Friday, October 7, 2022

Season 23 premier division, after RR4

Standings after RR4

In the second DRR the top3 engines beat the bottom5 by 14/15 game pairs, only SlowChess scored a draw against Stockfish. Both Stockfish and Leela beat KomodoDragon, they lead the table at the halfway point. KomodoDragon needs wins within the top3 if it wants to have a chance of getting to the superfinal this season. 

Within the bottom5 engines Ethereal and Stoofvlees have 3 game pair wins, with Ethereal beating Stoofvlees the only loss. Berserk and rofChade are last with two game pair losses each, they are the most likely candidates for relegation, though SlowChess is not too far ahead.

Interesting games

game 58, Ethereal - Stoofvlees: Ethereal was a pawn up, Stoofvlees pushed pawns on the queen side and created a passer. This also gave Ethereal a strong center with a pawn majority, evals started to increase. The black pieces surrounded the black king with a backward pawn on e7. Stoofvlees untangled itself by giving a bishop for the two central pawns, the engines reduced to a RB vs R position. Ethereal captured black pawns until Stoofvlees gave its rook in desperation, game over.

game 59, Stockfish - Berserk: The game started in the Dutch defense Leningrad variation, in a line played at the highest levels of human chess. Berserk deviated from known theory quickly, Stockfish pushed a pawn to c6 and Berserk tried to blockade with a pawn line. Berserk went a pawn up and opened the king side, then gave a rook for a bishop, it seemed to be holding for a long time. Stockfish's eval came down even after it gave a pawn and the c pawn became a passer on the 7th rank. On move 53 Berserk apparently blundered, Stockfish had less than 40 seconds on the clock when its eval jumped. Berserk expected the next move but regretted its move immediately. The engines reduced to a RR vs RN position, the white rooks dominated the board. Berserk captured the passer but it slowly lost material and the game ended in a tablebase win.

game 60, Leela - KomodoDragon: See featured game below. 

game 65, Ethereal - SlowChess: After pieces were developed the white queen moved forward to capture a pawn. A series of exchanges followed and only QR vs QR remained on move 34. The black king was more exposed, Ethereal managed to capture a second pawn and then reduce to a tablebase win.

game 66, Stockfish - rofChade: Stockfish was a pawn up from the start, evals started to increase after a few moves. rofChade gave a second pawn, I'm not sure why but it didn't expect Stockfish to capture it. Stockfish gradually exchanged pieces until only RN vs RB remained. rofChade got a pawn back, after some preparations Stockfish traded pawns and created connected passers in the center. rofChade gave a bishop for the passers, Stockfish captured all the black pawns and reduced to a tablebase win. 

game 67, Leela - Stoofvlees: There were many exchanges after the start, Leela went a pawn up but evals appeared to be drifting down. The game reached a RB vs RB position, on move 37 Leela's eval jumped. Stoofvlees thought it was ok for another 7 moves before it realized the advancing white pawns were dangerous. Leela pushed a passer to the 7th rank, Stoofvlees decided not to give a rook to stop it. Leela under-promoted to a rook, still strong enough to mate a few moves later.

game 68, KomodoDragon - Berserk: The engines traded R and two pawns for BN after the start, the black king walked to the king side and the white king castled long. Berserk tried to develop its king side rook through the h file, it offered a rook trade that KomodoDragon thought was a mistake. KomodoDragon reduced to a B vs pawns endgame, it captured black pawns and created an unstoppable passer to win.

game 69, SlowChess - Berserk: There were very few exchanges from the start, SlowChess pushed a pawn to a6. After move 30 a series of exchanges opened the king side and evals started to increase. SlowChess had a passer in the center that Berserk blocked, after more piece exchanges SlowChess moved  a rook forward and Berserk couldn't prevent it from creating a second advanced passer. Berserk lost a rook for a passer and mate followed.

game 74, Leela - Ethereal: There was one pawn exchange after the start, opening a file in the center. The engines exchanged pieces gradually, all rooks were exchanged through the open file, evals were stable for nearly 40 moves. On move 39 Ethereal blundered and allowed Leela to reduce to a knight ending, material was equal but Leela had a king side passer. Leela used zugzwang to capture a pawn, and it still had a passer. After a few pawn trades Leela gave the knight and deflected the black knight so it could queen the passer, game over.

game 75, KomodoDragon - rofChade: There were no exchanges and the engines built pawns walls from side to side. The queen side and center were locked, a pawn exchange opened the c file. Evals started to increase after the king side opened, both kings were exposed but KomodoDragon managed to walk its king to the center. KomodoDragon offered a rook for a bishop and rofChade refused to take, not wanting to create an advanced white passer. Instead KomodoDragon captured a rook for a bishop, then captured two pawns and reduced to a winning R vs B ending.

game 79, Ethereal - KomodoDragon: The game started with an 18-ply book in the French Steinitz Boleslavsky variation, played in human chess. KomodoDragon chose a line where it sacrifices a knight for two pawns and opens the queen side, still in theory. Evals increased steadily, KomodoDragon pushed pawns on the queen side and Ethereal blocked them with pieces. The engines opened a file on the king side and exchanged all rooks, only BNN vs BN remained. Evals were over 5 when Ethereal gave a pawn on the king side, KomodoDragon's eval dropped as it gave a knight for a pawn on the queen side. Despite having two extra pieces Ethereal needed two knights and a king to block 3 connected passers on the queen side, its bishop wasn't strong enough on its own. The engines shuffled until Ethereal realized it couldn't win.

game 81, Leela - SlowChess: Leela pushed pawns on the king side, SlowChess decided to castle long and evals started to increase. The black queen was out on the queen side and had problems getting back, Leela slowly increased the pressure on the queen side. SlowChess gave a pawn and a bishop, then continued to lose material until Leela mated.

game 84, Stoofvlees - rofChade: The white king moved without castling, there was only on pawn pair exchanged after the start. Stoofvlees pushed pawns on the king side and developed its rook through the h file, rofChade captured a pawn yet evals slowly increased. rofChade chose a sequence of moves that resulted in a QBB vs QR position on move 42. After exchanging queens there was a long period where Stoofvlees' eval did not change, there were only pawns in the center and Stoofvlees took time to plan. On move 90 Stoofvlees was ready and it pushed a pawn, the white king moved forward and on move 109 Stoofvlees captured a pawn and created a passer. The game ended in a tablebase win shortly after that.

Standings after RR3: Stockfish +8, Leela +7, KomodoDragon +4, Ethereal +1, Stoofvlees -2, SlowChess -5, Berserk -6, rofChade -7. Leela had a strong RR with a +4 score including a win against KomodoDragon. Stockfish only drew as white against SlowChess, its lead is only 0.5 points. KomodoDragon's loss puts it behind in 3rd place, it still has to face Stockfish as black in RR4. 

game 89, KomodoDragon - SlowChess: Evals started to increase a few moves after the start, a series of exchanges from move 20 resulted in a QB vs QB position on move 31. SlowChess was a pawn up but its king was in danger. The black king tried to hide behind a white pawn, SlowChess pushed a passer forward and the engines traded passers. The white king came forward, KomodoDragon went a pawn up and created passers on the queen side. After exchanging queens the passers became unstoppable, game over.

game 90, Leela - Berserk: Evals increased after the start, almost all pieces were on the queen side. After several exchanges Leela captured a rook for a knight and pawn. The game reached a RRN vs RBN position, both engines created passers which were then captured. Leela doubled rooks on the 6th rank and Berserk could not avoid losing material. The game ended in a tablebase win.

game 91, Stockfish - Stoofvlees: Stoofvlees castled short despite two white pawns advancing on the king side, evals increased quickly. Stockfish opened the king side and exposed the black king, after a series of exchanges the game reached a QB vs QB position with white a pawn up. The endgame was very slow, Stockfish's eval increased all the time but there seemed to be no progress with repeating moves. After 35 moves Stockfish managed to trade a pair of pawns, then it exchanged the bishops. Next Stockfish gave a pawn and created a passer, the game ended in a tablebase win not long after that.

game 92, Ethereal - rofChade: Ethereal opened the king side and created a passer, both engines castled long. All pieces were on the board until move 30, evals started to increase. There were several exchanges, Ethereal lost its passer and the game reached a QRR vs QRN position with black two pawns up. rofChade had two passers, Ethereal captured one quickly, after some shuffling and exchanging queens Ethereal captured the second passer. As always Ethereal took its time in a winning endgame, the game reached a tablebase win on move 104.

game 93, SlowChess - Ethereal: SlowChess pushed pawns on the king side, the white king moved forward without castling. SlowChess doubled rooks on the half open g file, Ethereal had a bishop that guarded g7. Ethereal tried to attack on the queen side, it gave a rook for a bishop but the pressure continued. The game reached a RRN vs RBB position, SlowChess created connected passers in the center. Ethereal couldn't stop a queening, game over. There were two white wins in this game pair. 

game 97, Berserk - SlowChess: Evals slowly increased, Berserk had a better pawn structure and both the black bishops were passive surrounding the black king. After some shuffling the engines exchanged a pair of rooks and only QRB vs QRB remained. The black king was exposed, using threats Berserk captured pawns until there were none left, mate was unavoidable.

game 98, KomodoDragon - Stoofvlees: On move 14 evals jumped, Stoofvlees didn't notice it trapped its own bishop ahead of its pawns. In a series of exchanges Stoofvlees saved the bishop and even went a pawn up, but now KomodoDragon forced the black king to move without castling. KomodoDragon attacked and soon the black king was in a mating net.

game 99, Leela - rofChade: The engines castled in opposite directions and evals started to increase. Leela went a pawn up and a series of exchanges left a QRR vs QRR position. rofChade had a passer in the center, it tried to protect it but eventually Leela captured it. After exchanging queens Leela pushed connected passers on the king side, rofChade lost a rook and the game ended in a tablebase win. 

game 100, Stockfish - Ethereal: After the start both engines played behind the pawn lines, both engines castled long. Only a few pawns were exchanged and the c file was open. All pieces were on the board until move 30, after the board cleared a little Stockfish doubled rook and queen on the c file and evals started to increase. Stockfish captured a pawn and then reduced to a N vs B ending. It took Stockfish more than 30 moves to convert the win.

game 104, Stoofvlees - Berserk: Stoofvlees pushed pawns on the queen side, Berserk castled short and Stoofvlees moved its king forward without castling. Stoofvlees attacked through the queen side, it traded BN for R and a pawn and created an advanced passer. Berserk gave a rook for two pawns to capture the passer, the white king was exposed to attacks by the black queen. Stoofvlees gave a rook for a bishop and forced a queen exchange, reducing to a winning R vs N ending two pawns up.

game 105, Stoofvlees - SlowChess: The center was blocked, both engines did not castle their kings. Stoofvlees walked with its king to the king side, developing a rook through the h file. SlowChess opened the b file and kept its king in the center. After move 22 evals started to increase, Stoofvlees gave a pawn on the king side and used a black pawn as a shield. After a series of exchanges the engines reduced to a BN vs BN position, Stoofvlees went a pawn up and it had two advanced passers, while SlowChess had one and less advanced. SlowChess lost both its pieces for the passers, the game ended in a tablebase win. 

game 107, KomodoDragon - Ethereal: Ethereal gave a knight for two pawns and pushed pawns on the queen side, following the reverse game 79 for 13 plys after book. Evals increased steadily, KomodoDragon blocked the black queen side pawns, and unlike the reverse game the major pieces stayed on the board. Ethereal gave a rook for a knight and captured white pawns until none were left. KomodoDragon placed both rooks on the back rank, Ethereal delayed with checks but after exchanging queens it was a rook down for two pawns. The game ended in a tablebase win.

game 110, Stockfish - KomodoDragon: Evals started to increase after move 13, Stockfish moved a rook forward with a tempo by attacking the black queen. After exchanging queens PVs mostly agreed, the engines exchanged pieces until only RN vs RB remained with white two pawns up. Stockfish had two passers but it was patient, after 30 moves KomodoDragon gave the bishop to capture one passer. The game ended in mate 15 moves later.

game 111, Ethereal - Berserk: Ethereal pushed pawns on the king side and was close to trapping a black bishop, its eval increased from the start. The center opened and both kings walked away without castling. After exchanging queens Berserk was two pawns up but the white rooks were much more active in the open files. The engines exchanged pieces and the game reached a RB vs RN position. Ethereal got a pawn back and created connected passers on the king side, Berserk captured the passers but lost its knight. Ethereal captured all the remaining black pawns, the game continued for almost 50 moves before ending in a tablebase win.

Featured game: Leela - KomodoDragon
game 60

The game started with a 4-ply book in the Dutch defense 1. d4 f5 2.g3 g6. The engines quickly left known theory, Leela pushed a pawn to h6 and despite this KomodoDragon castled short. Leela opened the center, went a pawn up and castled long. KomodoDragon sacrificed a knight, it felt confident it had a strong attack on the white king. 

Leela thought this was a mistake and its eval jumped immediately. The game followed KomodoDragon's PV exactly but its eval jumped as if it was surprised. The attack on the white king was not effective though KomodoDragon gained back material. Leela threatened the black king on the long diagonal, KomodoDragon exchanged pieces and the game reached a BBN vs RB position. 

KomodoDragon had connected passers on the queen side but Leela's bishops stopped their advance. KomodoDragon in desperation gave both its pieces for two pawns and created connected passers on the king side as well. 

Leela was able to queen a pawn first, KomodoDragon deflected the white bishop and pushed the h pawn but it was stopped on the 2nd rank. The game ended in a tablebase win


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