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.

Season 28 superfinal games 41-50

After 50 games Stockfish leads 20-11 with 19 draws. Leela won (only) its second game pair of the match, but then it lost a game on time for the second time and Stockfish won a game pair from both sides - something we haven't seen in a superfinal for a long time. The other 3 game pairs were drawn and Stockfish extends its lead to +9 at the halfway point. At this rate the final score gap may be close to record high for a superfinal.

Games 41-42 started with a sideline of the Nimzo-Indian defense, St. Petersburg variation. In game 41 there were no exchanges after the start, the engines formed pawn lines and moved pieces behind them. The center and queen side were blocked, Stockfish had a bishop in front of the pawns. On move 29 there was a pawn exchange on the king side, after move 39 there were a few minor piece exchanges. Leela's eval was close to 2 at some point but then started to drift down as the engines shuffled. On move 82 there was another minor piece exchange, Stockfish moved its king to the queen side and Leela moved its king to the center. After move 112 evals started to increase, the black forward bishop was trapped (though safe) and Leela managed to exchange queens and capture a pawn, creating a passer.

The black bishop was out of the game, Leela moved its rooks to the king side and its bishop forward, then pushed the g pawn. Stockfish exchanged pawns and captured the passer, but after a pair of rooks was exchanged Leela moved its rook to the 7th rank, attacking the black pawns. Leela captured two pawns and Stockfish couldn't prevent a queening. Stockfish delayed with checks but was eventually mated.

In game 42 the engines blocked the center and queen side, similar to the reverse game. There were no pawn exchanges and Leela kept its bishops behind the pawns, on move 30 the engines exchanged a pair of bishops. The engines blocked the king side as well and started shuffling. On move 62 there was a pawn exchange, Stockfish's eval increase for a while and came back down when the shuffle continued. Stockfish had one pawn move left, the game ended in a 50 move draw on move 150. Leela wins the game pair, Stockfish leads 16-9.

Games 43-44 started with a rare sideline of the English, Anglo-Indian defense, the black queen moved forward in the center. In game 43 Leela pushed pawns in the center and moved its queen forward on the queen side. After Stockfish castled Leela pushed a pawn to h6, Stockfish captured a pawn on the queen side and created a passer for both engines. Stockfish pushed its passer, Leela captured a pawn and moved its queen forward. At first Stockfish avoided exchanging queens, but after Leela captured the black passer the queens were exchanged. The engines reduced to a RRN vs RRN position, Stockfish regained the pawn and the engines started to shuffle. Stockfish's eval was 0, Leela's eval slowly drifted down. On move 85 Leela pushed the passer and reset the 50-move counter, but then it failed to move on time and lost.

In game 44 Stockfish thought Leela castled too soon, both evals jumped as Stockfish exchanged pawns and opened the h file. The white king stayed in the center and Stockfish doubled queen and rook on the h file. Leela tried to threaten the white king, in a series of exchanges the engines reduced to a QR vs QB position with black a pawn up.

Stockfish moved its pieces to the center and its king to the king side. The rook moved to the back rank and pinned the black bishop. Leela tried to delay with checks, it avoided exchanging queens. Eventually Stockfish captured the bishop and mate followed. Stockfish wins this game pair from both sides, it leads 18-9.

Games 45-46 started with a rare sideline in the Scandinavian defense. In game 45 there were no exchanges after the start, Stockfish was late developing its queen side. Leela pushed a pawn on the king side, after exchanging a pair of knights the engines opened the g file. In a long PV agreement the center pawns were cleared, most pieces were exchanged and the game reached a RB vs BN position with black two pawns up.

For a while it seemed Leela was not sure how to proceed and evals remained stable. When Leela moved the rook to the back rank Stockfish's eval started to increase. Leela managed to trap the black king on the h file and its eval also increased. Eventually the rook moved to the h file, the black knight and king moved away and Leela captured the h pawn on move 71.

Stockfish tried to counter Leela's passer by pushing its own passer to the 2nd rank. Leela blocked with its king and threatened to take the a7 pawn, even by sacrificing its rook, since its a pawn would be unstoppable. Stockfish couldn't take the passer, the black king moved away from the king side and Leela slowly captured more pawns. Stockfish lost more material, Leela queened a passer and mated.

In game 46 Leela developed its queen side pieces quickly, the engines exchanged minor pieces and a pair of pawns in the center and opened the d file. Evals increased steadily, Stockfish gave a pawn on the king side while Leela moved a rook forward on the queen side. Stockfish captured pawns on the queen side and created connected passers.

Leela moved its queen back to stop the white passers, Stockfish exchanged knights and moved its queen forward through the center. Leela captured one passer but now its king was in danger, it exchanged pieces and reduced to a rook ending with white a pawn up. 

Stockfish had two passers, while Leela defended the white king captured the remaining black pawns. Stockfish then queened twice and mated. There were two wins in this game pair, Stockfish leads 19-10.

Games 47-48 started with a rare sideline of the Sicilian Najdorf, Zagreb variation. In game 47 the engines exchanged minor pieces and Stockfish moved its queen forward. Leela captured a pawn, opened the a file and exchanged a pair of rooks. Stockfish castled late and Leela kept its king in the center. Leela captured another pawn and created connected passers on the queen side. The game reached a QRB vs QRB position, Stockfish's eval dropped despite being two pawns down. The engines traded pawns, Stockfish blocked the white passers and Leela didn't find a way to improve. After exchanging queens Leela's eval dropped and the game was adjudicated. In game 48 the black queen stayed back, Stockfish pushed pawns on the queen side, opened files and created a passer. The black king moved to the king side without castling, Leela gave a rook for a knight and pawn and the game reached a QRR vs QRB position. Leela had passers in the center, Stockfish abandoned its passer and captured the two black passers. Leela's eval dropped as queens and more pawns were exchanged, Leela found a fortress, from move 51 it repeated rook moves while Stockfish shuffled. The game was adjudicated on move 99.

Games 49-50 started with a sideline in the Pirc defense. In game 49 the engines exchanged a pair of knights in the center, Leela moved a bishop to c6 and evals increased. Leela captured a pawn on the queen side and Stockfish gave a rook for the forward bishop and a pawn.

Leela opened the a file, doubled rooks there and moved a rook forward. Stockfish tried to keep the center and king side closed and to defend the open queen side. There was a pawn exchange on the king side, and Leela pushed a pawn forward on the queen side and created a passer. Then Leela captured another pawn in the center.

Leela captured pawns and opened files on the king side, threatening the black king. Stockfish lost more and more material and was mated. 

In game 50 the engines exchanged minor pieces, then exchanged pawns in the center and Leela captured a pawn. Leela tried to hold on to its extra pawn and it didn't develop its queen side pieces. Stockfish's eval increased while Leela's eval decreased until it realized it was in trouble after a 17 minute think on move 20. 

Leela moved its knight while Stockfish captured the e pawn and defended its passer, offering its bishop for several moves. Leela gave a rook for a knight in the center, Stockfish pushed the passer and Leela captured the bishop. Stockfish moved a rook to the 7th rank, then gave a pawn and opened the g file. Stockfish pushed the passer to the 7th rank and threatened the black king, in a series of exchanges Leela captured the passer and the game reached a Q vs RB position.

The engines traded pawns until there was only one white pawn and two black. Stockfish used checks and fork threats to push its pawn to the 7th rank, Leela gave the bishop to capture the passer. Stockfish converted the 6-man ending in 30 more moves. There were two wins in this game pair, Stockfish leads 20-11.

Season 28 superfinal games 31-40

After 40 games Stockfish leads 16-8 with 16 draws. There were 4 drawn game pairs in the last 5, one double draw and 3 double white wins. Stockfish managed one game pair win and it extended its lead to +8. Leela still has only one game pair win after 20 pairs. 

Games 31-32 started with a rare sideline of the Bird opening. In game 31 the engines blocked the center, Leela pushed pawns on the king side and both engines castled long. Leela placed a bishop on d6, then exchanged it for a knight, a pawn exchange opened the g file. Stockfish tried to attack the white king but was not effective. Leela doubled rooks on the g file, captured a pawn and created a passer.

Stockfish tried to block the white passer, Leela moved a rook to g7 and offered it for a bishop but Stockfish refuse because that would connect a second passer. Instead Leela gave a knight for a pawn to create connected passers. Stockfish tried to give a bishop for one of the passers, eventually Leela captured the bishop and kept the passers, though they became doubled.

In a QRN vs QRN position Leela captured another pawn and queened a passer, then it sacrificed a queen and mated with the other.

In game 32 Stockfish gave a pawn before blocking the center, both engines kept their kings in the center uncastled. The engines exchanged minor pieces and Leela captured a second pawn, evals remained low. Stockfish doubled queen and rook on the f file and threatened the black king, then it captured a pawn creating a passer in the center and forcing Leela to move its king, trapping the king side rook. Evals started to increase, Leela created a passer on the king side. Stockfish traded its passer for a pawn on the king side, then the game reached a RRN vs RRN position.

Leela was a pawn up but Stockfish had a rook on the 7th rank. The engines traded pawns, then exchanged a pair of rooks and Stockfish captured the black passer. After some shuffling Stockfish managed to capture another pawn and created two passers on the queen side.

Stockfish pushed a passer forward, it wanted to exchange knights but Leela gave its knight for free to avoid a 7-man position. This was only a small delay, Stockfish queened and mated. There were two white wins in this game pair, Stockfish leads 13-6.

Games 33-34 started with a sideline of the Caro-Kann defense, two knights attack. In game 33 there were no exchanges after the start, Leela pushed a pawn on the queen side all the way to a6. There was a minor piece exchange followed by some shuffling, evals drifted down. Another minor piece exchange opened the d file, the engines exchanged all rooks and reduced to a QB vs QB position. The engines traded pawns and created passers, but evals were low enough for adjudication.

In game 34 both queens moved forward early and after a minor piece exchange Leela grabbed a pawn in the center. The d file opened and the black king was in the center. In a long PV agreement most pieces were exchanged and the game reached a Q vs RB position with black a pawn up on move 27. Stockfish's eval was low, but after it created a passer on the king side its eval started to jump. Leela's eval dropped below 1.

Stockfish slowly pushed the passer while the black pieces threatened its king. Leela managed to capture the passer but the white queen got behind the black pawns. Stockfish equalized the number of pawns, it still had to work hard with its queen to be able to capture another pawn and create a passer. Leela's eval slowly increased but was still around 1.

Stockfish was very patient, the white king moved forward before Stockfish tried to push the passer. It took nearly 50 moves to force a pawn exchange and create a second passer, Leela captured one but was then mated. Stockfish wins the game pair, it leads 14-6.

Games 35-36 started with a line in the Bogo-Indian, Gruenfeld variation played in high level human chess. There were no exchanges and the center was blocked. In game 35 there was a pawn exchange on the queen side. The engines moved their major pieces to the queen side and shuffled for a while with evals stable. There were a few minor piece exchanges and evals increased a little. Then all the major pieces were exchanged and the game reached a BB vs BN position with white a pawn up.

Stockfish's eval increased faster than Leela's. The engines exchanged a few pawns, Leela captured a second pawn and created a passer. There was another pawn trade in the center and Leela added two more passers. 

Leela pushed its passers forward, Stockfish lost material, Leela queened and mated.

In game 36 there were no exchanges after the start, Stockfish kept its king uncastled. Evals remained stable as the engines mostly shuffled behind their pawn lines, the white king walked to the queen side. Stockfish thought that Leela's move 35 was a mistake, its eval jumped and Leela's eval jumped immediately too. Stockfish exchanged a pair of pawns and created a small opening on the king side. 

Leela moved the bishop to d4, Stockfish pushed the e pawn forward and captured on d6, creating a doubled passer. The engines started to exchange pieces and pawns, Leela captured a passer but lost a rook for a bishop. Leela managed to captured the second passer, Stockfish gave back the material and captured a knight. The game reached a QN vs Q position, Stockfish saw the win in its PV.

Stockfish pushed the b pawn forward and Leela couldn't stop it. After exchanging queens Stockfish queened and mated. There were two white wins in this game pair, Stockfish leads 15-7.

Games 37-38 started with a rare sideline in the KID Petrosian variation. In game 37 the engines exchanged a pair of pawns that opened the c file and blocked the center. Leela pushed pawns on the king side and kept its king in the center. Evals came down as the engines exchanged minor pieces and queens. The engines traded pawns and kept exchanging pieces until only RN vs RN were left, and the game was adjudicated. In game 38 the c file stayed closed, the engines blocked the center and most of the king side, Leela completed the king side pawn line with a bishop. The engines shuffled and Stockfish castled long, evals dropped to 0. After exchanging a pair of bishops Stockfish attacked the king side while Leela captured pawns on the queen side. The engines exchanged pieces until only QN vs QR remained and the game was adjudicated.

Games 39-40 started with a rare sideline of the Kangaroo defense. In game 39 after exchanging a pair of knights Leela castled long. Stockfish opened the c file and evals slowly increased. Leela blocked the center, Stockfish pushed pawns on the king side and exchanged a pair. Leela moved a rook forward, the engines exchanged all minor pieces and Leela captured a pawn. 

Leela moved its king forward on the queen side, the engines exchanged queens and Leela pushed the e pawn forward to the 7th rank. Leela exchanged a pair of rooks and captured almost all the black pawns, it then queened a passer and mated.

In game 40 Stockfish castled long as in the reverse. There was one pawn exchange in the center but files remained closed, evals increased steadily. Leela moved a pawn to b3 after a minor piece exchange, Stockfish doubled rooks on the d file and prepared a pawn advance.

Leela captured a pawn while Stockfish pushed the d pawn and it became a passer on d6. After some shuffling the engines exchanged queens, Stockfish gave a rook for a bishop and then won back a rook for the passer. The game reached a RN vs R position and each engine had a passer. 

Both engines queened a passer, Leela was first and it gave a few checks and captured a pawn. Then Stockfish attacked and the queen and knight were very effective together. Stockfish captured the black queen and mated. There were two white wins in this game pair, Stockfish leads 16-8.