Season 29 lower leagues overview

I'm going through the games archive and looking at the results.

Entrance league

relegated from season 28 league 2: Velvet Igel Arasan Horsie 
played in season 28 entrance league: BlackMarlin DeepSjeng Clover Patricia Renegade 
new to TCEC (played in Swiss tournament): Torch Pawnocchio Quanticade Tarnished Heimdall 
returning to TCEC: Winter (season 26 entrance league) Halogen (season 27 entrance league)

Final standings

Torch won easily with 15 game pair wins. Tarnished finished in second place, not expected considering its low ELO, but this is may be because it is new to TCEC and there are not enough games for an accurate ELO calculation. Tarnished lost to Torch and Horsie, had 11 game pair wins and 2 draws. Five engines were in the race for the remaining 4 qualification spots. Halogen and Quanticade finished in joint 3rd place, though Halogen won the direct minimatch. For Halogen this was a small improvement compared to its last TCEC appearance in season 27. Pawnocchio, Horsie and Clover were tied in 5th place and continued to a 3-way tiebreak. Pawnocchio was a clear winner in the tiebreak, but Horsie and Clover were again tied and played a second tiebreak, which Clover won. Of the five new engines only Heimdall failed to advance to League 2.

Pawnocchio crashed twice in the league, in both games the position seemed to be drawn. Hopefully this will get fixed in the next stages.

Arasan and Igel, both appearing many times in TCEC, failed to qualify - perhaps approaching retirement.

League 2

The 6 qualifiers joined
relegated from season 28 league 1: Seer rofChade Stoofvlees
played in season 28 league 2:  Booot Ginkgo Uralochka 

Final standings

Torch won the league easily, with 15/22 game pair wins and no losses. Pawnocchio and Halogen finished in second and third places, with 2 game pair losses each. The 4th qualifier was Clover with 4 game pair lossses, ahead of Quanticade and Ginkgo that had 4 or fewer losses but less wins than Clover. All 4 qualifiers started in the entrance league, two of them newcomers to TCEC. 

At the bottom of the league were rofChade, Seer and Stoofvlees. These engines were members of the premier division in the past, but are on their way down and will have to play in the entrance league next season.

Pawnocchio was updated and had no crashes in the league. Tarnished performed worse when compared to the other qualifiers from the entrance league. It too was updated, perhaps this update was not an improvement. 

League 1

The 4 qualifiers joined
relegated from season 28 premier division: KomodoDragon Ethereal
played in season 28 league 1: Reckless Caissa Stormphrax Ceres Viridithas RubiChess

Final standings

Reckless won the league with 13/22 game pair wins and no losses. Torch was second with 9 game pair wins and no losses. Both engines advance to the Premier division. This is the second TCEC season for Reckless, last season it finished 3rd in league 1, this season it improved enough to advance. Torch is new to TCEC, it managed to reach the premier division in its first TCEC season like Integral last season (and Stoofvlees many seasons ago).   

Ceres finished in 3rd place, its first appearance in TCEC was in season 27 and it reached exactly the same place then, it still hasn't been able to advance further. Pawnocchio ended its first TCEC season in 4th place, after starting in the entrance league. Halogen also had a successful run this season after missing season 28, this is its best TCEC result.

KomodoDragon and RubiChess are still strong enough for league 1, both appeared in the premier division. KomodoDragon was a top engine for a long time, but apparently it is not developed further. Ethereal was also a long time premier division engine, its developer is focused on Torch and Ethereal seems to be dropping quickly. 

Season 29, taking a break

Season 29 leagues in TCEC have started, but I have no time to go over the games. I am still looking at the games occasionally, and I may write a post now and then, but I'm too busy for covering this season in full. Not sure when I will have time to return to this.

So, I hope the season is exciting and I will try to enjoy it as a spectator. 

Season 28 superfinal games 91-100, season summary

Stockfish is the winner of the season 28 superfinal. The final score is 36-21 with 43 draws. In the last 10 games Leela managed one last game pair win, and Stockfish won two to extend its lead to +15. This gap is similar to the previous two seasons. 

Stockfish dominated the superfinal from the start, it won 3 game pairs of the first 5, and 5 pairs of the first 10, while Leela had no game pair wins. Leela won its first pair in the 11th pair played but Stockfish extended its lead to +8 after 20 game pairs. Leela won a second pair but then in game 43 Leela lost on time after a long shuffle in a drawn position, probably a bug in time management. As a result Stockfish won the pair form both sides, an event that hasn't occured in a superfinal for a long time. At the half way point Stockfish had a +9 lead, close to a gap record breaking pace. In the second half Stockfish slowed down, it continued to increase the lead but breaking a gap record was no longer possible. Leela won 3 more pairs in the match and the final gap was +15. 

lower leagues

premier division

personal

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Games 91-92 started with a sideline in the Old Benoni variation. In game 91 there were no exchanges after the start, the engines blocked the center and queen side. On move 25 the engines exchanged pawns and a pair of bishops, evals slowly increased. The engines shuffled and exchanged a pair of rooks, on move 56 the queens were exchanged and evals increased again, but the shuffling resumed and evals drifted down. On move 103 Leela opened the h file and Stockfish's eval dropped. The engines continued to shuffle, Leela didn't lower its eval and the game ended in a 50 move draw.

In game 92 again there were no exchanges after the start, the engines blocked the center bur not the queen side. There was a pawn exchange on the king side and then several minor pieces were exchanged as well, evals started to increase. Stockfish opened the h file while Leela captured a rook for a knight. On move 41 the game reached a QRB vs QRR position, with a white passer in the center.

Stockfish pushed the passer to the 7th rank, the white queen moved forward and the black king walked to the queen side. Stockfish exchanged queens and captured all the black pawns on the queen side. Leela lost material but couldn't stop the white passers. Stockfish queened and mated. Stockfish wins the game pair, it leads 34-19.

Games 93-94 started with a sideline in the French defense, normal variation. In game 93 the engines blocked files on the queen side, the white queen moved forward on the king side and threatened the black king. The engines exchanged pawns and minor pieces on the king side, then exchanged pawns on the queen side and both engines created a passer there.

The engines mostly shuffled for a while though evals increased. A minor piece in the center opened the e file and gave Leela a bishop pair advantage. Leela pushed pawns on the king side, after exchanging a pair of rooks Stockfish gave the passer, perhaps to free the square for its queen.

The black rook moved forward but nothing came out of it. Stockfish gave another pawn on the king side and weakened the white pawn structure, a pawn exchange exposed the black king completely. Leela pushed passers forward, after exchanging queens Leela moved 3 pawns facing the black king and mated.

In game 94 the engines exchanged minor pieces and opened the c file. Stockfish gave a bishop for 3 pawns and exposed the black king, evals started to come down. Leela surrounded its king with pieces, Stockfish captured another pawn and created a passer. The engines exchanged a pair of knights, Leela captured the passer and lost another pawn, the game reached a QR vs QRN position. Both queens moved around the board, after a while the engines exchanged queens. Stockfish pushed its passers, Leela exchanged rooks and captured one passer. The black bishop managed to stop the white passers, evals were low and the game was adjudicated. Leela wins the game pair, Stockfish leads 34-20.

Games 95-96 started with a line in the Caro-Kann advance variation. In game 95 a minor piece exchange opened the f file, Stockfish gave a rook for a bishop and castled long. The engines exchanged a pair of rooks, Stockfish's eval came down. After a pawn exchange on the queen side the engines started to shuffle with a few pawn moves. The game ended on move 102 by a 50 move draw. In game 96 Leela castled long though the f file remained closed. Stockfish moved its king without castling, it pushed pawns on both sides. There was a series of exchanges, the engines opened files on the king side and exchanged a pair of rooks. After the other pair of rooks was exchanged the game reached a QBB vs QBN position. Stockfish created a passer in the center and exchanged queens. Leela blocked the passer and the engines shuffled for a long time. Evals came down and the engines exchanged pawns before the game was adjudicated.

Games 97-98 started with a sideline in the French Winawer, advance variation. The center was blocked and white had doubled c pawns. In game 97 the engines exchanged pawns on the king side and Stockfish castled long. Leela kept its king in the center and moved the queen forward on the queen side. Leela connected its rooks, Stockfish created a passer on the king side and the engines exchanged a pair of rooks. After a pawn exchange on the queen side Stockfish created a second passer and slowly pushed it forward. The white king walked to the king side, Leela moved a rook forward and captured the black passer on the king side. 

Leela kept an eye on the black passer, it switched queen and rook so that the rook blocked the passer and the queen moved forward. Stockfish shifted defenders to the king side and the white queen returned to the queen side. On move 78 Leela captured the black passer, then rooks were exchanged and the game reached a QBN vs QBN position.

Leela was two pawns up but with no passers, it forced a knight exchange and created a passer on the f file. The white king moved forward in the center, Stockfish gave a pawn to block the king and this connected a second white passer. Leela captured two more pawns, Stockfish lost the bishop and after exchanging queens Leela queened a passer and mated. 

In game 98 Stockfish pushed pawns on the king side and Leela castled long, Stockfish kept its king in the center and developed the rook through the h file. After some shuffling the engines exchanged a pair of knights and the white queen moved forward on the king side. Evals increased as the engines opened the king side and reduced to a RRB vs RRB position.

Stockfish moved a rook to the 7th rank, so that the black bishop and king could not get out of their corner. After some shuffling the white king moved to the queen side and then forward to the center. Leela used one rook to keep the white king away from the e pawn, but then Stockfish managed to capture the black f pawn. After exchanging a pair of rooks Stockfish pushed the g passer forward. Leela captured the passer and then in a series of exchanges Stockfish reduced to a king and pawns ending two pawns up. Stockfish queened twice and mated. There were two white wins in this game pair, Stockfish leads 35-21.

Games 99-100 started with a 20 ply sideline of the KID Averbach variation. The center was blocked and the engines castled in opposite directions. In game 99 Leela pushed pawns on the king side, after a minor piece exchange the h pawn became a passer. The engines blocked the center, Leela pushed the passer to h7 and the black king hid behind it. The engines shuffled for a long time and evals came down, there was a minor piece exchange and the shuffling resumed. After move 70 there were more piece exchanges, Leela gave the passer and reduced to a RB vs RB position. The game was adjudicated when evals were low enough.

In game 100 Stockfish pushed pawns on the king side and exchanged minor pieces, but didn't push the h pawn beyond h4. Leela pushed pawns on the queen side and prepared an attack, Stockfish's eval increased while Leela thought it was safe. Leela gave a pawn to open the queen side, it concentrated all its major pieces there. Stockfish seemed to ignore the danger to its king. 

Leela realized it was in trouble but couldn't stop the attack now. In a long PV agreement Leela exchanged the e2 bishop and captured the b5 pawn. Leela couldn't open the b file, instead it gave a pawn and created a passer for each engine. Leela gave the bishop for two pawns to expose the white king, despite 3 major pieces on the b file it only managed a piece exchange and the game reached a QN vs Q position. Leela had 2 passers, it pushed one to the 7th rank and there Stockfish captured it while Leela captured the white passer. The black attack ended, Leela captured a pawn on the king side and Stockfish got the initiative. 

The endgame was slow, Stockfish kept its pawns safe and protected its king from checks, it managed to move the knight forward protected by a pawn. The white king captured the a pawn, this exposed it to checks but Stockfish managed to get its 3 pieces forward at the expense of the g pawn. Stockfish managed to push its last pawn forward, after exchanging queens Stockfish queened and mated. Stockfish wins the game pair, the final score is 36-21.

Season 28 superfinal game 81-90

After 90 games Stockfish leads 33-19 with 38 draws. Leela won a game pair after 12 pairs with no wins and 3 losses. However Stockfish won three pairs in a row and extended its lead to +14 with 5 pairs remaining. 

Games 81-82 started with a rare sideline in the Pirc defense. In game 81 the engines exchanged pawns and a pair of bishops in the center, then exchanged queens. Evals increased slowly, the engines formed pawns lines and exchanged a pair of knights, creating a passer for Leela. Stockfish captured a pawn and created doubled passers in the center. Leela reduced to a RRB vs RRN position, regained the pawn and created a passer on the queen side. 

Leela moved a rook forward and protected the a passer with the bishop. It captured two pawns and pushed the a passer forward. Stockfish started to lose material, Leela queened and mated.

In game 82 there was one pawn exchange in the center, the engines played behind their pawn lines. On move 25 the engines started to play out a long PV agreement, there were many piece and pawn exchanges and evals came down. The game reached a QB vs RRB position, both engines with two pawns which are connected passers. Stockfish pushed the passers and Leela lost the bishop to capture them. Leela wouldn't lower its eval, after a long shuffle the engines reduced to a 6-man position and the game was adjudicated a few moves later. Leela wins the game pair, Stockfish leads by 29-18.

Games 83-84 started with a rare sideline in the King's Gambit declined, Falkbeer countergambit. White started with a pawn up. In game 83 the black queen moved forward on the king side. Stockfish regained the pawn, Leela gave a rook for a knight and created a passer in the center. Stockfish captured the passer and exchanged queens, the exchanges continued and the game reached a RB vs RR position on move 29, white a pawn up.

Evals stayed stable for a while, on move 38 the engines traded pawns on the king side and each created a passer there. Stockfish's (negative) eval started to increase though the engines seemed to shuffle and Stockfish's clock was under one minute. After a pawn exchange on the queen side Stockfish managed to push its passer safely to the 4th rank. Leela's (negative) eval remained below 1.

Leela's eval started to react, the black king circled around the f passer until it got to h4. Leela preferred to exchange rooks and keep its passer. Both engines pushed their passers, Leela lost its bishop and both engines queened. Leela delayed with checks as long as it could, Stockfish forced a queen exchange and mated.

In game 84 the engines repeated the reverse game for 64 plys (!!), with the same RB vs RR position on move 29 and the same pawn trade on the king side, though Leela let Stockfish take first and Stockfish took with the bishop and not the rook. Leela had the same problem of moving its king forward to support the f passer. Stockfish didn't wait and pushed its h passer forward, after a pawn exchange on the queen side Leela captured the white passer. Leela's (negative) eval increased when it decided to push the a pawn on move 66.

Stockfish tried to avoid the exchange and pushed the b pawn, but a few moves later the engines traded the pawns anyway. Leela played the 8-man position very slowly, with checks and pins while Stockfish avoids exchanges. After move 110 Leela managed to push the passer, Stockfish captured a rook but couldn't stop the queening followed by mate. There were two black wins in this game pair, Stockfish leads 30-19.

Games 85-86 started with a rare sideline in the KID normal variation. The center was blocked, all pieces were on the board and the c file was open. In game 85 Leela pushed pawns on the queen side, Stockfish pushed a pawn on the king side and opened the f file. The white king was stuck in the center, after exchanging queens Leela moved the queen to the king side and Stockfish doubled rooks on the f file. Evals came down and in a series of exchanges the engines traded a bishop and a knight for a rook and pawns. There was a long shuffle and the engines reduced to a RB vs BBN position. Stockfish captured pawns and allowed Leela to push a passer, then gave a bishop for the passer. The game was adjudicated in a RB vs BN ending when evals were low enough.

In game 86 Stockfish castled its king, then pushed pawns on the queen side. Leela captured a pawn and created a passer on the queen side, but evals increased steadily. Stockfish blocked the black passer, in a series of exchanges on the king side the engines traded a rook for a bishop and knight, and the g file opened. 

Stockfish captured a pawn and the d pawn became a passer. In a series of exchanges the engines equalized material and reduced to a QBN vs QBN position. After exchanging queens Leela pushed its passer while Stockfish captured a blocking knight. Both engines queened, Leela tried to delay but it lost material and was mated. Stockfish wins the game pair, it leads 31-19.

Games 87-88 started with a rare sidelline in the Sicilian, Scheveningen variation. In game 87 the engines developed their pieces, then exchanged a few minor pieces and evals came down. Stockfish moved a rook forward in the center and invited an exchange with a minor piece but Leela refused. After exchanging a pair of rooks Stockfish forced a rook for bishop exchange, the game reached a RN vs BN position. After some shuffling the knights were exchanged, Leela's eval was low enough and the game was adjudicated. 

In game 88 the engines repeated the reverse game for 17 plys up to transpositions. The engines mostly shuffled for a while, on move 30 a pawn trade opened the e file and created a white passer in the center. The engines played out a long PV agreement with many exchanges, Leela's eval drifted down. Stockfish started with giving a rook for a bishop, Leela captured the passer and then gave the material back. In a QRB vs QRN position Leela gave the queen for the rook and bishop.

Leela's eval was low for a long time, Stockfish pushed the c pawn to c5 and started to shuffle. On move 70 Leela's eval started to react, Stockfish moved the king forward on the king side, Leela captured the c passer and Stockfish captured a pawn on the king side. Stockfish pushed the h pawn and by move 91 it managed to capture the remaining black pawns on the king side. 

Stockfish saw the win in its PV but it was still a long way. It took 20 moves to start pushing the g passer forward, eventually Stockfish gave the queen for the knight and queened. It took another 25 moves to win the 6-man Q vs R ending. Stockfish wins the game pair, it leads 32-19.

Games 89-90 started with a sideline in the Owen defense. In game 89 the engines exchanged pawns and minor pieces, Stockfish pushed a pawn on the queen side and opened the b file. Leela captured a pawn and created a passer on the queen side, Stockfish's eval came down. Stockfish regained the pawn, the engines reduced to a QB vs QB position. After a long shuffle Stockfish captured a pawn on the king side, the queens were exchanged and the game was adjudicated after Leela's eval came down.

In game 90 the engines exchanged pawns and minor pieces, Leela did not open a file on the queen side and it kept its king in the center. Evals increased slowly, the engines exchanged queens and Leela created a passer in the center. The game reached a RRB vs RRB position on move 31.

Stockfish exchanged a pair of rooks and captured the black passer. The engines exchanged pawns on the king side and Stockfish created a passer there. Stockfish kept the black king away from the king side while its king moved forward. After some shuffling Stockfish pushed the a pawn forward, on move 81 it managed to capture the black h pawn with its king and connected a second passer.

Stockfish gave back a passer but then threatened mate on the h file. Leela lost material, Stockfish queened and mated. Stockfish wins the game pair, it leads 33-19.

Season 28 superfinal games 71-80

After 80 games Stockfish leads 29-17 with 34 draws. Stockfish won a game pair and there were 4 drawn pairs, 3 of which had two white wins. The gap is +12 with 10 game pairs left.

Games 71-72 started with a sideline in the KID orthodox variation. All pieces and pawns were on the board and the center was blocked. In game 71 there was a series of exchanges after the start, Leela captured a pawn and exposed the black king. Stockfish pushed a pawn to f3 trapping the white king in the corner. Evals came down, the engines opened the b file and shuffled for a while, then exchanged a pair of rooks and reduced to a QRN vs QRB position. After a long shuffle Stockfish traded its queen for a rook and bishop, Leela's eval was low enough and the game was adjudicated.

In game 72 there were no exchanges after the start, the engines played behind their pawn lines and evals stayed above 1. After move 34 evals started to increase, the engines exchanged minor pieces on move 47. On move 57 Stockfish exchanged the first pawns and opened the h file, it captured a pawn and the exchanges continued until only RBN vs RNN were left. 

The white rook moved to the 7th rank behind the black pawns, Leela tried to protect its pawns. Stockfish created a passer on the king side and the white king moved forward. Leela lost a knight for the passer, Stockfish captured a pawn and reduced to a knight vs pawns ending. Stockfish queened a passer and mated. Stockfish wins the game pair, it leads 26-14.

Games 73-74 started with a sideline in the Slav defense. In game 73 the engines exchanged minor pieces on the king side and opened the b file. Evals stayed under 1, the engines exchanged all rooks and both engines had a passer on the queen side. After move 33 Leela's eval started to increase, it pushed pawns on the king side and blocked it. The engines reduced to a QBN vs QBN position, Leela captured a pawn and created a second passer.

Stockfish gave a pawn and attacked with its queen, capturing back a pawn. Stockfish didn't want to exchange queens, it lost a knight instead. Leela attacked the black king and Stockfish lost material, followed by mate.

In game 74 the engines blocked the center and the queen side, there was one minor piece exchange. Stockfish created a passer in the center through a pawn exchange, Leela blocked with a knight. The engines mostly shuffled for a while, Stockfish's eval increased first and then Leela's eval increased as well. After move 53 Stockfish opened the king side and sacrificed a rook to attack the black king.

All white pieces participated in the attack, Stockfish gave the second rook for a knight while Leela pushed the passer forward in a weak counter. Stockfish captured the passer and then won back material, in a series of exchanges the engines reduced to an opposite color bishops ending with white a pawn up. 

Stockfish captured the c pawn and created a second passer, then used the bishop and king to drive the black king away and captured the d pawn as well. Leela couldn't avoid a queening and mate. There were two white wins in this game, Stockfish leads 27-15.

Games 75-76 started with a rare sideline in the Indian defense, knights variation. In game 75 evals were low after the start, the engines exchanged a few minor pieces, then a pawn exchange gave Leela a passer on the queen side. Evals jumped when Leela managed to push the passer safely, protected by a knight. Stockfish gave a rook for a knight to capture the passer. 

Leela moved a rook forward and captured two pawns. Stockfish decided not take the rook for a bishop, it tried to keep its defending pieces and to keep the king side closed. Leela pushed the g pawn and opened the g file while Stockfish created connected passers. The black king was in danger, Leela created a passer in the center and pushed it forward as well. After queens were exchanged Stockfish lost more material and was mated.

In game 76 the engines repeated the reverse game for 13 plys up to transpositions, after that there were pawn and minor piece exchanges, the engines opened the b file. Leela blocked the file with a bishop, Stockfish exchanged bishops and captured a pawn, creating a passer in a QRR vs QRR position. 

Stockfish gave the pawn back on the king side and weakened the black pawn structure there. The engines exchanged all rooks, Stockfish regained the pawn while the black king tried to protect the pawns around it. Leela captured the white passer and equalized material but evals were high. 

The black queen was far from the king side, Stockfish used checks to capture a pawn and create a passer in the center. Stockfish captured a second pawn and created a passer on the king side, by then the black queen could give checks on an exposed white king but Leela couldn't avoid a queening and mate. There were two white wins in this game, Stockfish leads 28-16.

Games 77-78 started with a rare sideline in the Sicilian opening. In game 77 the engines blocked the center, Stockfish pushed pawns on the queen side and Leela blocked it too. Evals came down, in a series of exchanges Leela traded a rook and a pawn for two minor pieces, it created a passer in the center and the h file opened. Stockfish castled its king and avoided exchanges on the king side, on move 39 the queens were exchanged and the engines started to shuffle. Evals were low but there were too many pieces for the draw rule, the game ended in a 50 move draw. In game 78 the engines blocked the center and queen side as before. Stockfish gave a knight for a pawn and created a passer in the center, its eval jumped. Then Leela gave a bishop for a pawn, Stockfish still had the passer but evals decreased. Leela castled long and its eval remained calm, it captured the white passer while the white queen moved forward on the king side and captured two pawns there. In a series of exchanges Leela gave a knight and the game reached a QBN vs QB position, the white king was exposed and Leela started a series of checks. Stockfish's eval jumped up and down, Leela captured the white bishop and let Stockfish take control. Stockfish captured a pawn and created a passer, it gave a series of checks until it was Leela's turn again. Leela captured a pawn and created a passer as well. Eventually Stockfish's eval came down as well, the game was adjudicated on move 121.

Games 79-80 started with a rare sideline in the Benoni defense, the center was blocked and all pieces and pawns were on the board. In game 79 Stockfish pushed pawns on the king side and Leela pushed pawns on the queen side. The engines opened the b file, a pawn exchange on the king side exposed the black king. Evals slowly increased, Leela moved a rook forward and took control of the b file. Stockfish created a passer in the center, on move 36 the engines exchanged a pair of bishops, the first pieces to be exchanged. 

After some shuffling the engines opened the g file and exchanged a pair of rooks, closing the g file and opening the h file. The white queen threatened the king side on the long diagonal. Stockfish traded its queen and a pawn for a rook and a knight, creating connected white passers on the king side. 

The white queen moved forward and the game reached a QN vs RNN position. Leela blocked the black passer, Stockfish tried to force the blocking knight to move but was not strong enough. Leela captured all the black pawns on the queen side, when the black rook moved forward Leela moved its knight forward and attacked. The black king was left with a weak defense, the black passer was not fast enough and Leela mated.

In game 80 the engines blocked the queen side, Leela pushed the h pawn and opened the h file. Evals increased steadily, Stockfish moved a rook to the h file and there were a few more pawn exchanges. Stockfish created a passer on the king side and Leela created one in the center, on move 32 the first minor pieces were exchanged, Stockfish doubled rooks on the h file and the engines exchanged a pair of rooks. 

Stockfish moved a knight forward on the king side, Leela exchanged it with a bishop and both passers were captured. Stockfish attacked with 3 pieces, it tried to find the right configuration and on move 56 it doubled queen and rook on the h file.

Leela chose to counter with an attack on the white king. The black queen moved forward and gave checks until Stockfish blocked with the knight. Stockfish resumed its attack, Leela lost material and was mated. There were two white wins in this game, Stockfish leads 29-17.

Season 28 superfinal games 61-70

After 70 games Stockfish leads 25-14 with 31 draws. Stockfish won one game pair of the last 5, there were 3 double draws and one draw with two white wins. Stockfish is still increasing its lead but slowly, after a gap of +9 at the half way point the gap increased by +2 in the last 10 game pairs. With 15 game pairs left it is reasonable that the final gap will be in double digits but not a record.

Games 61-62 started with a line in the Blumenfeld countergambit, Duz-Khotimirsky variation, played in high level human games. In game 61 Stockfish moved the king without castling, it captured a pawn in the center but its queen side pieces were late developing. Evals came down, in a series of exchanges Leela captured a rook for a bishop and the white king was exposed. The engines reduced to a RR vs RB position with black two pawns up. The engines exchanged a pair of rooks, both had an advanced passer that couldn't advance. Leela's eval came down and the game was adjudicated. In game 62 the engines repeated the reverse game for 39 plys. The engines continued to exchange pieces until only R vs B remained. Leela was a pawn up and evals were low, Leela created two passers before the game was adjudicated.

Games 63-64 started with a rare sideline in the Caro-Kann two knights variation, the white queen was out on the king side. In game 63 the engines blocked the center, Stockfish pushed pawns on the queen side and Leela pushed the h pawn. The black queen moved forward on the queen side, the engines opened the b file and Stockfish's eval dropped to 0. In a series of exchanges Leela gave a knight for pawns and opened the king side, then the engines reduced to a RB vs RNN position. Leela had connected passers in the center, but its eval also came down. Leela pushed the passers and Stockfish gave a knight to stop them. The game reached a drawn rook ending, when Leela's eval was low enough the game was adjudicated.

In game 64 the engines repeated the reverse game for 13 plys, and when Leela diverged Stockfish's eval jumped. The engines opened the b file and Leela concentrated most pieces on the queen side. Stockfish exchanged minor pieces and then attacked the king side with a queen and knight. More exchanges reduced to a QRN vs QRB position on move 40.

Leela pushed its c pawn and Stockfish blocked with the rook, then Leela captured the rook with its bishop. This allowed Stockfish to attack the black king while the black pieces were too far to help. Stockfish chased the black king, it captured the black queen for a knight, then the white queen managed to capture the remaining black pieces with mate following. Stockfish wins the game pair, it leads 24-13.

Games 65-66 started with a rare line in the Benoni gambit. There was one pawn exchange and most pieces were on their starting square. In game 65 the engines developed pieces and castled, after exchanging pawns and a pair of knights Leela had a passer in the center and the c file was open. In a very long PV agreement Stockfish pushed pawns on the king side, the engines exchanged minors and a pair of rooks. The a file opened and Leela moved a rook forward.

The engines shuffled, Stockfish's eval slowly increased while Leela's eval stayed under 1. On move 64 Leela's eval jumped, 5 moves later the engines exchanged minors. Leela gave a rook for a knight and connected a second passer in a QB vs QR position. 

Stockfish pushed pawns on the king side and gave two pawns, I'm not sure why, perhaps it was low on time and perhaps it thought it was losing anyway. Leela now had two pairs of connected passers, it pushed the king side passers forward. Stockfish gave the queen and the rook (again, why??) and mate followed.

In game 66 the engines repeated the reverse game for 13 plys. Evals started to increase early, the engines exchanged minor pieces and then Stockfish pushed pawns on the king side with one pawn getting to f6. Stockfish created a passer after a pawn exchange on the queen side, for a few moves Stockfish offered a knight and Leela refused to take, fearing a dangerous attack on the black king. In a series of exchanges the engines reduced to a QBN vs QBN position with white a pawn up. 

Leela traded bishops and exposed the white king to checks, in a pawn trade the white h pawn became a passer. Stockfish forced a queen exchange and Leela couldn't stop a queening. Stockfish queened a second pawn and mated. There were two white wins in this game pair, Stockfish leads 25-14.

Games 67-68 started with a line in the Sicilian Najdorf, Amsterdam variation. In game 67 there were no exchanges after the start, Leela castled long while Stockfish moved its king to the king side. The engines opened the h file, Stockfish pushed pawns on the queen side and evals decreased. The engines exchanged a pair of bishops and opened the c file, then exchanged more minor pieces. After all rooks were exchanged the game was adjudicated. In game 68 the engines repeated the reverse game for 21 plys up to transpositions, Stockfish castled long and Leela moved its king to the king side. The engines opened the h file, Stockfish blocked the black queen side pawns with knights. A minor piece exchange opened the d file, Leela captured a pawn on the king side while Stockfish cleared the black queen side pawns and created connected passers. The engines mostly shuffled for a while and evals came down. Leela captured a pawn and Stockfish ended the game in a check repetition. 

Games 69-70 started with a line in the Old Indian defense, Czech variation. The black queen moved forward on the queen side. In game 69 the engines castled in opposite directions, a pawn exchange opened the d file and evals came down. The engines exchanged minor pieces and a pair of rooks, the black queen moved forward and threatened the white king. After some shuffling the engines exchanged queens, the game was adjudicated after another minor piece exchange. In game 70 both engines castled short, exchanges opened files on the queen side and evals came down. The engines continued to exchange pieces and pawns, the queen side pawns were cleared and Stockfish moved a rook forward. Stockfish captured 3 pawns and Leela captured a knight, the game reached a RN vs RBN position. Leela gave the bishop for passer on the 7th rank, the game was adjudicated a few moves later.

Season 28 superfinal games 51-60

After 60 games Stockfish leads 23-13 with 24 draws. Leela won its third game pair, but Stockfish won twice. Stockfish's lead is now +10, its win rate is slowing and it will be harder to break the record gap. There is no doubt as to the winner of the match, even though there are still 20 pairs yet to play. 

Games 51-52 started with a sideline of the Czech Benoni defense. In game 51 the engines opened the a file, exchanged a pair of rooks and Leela captured a pawn. After some shuffling the remaining rooks were exchanged, the game reached a BN vs BN position on move 43. Stockfish's eval dropped, the engines exchanged minor piecs and Leela used a bishop to block black passers. The engines traded pawns and opened the board, each pushed a passer but was blocked before the promotion square. There was a long shuffle, the game was adjudicated on move 129 close to the 50-move draw. 

In game 52 the center was blocked, there was one pawn exchange on the queen side and one on the king side. Stockfish kept its king uncastled, evals were stable and the engines shuffled. The white king walked to the king side, after move 50 evals increased very slowly. On move 66 Leela pushed a pawn on the queen side and Stockfish pushed one on the king side, preparing to open the board.

Both engines were low on time, Stockfish ignored the queen side and attacked the king side while Leela captured the two white bishops. Stockfish exposed the black king and created 3 passers. The engines exchanged queens and the game reached a R vs BBN position, white 3 pawns up.

Stockfish managed to trap and capture the knight. Leela captured two pawns but still had to face 3 passers, Stockfish queened twice and mated. Stockfish wins the game pair, it leads 21-11.

Games 53-54 started with a 30-ply line in the Ruy Lopez, Chigorin defense. The center was closed and all pieces and pawns were on the board. In game 53 Stockfish gave a pawn to open a path for a bishop. Leela opened the a and h files, then the engines exchanged a pair of bishops and all rooks. The engines shuffled for a while and then the exchanges continued, the game reached a BN vs BN position on move 59. Stockfish's eval was at 0, Leela took a long time to lower its eval. The engines exchanged bishops and shuffed, the game was adjudicated on move 100. In game 54 there were no exchanges after the start, evals started to decrease. The engines opened the h file and Leela captured a pawn. A pawn exchange opened the c file and the engines shuffled for a while. On move 52 the first pieces were exchanged, Stockfish traded a rook for two minor pieces. The game reached a R vs BN position and was adjudicated.

Games 55-56 started with a sideline in the French Winawer, advance variation. The center was blocked and the white queen moved forward on the king side. In game 55 Stockfish pushed a pawn on the king side to harass the white queen, Leela exchanged pawns on the queen side and opened the b file. The black king stayed in the center, in a series of exchanges Stockfish gave a knight for two pawns and the queens were exchanged. 

Stockfish moved a rook forward and the black king walked to the king side, Leela defended the c2 pawn and then gave back a knight for pawns. It captured another pawn and the c pawn became a passer. Leela continued to keep its c pawn safe, the white king slowly moved forward in the center. A series of exchanges reduced to a RN vs RN position. 

Leela pushed the passer with the king supporting in front of it, Stockfish gave the knight to capture the passer. Leela captured a pawn to create another passer, Stockfish couldn't prevent a queening and mate followed. 

In game 56 there were no pawn exchanges after the start, the engines exchanged all bishops and Leela castled long. The engines shuffled behind their pawn lines, on move 62 there was a pawn exchange on the queen side. The shuffling resumed and on move 107 the engines exchanged a pair of knights. After the engines exchanged queens evals came down, Leela gave a knight for two pawns and after a pair of rooks was exchanged the game was adjudicated. Leela wins the game pair, Stockfish leads 21-12

Games 57-58 started with a 20-ply rare sideline in the KID fianchetto, classical variation. The center was blocked and all pieces and pawns were on the board. In game 57 Leela pushed pawns on the queen side, Stockfish pushed the h pawn to h3. The engines opened the b file and then opened the f file, Stockfish captured a pawn in the center. Leela captured the black h pawn, then in a long PV agreement Stockfish gave a rook for a knight, the engines exchanged pieces until only QR vs QN were left. Stockfish was two pawns up with 3 passers, its eval was 0. Leela captured one passer and its eval came down, the game was adjudicated.

In game 58 the engines exchanged a pair of minor pieces on the queen side, the files remained closed. The engines shuffled for a while, on move 43 Stockfish's eval jumped. Stockfish gave a pawn on the queen side, the a file opened but Stockfish doubled rooks on the b file. After another minor piece exchange Stockfish regained the pawn, the white b pawn became a passer. In a series of exchanges the engines reduced to a RBN vs RBN position. 

Leela had to watch the white b pawn, Stockfish moved the rook to the 7th rank and then captured the black c pawn. Leela managed to capture the white passer but lost its bishop. Stockfish captured the remaining black pawns, it had one pawn left and Leela couldn't stop the queening and mate. Stockfish wins the game pair, it leads 22-12.

Games 59-60 started with a line in the Alekhine defense, modern variation. In game 59 the engines played out a long PV agreement, one pair of bishops was exchanged and Stockfish had an isolated pawn in the center. The white queen moved forward and the engines exchanged queens and minor pieces, Leela also had an isolated pawn in the center. Evals slowly increased, on move 33 the game reached a RNN vs RBN position.

Both kings moved to the center, Stockfish blocked the white king moving forward on the queen side. The engines exchanged pawns on the queen side, Leela captured a pawn and created a passer. The engines exchanged minor pieces, Leela abandoned the passer and captured a pawn on the king side. 

Leela captured a second pawn and created a passer. The white king moved forward and captured the last black pawn. Leela pushed passers forward and queened, Stockfish lost material and was mated. 

In game 60 the engines played out a different long PV agreement, the engines exchanged queens and a pair of knights and the black king moved without castling. Evals jumped after Stockfish opened the center, on move 27 the game reached a RBB vs RBN posoition. 

Both rooks moved forward, both engines captured a pawn on the queen side. The white king moved forward and captured the two black pawns on the king side that had no support. 

Leela captured one pawn back but Stockfish still had a passer on the king side. Leela captured a pawn on the queen side but Stockfish moved the rook to the 7th rank and its king was in front of the white passer. Leela gave the knight for the passer, Stockfish trapped the black king in the corner and mated. There were two white wins in this game pair, Stockfish leads 23-13.