 4 games had a bias for black. Berserk pushed pawns on the queen side and opened files. All the queen side pawns were gone except one white passer. Berserk also exchanged pawns on the king side and it created a passer in the center. PlentyChess exchanged queens and captured a pawn, both kings were exposed but Berserk had strong bishops targeting the white king. Berserk pushed the passer to the 2nd rank, blocked by a rook. PlentyChess couldn't get rid of the black passer, Berserk reduced to a RBB vs RBN position. PlentyChess lost material, it managed to capture the passer but had no pieces left and was mated. 

game 179, KomodoDragon - Integral: KomodoDragon castled long and the queen side remained closed. The engines exchanged pieces gradually and evals were mostly stable. On move 42 the queens were exchanged, then the engines traded pawns and KomodoDragon created a passer on the queen side. Integral moved a rook forward, evals jumped when KomodoDragon exchanged a pair of rooks. Integral exchanged a pair of pawns and created a passer in the center with strong support. KomodoDragon pushed its passer forward but Integral blocked with a bishop. KomodoDragon gave a knight to capture the black passer, the game reached a RB vs RBB position and the black bishops were very active. Integral captured white pawns, KomodoDragon lost more material and mate followed.

game 181, Berserk - Ethereal: Ethereal pushed a pawn to a3, Berserk completed a diagonal pawn block from the center to b6. A few exchanges disrupted the diagonal pawn line, then Berserk captured the a3 pawn and exchanged a pair of rooks. The game reached a QRB vs QRN position, Berserk gave the pawn back to open the center, then it gave a rook for a knight and improved its pawn majority on the queen side. Berserk gave two pawns, this created many black passers but also two connected white passers. Berserk used the exposed black king to capture 3 pawns, Ethereal gave back the rook for a bishop but couldn't prevent queenings and mate.

game 182, Integral - Obsidian: Obsidian did not push the a pawn, the diagonal pawn lines were formed but Integral kept some tension wih the b pawn on b5. Eventually Integral exchanged the b pawn and the c pawn became a passer. Obsidian captured the passer and lost a pawn in the center, the engines continued to exchange pieces until the game reached a QRR vs QRR position. Material was equal but Obsidian had an isolated pawn in the center. Integral exchanged queens and then captured the black isolated pawn, creating connected passers in the center. The endgame was slow, first Integral captured another pawn and then it pushed the center passers very carefully. Obsidian tried to counter by giving a pawn and creating a passer on the queen side but it was not strong enough, Integral queened and mated.

game 183, Leela - KomodoDragon: Leela pushed the pawn to b6 to complete the queen side diagonal block. KomodoDragon blocked the center and the pieces slowly moved to the king side. After move 30 the engines exchanged pawns on the king side and opened the f file, then all rooks were exchanged. Leela prepared its pieces and on move 57 sacrificed a knight for a pawn on the queen side and created a passer. After exchanging queens Leela sacrificed a bishop for a pawn and connected a second passer. KomodoDragon stopped one passer but Leela queened, resulting in a Q vs BB ending. KomodoDragon lost material quickly, Leela promoted another pawn and won.

game 185, Stockfish - Berserk: Stockfish blocked the center, then a pawn exchange created a passer in the center. Stockfish had a space advantage, all pieces moved to the queen side and eventually the engines opened the b file. Berserk captured a pawn and created a passer on the queen side, all rooks were exchanged and the game reached a QBB vs QBN position. When Stockfish was ready it exchanged queens, regained the pawn and pushed the passer to the 7th rank. Stockfish exchanged a pair of bishops and connected a second passer. Berserk gave up, it gave a pawn and allowed a queening, followed by mate.

game 190, Leela - Ethereal: Leela moved its king forward and then opened the e file. The engines exchanged a pair of rooks, and both white knights for black bishops. After exchanging queens the game reached a RBB vs RNN position, the white king walked to the queen side and the bishop pair threatened the black king. Leela managed to capture two pawns, creating connected passers facing the black king. Leela pushed the passers, trapping the black king, Ethereal gave a knight for one. Ethereal lost more material but couldn't get its king out of danger, mate followed.

game 192, Stockfish - KomodoDragon: The engines traded the two white knights for the two black bishops, KomodoDragon moved its king forward without castling. A pawn exchange on the king side exposed the black king. Stockfish pushed two pawns on the queen side, it gave one and opened files for its major pieces. After a series of exchanges the game reached a QRB vs QRN position, Stockfish captured a pawn and exchanged queens. Stockifsh captured a second pawn, it had a passer on both sides of the board. The white king moved to the queen side to support a passer, Stockfish gave the rook for a knight and KomodoDragon couldn't stop a queening followed by mate.

game 193, KomodoDragon - Berserk: KomodoDragon pushed pawns on the king side and castled long. In a series of exchanges Berserk gave a rook for a knight and pawn and exposed the white king. KomodoDragon created a passer on e6, Berserk castled late to develop its king side rook. Another series of exchanges reduced to a RB vs BB position, black with two pawns up. The engines traded pawns, eventually KomodoDragon had one pawn left, a passer on the queen side. KomodoDragon managed to capture black pawns until Berserk had only one left as well. KomodoDragon played the 8-man ending patiently, Berserk pushed its passer to the 2nd rank but couldn't promote. KomodoDragon pushed its passer slowly, eventually Berserk lost its passer and also a bishop for the white passer, mate followed.

game 196, Integral - Leela: Integral pushed pawns on the king side and castled long, Leela placed a knight on e4 and Integral exchanged it for a bishop. The game reached a QRR vs QRR position, after trading pawns the queens were exchanged and Integral captured a pawn. Leela pushed a passer forward while Integral moved its rooks to the 7th rank. Integral exchanged a pair of rooks and captured the black passer, then it managed to capture another pawn. The engines reduced to a 6-man rook ending which Integral won after 50 more moves.

Standings after RR7: Stockfish +14, Leela +10, Integral +7, Obsidian +3, PlentyChess -4,  Berserk -6, KomodoDragon -10, Ethereal -14. Stockfish had 3 wins in RR7, it extended its lead a little. Leela in second place also had 3 wins but one loss to Obsidian. Obsidian lost twice and dropped to 4th place, Integral had 3 wins and it is back to 3rd place. Despite beating Leela, Integral has a very small chance of qualifying to the superfinal with only one RR to go. KomodoDragon is closer to relegation after 3 losses and one win, compared to Berserk's 3 losses and 3 wins.

game 201, Obsidian - Berserk: The center was blocked, there were no exchanges after the start. A pawn exchange opened the f file, the king side was blocked and Berserk also blocked the queen side. Obsidian castled an exposed king on move 32, the engines shuffled for a long time and evals started to increase. On move 59 the first minor pieces were exchanged, then in a series of exchanges the engines reduced to a QR vs QBN position, white two pawns up with connected passers in the center. Berserk gave the bishop for the two passers, Obsidian captured a pawn and created another passer. Berserk delayed with checks but eventually it gave the queen for the rook and the passer, Obsidian queened again and mated. There were two white wins in this game pair. 

game 202, KomodoDragon - Ethereal: The center was blocked, KomodoDragon pushed pawns on the king side, it captured a pawn and created a passer on the h file. The white king moved without castling, Ethereal moved two minor pieces forward that made it difficult for the white pieces on the queen side. KomodoDragon managed to get its queen side rook to the king side, it gave back the pawn and moved its knights forward on the king side. When it was ready KomodoDragon captured a pawn and opened the g file, the passer moved to the 7th file with the black king trapped behind it. Ethereal exchanged pieces and lost material for the passer, the game reached a RN vs R position. KomodoDragon captured all black pawns, queened a passer and mated.

game 203, Stockfish - Integral: The center was blocked, Stockfish pushed pawns on the king side and moved its king without castling. The engines exchanged a pair of pawns and minor pieces on the king side, Stockfish kept a pawn on h6. The engines mostly shuffled for a while, all pieces moved to the king side and evals increased. On move 42 Stockfish pushed the f pawn, Integral gave a rook for a bishop and captured the pawn. The engines reduced to a RN vs NN position, Integral was a pawn up with connected passers on the king side but Stockfish blocked them. Stockfish created a passer in the center, it gave the rook for the black knights, queened and mated.

game 206, Leela - Stockfish: see featured game below.

game 212, Stockfish - PlentyChess: The engines blocked the center and queen side with diagonal pawn lines. Stockfish castled long, after a while it captured a pawn on the queen side and exchanged a pair of pawns on the king side. On move 31 the first minor pieces were exchanged, the engines shuffled for a while and evals increased. On move 46 the engines opened the f file, another minor piece exchange created a passer for PlentyChess. Stockfish gave the pawn back, then in a series of exchanges the engines reduced to a QRB vs QRB position. PlentyChess tried to attack the white king, Stockfish captured 3 pawns and created connected passers on the queen side. PlentyChess lost more material and was mated.

With 3 rounds Stockfish has a 4 point lead over Leela, it will win the division. Integral is still 1.5 points behind Leela after both lost to Stockfish, Integral also only drew against PlentyChess as white. KomodoDragon is only 1 point behind Berserk, still unlikely it can catch up but not impossible.

game 214, PlentyChess - KomodoDragon: The engines blocked the center, PlentyChess gave a pawn and opened the b file, giving KomodoDragon doubled passers. PlentyChess pushed pawns on the king side and blocked it as well except for the h file. After move 38 PlentyChess exchanged pawns and a pair of bishops on the king side, then moved its rooks first to the h file and then back to the a file. PlentyChess captured one of the black a pawns, KomodoDragon exchanged a pair of rooks. The white king moved to the center, KomodoDragon tried to defend both sides of the board, eventually PlentyChess attacked on the queen side. KomodoDragon gave a rook for a knight and the queen side opened, the game reached a RB vs NN position. PlentyChess captured pawns, KomodoDragon lost material and mate followed. 

game 215, Leela - Obsidian: There were no exchanges after the start, the engines moved their pawns slowly. Obsidian pushed pawns on the queen side, Leela attacked the center from the king side and exchanged a pair of pawns. Another pawn exchange opened the b file, Obsidian moved a rook forward and Leela blocked its path back. After a pawn exchange on the king side Leela created a passer and Obsidian created connected passers. Obsidian gave the trapped rook for a bishop and exchanged queens, the game reached a RRB vs RBN position. Obsidian lost a knight and there was a race between the passers, Obsidian was too busy defending to push its passers forward. The black passers were on the 3rd rank but Leela queened and mated first.

game 216, Integral - Ethereal: There were no exchanges after the start, the engines moved their pawns slowly and blocked the center. The engines shuffled for a while, Ethereal moved its rooks to the queen side but didn't push pawns. Evals increased slowly, Integral pushed pawns on the king side, the engines exchanged a pair of knights but there were no pawn exchanges. On move 41 the engines opened the g file, Integral pushed a passer to h6 and captured a pawn. After a series of exchanges the game reached a QRB vs QRN position, Integral captured another pawn and exchanged rooks. Integral gave the bishop but the black king was trapped, Ethereal lost material, Integral queened and mated. 

game 217, Integral - Berserk: The engines traded two white knights for two black bishops. The black queen moved forward on the queen side and Berserk captured a pawn. Berserk avoided pawn exchanges to keep the board closed and the white bishops less effective. A series of exchanges started on move 34, Berserk gave a rook for a bishop and pawns, the game reached a RB vs NN position. The engines captured all pawns except two each on the king side, Integral chased the knights away and captured the remaining black pawns. Berserk lost more material, Integral queened a passer and mated.

One round left, the gap between Leela and Integral is one point, the same as the gap between Berserk and KomodoDragon. In the last round Leela plays Integral and Berserk plays KomodoDragon, theoretically both can tie the scores. However in both games the bias is for the engine in front, so practically there is no chance of a tie. 

game 224, Leela - Integral: Leela pushed pawns on the king side, but it was Integral that chose to castle long. Evals jumped immediately when Leela castled short, Leela moved its rooks to the queen side, gave a pawn and opened the b file. In a series of exchanges the engines reduced to a RRN vs RBN position, Integral captured pawns until there were none left. Leela captured the bishop and started to hunt the black king. Integral lost more material and was mated. There were two white wins in this game pair. 

Featured game: Leela - Stockfish
game 206

Stockfish pushed pawns on the queen side and opened the a file. Then it pushed pawns on the king side, the engines opened the g file, Stockfish was a pawn up with a passer. Stockfish also had a bishop pair advantage and (negative) evals increased. 

The engines played out a long PV agreement. The engines exchaged queens, Leela captured a pawn and created a passer on the king side too. The engines reduced to a RNN vs RBB position, Stockfish traded a bishop for a knight which Leela didn't expect, Leela's eval dropped below 1. Stockfish captured a pawn, its eval continued to increase.

The engines seemed to shuffle for a long time, Leela's eval stayed low while Stockfish's eval jumped. After 20 moves Leela's eval started to increase again, Stockfish managed to trap the white king on the back rank and Leela exchanged rooks. Stockfish captured a pawn and created a second passer that Leela couldn't stop, Stockfish queened and mated.