Season 28 superfinal games 21-30

After 30 games Stockfish leads 12-5 with 13 draws. Leela won its first game pair of the match, but then lost 3 of the next 4 pairs. Stockfish increased its lead to +7 despite the loss. Leela lost a game on time, very unexpected.

Games 21-22 started with an 18-ply sideline of the KID orthodox variation. In game 21 the engines exchanged a pair of pawns in the center and pushed pawns on the queen side, then they opened the b file. Leela captured a pawn and created a passer, the engines exchanged a pair of rooks and evals increased. In a long PV agreement Leela pushed the passer forward and exchanged minor pieces, Stockfish created a passer in the center.

Stockfish pushed pawns on the king side, Leela avoided opening files there. Leela moved pieces forward, the black king was threatened. Leela gave a rook for a knight and a pawn, creating two more passers. 

Stockfish gave the passer, it lost more and more material until its king was exposed, mate followed.

In game 22 the engines opened the c file and kept the center closed, then mostly shuffled behind their pawn lines. By move 36 the pawn lines blocked the whole board except the open c file. The white king walked to the queen side and the shuffle continued for close to 50 moves. On move 80 evals suddenly jumped, Stockfish sacrificed a knight and created connected passers on the queen side. Leela also created passers there, a series of exchanges reduced to a QBB vs QBN position and evals came back down. The engines shuffled until exchanging queens, then the game was adjudicated. Leela wins the game pair, Stockfish leads 8-4.

Games 23-24 started with a 20-ply sideline of the Pirc defense. In game 23 Stockfish pushed pawns on the king side, then a long series of exchanges cleared the queen side pawns and Leela was a pawn up. Stockfish blocked the king side, the game reached a QRN vs QRB position and evals came down as the engines shuffled. The engines exchanged rooks on move 49, exchanged a few pawns after move 73 and the game was finally adjudicated on move 130.

In game 24 Leela exchanged a pair of pawns on the queen side, Stockfish gave a rook for a bishop and its eval increased. Leela was weak on the dark squares, it traded a knight for the white DS bishop, then Stockfish created a passer and captured a pawn. Stockfish thought Leela's move 23 was a mistake and its eval jumped, Leela agreed after a 20 minute think. Leela gave back the material and captured the white passer, Stockfish cleared the black pawns on the queen side and reduced to a queen ending with a pawn up.

Stockfish used checks to push the passer forward, Leela captured it on the 7th rank but lost a pawn on the king side. Stockfish saw the win in its PV, it captured another pawn and reduced to a 6-man tablebase win. Stockfish wins the game pair, it leads 9-4.

Games 25-26 started with a sideline in the English 4 knights variation. In game 25 the engines pushed pawns without exchanges, there were a few minor piece exchanges. Leela moved a bishop forward, the first pawn exchange on move 29 opened the a file and Leela moved a rook forward. Stockfish exchanged the forward bishop, a knight exchange blocked the center and reduced to a QRR vs QRR position. Evals came down, the engines exchanged a pair of rooks and Stockfish moved its pieces to the king side. Leela tried to open the king side, when it captured a pawn Stockfish moved a rook forward and gave checks. Stockfish gave the rook and Leela avoided a stalemate, giving time for the black queen to force perpetual check. In game 26 Stockfish exchanged minor pieces and castled long. The engines opened the d file, Leela moved its major pieces to the queen side and Stockfish exchanged a pair of rooks. Evals drifted down as the engines mostly shuffled, Stockfish captured a pawn and opened the a file. On move 69 the remaining rooks were exchanged, then on move 81 Leela failed to move in time and lost with evals close to 0. Stockfish wins the game pair, it leads 10-4.

Games 27-28 started with an 18-ply rare sideline in the Sicilian Najdorf variation, white castled long and the black king was still in the center. In game 27 Stockfish grabbed an early pawn on the king side, evals increased steadily from the start. The engines exchanged minor pieces on the king side and Stockfish created a passer. On move 28 Stockfish finally castled its king, despite having weak pawn support.

Leela captured the d6 pawn and moved a knight forward to f6, Stockfish gave a rook for the knight. Leela cleared the black queen side pawns and Stockfish cleared the white king side pawns so both engines had 3 passers. Each engine lost one passer and queens were exchanged, resulting in a RRN vs RBN position.

Leela pushed the passers forward and Stockfish defended with its rook and knight. Leela drove the black knight away, Stockfish gave material and tried a desperate passer run. Leela lost a rook for the passer, then queened and mated.

In game 28 the engines repeated the reverse game for 11 plys and Leela was up a pawn. Leela then decided to castle long, evals again increased steadily. Stockfish had a space advantage, for a few moves it could take a knight but refused so as to avoid a trapped bishop. When the black knight moved Stockfish exchanged bishops. In a long PV agreement Stockfish traded a rook for two minor pieces and created a passer on the king side. Leela had connected passers supported by rooks. 

Stockfish blocked the black passers and Leela managed to protect them but couldn't push them forward. The white passer became a threat and Leela moved rooks to block it. Stockfish then shifted major pieces to the open g file. Leela captured a pawn on the queen side while Stockfish moved a rook to the back rank and exchanged a pair of rooks. The game reached a QNN vs QR position, Stockfish saw the win in its PV.

Stockfish gave a pawn and started to chase the black king with just the queen and one knight. The black pieces couldn't help, Stockfish captured the black queen, queened a passer and mated. There were two white wins in this game pair, Stockfish leads 11-5.

Games 29-30 started with a rare sideline of the French defense, the c file was open. In game 29 there were no exchanges after the start, on move 20 a pawn exchange opened the f file. The engines blocked the center, in a series of exchanges all rooks were gone and then the engines reduced to a BN vs BN position. Stockfish's eval was close to 0 but Leela played on, the engines blocked the queen side and Leela's eval slowly decreased. The game was adjudicated on move 113.

In game 30 there were no exchanges after the start, Stockfish's eval started to increase and on move 19 there was a series of exchanges in the center. The engines exchanged a pair of rooks and Leela's eval also started to increase, Stockfish captured a pawn and opened the d file. After exchanging queens the game reached a RB vs RN position.

The black king moved forward, Leela captured a pawn on the queen side and Stockfish moved the rook forward. The black king moved back and was trapped on the back rank, Stockfish exchanged the minor pieces and reduced to a rook ending two pawns up. The engines exchanged a pair of pawns, Stockfish won the 6-man position after 40 more moves. Stockfish wins the game pair, it leads 12-5.

Season 28 superfinal games 11-20

After 20 games Stockfish leads 8-3 with 9 draws. Leela won two games and Stockfish won the reverse games twice. Then Stockfish won two game pairs and increased its lead to 5. Leela has no game pair win in the first 10 pairs.

Games 11-12 started with a sideline of the French Tarrasch, closed variation. In game 11 the center was blocked and the engines opened the c file. The engines shuffled and all pieces were on the board until move 30, Leela's eval slowly increased. In a series of exchanges of minor pieces Leela captured a pawn and created a passer on the queen side. The engines exchanged a pair of rooks, then continued to shuffle and Leela's eval drifted back to around 1. After move 50 Leela's eval increased again, it pushed the g pawn forward. 

The black queen was stuck on the king side, Leela exchanged pawns on the queen side and opened the b file. Stockfish regained the pawn and created a passer in the center while Leela moved its queen forward. The engines exchanged pieces and reduced to a BN vs BN position, Leela created a second passer.  

Leela exchanged minor pieces, Stockfish captured one passer but the white king moved forward on the king side and created more passers there. Leela queened one and mated.

In game 12 the engines repeated the reverse game for 23 plys with a transposition, the center was blocked and the c file was open. Stockfish pushed pawns on the king side and evals started to increase. Leela gave a pawn on the queen side, then a series of exchanges opened the board and gave Stockfish a passer in the center. Stockfish captured another pawn and created doubled passers on the queen side, Leela captured one of these passers. The black queen moved forward on the king side, Stockfish moved a rook forward on the queen side.

The white king was exposed and Stockfish had to be careful. After exchanging a pair of rooks the white queen moved forward. Stockfish abandoned its knight, it captured the black rook while Leela captured 3 white pawns.

Stockfish saw the win in its PV, it gave checks and pushed the passers forward, careful to avoid perpetual check on the other side. Eventually Stockfish exchanged queens, queened the passer and mated. There were two white wins in this game pair, Stockfish leads 5-2.

Games 13-14 started with a rare sideline of the Wade defense. In game 13 there was on minor piece exchange after the start. The engines slowly formed pawn lines without exchanges, Leela moved its king to the king side without castling, evals stayed mostly stable around 1. After move 26 there was a series of exchanges, the engines opened the board and reduced to a QRN vs QRN position.

Leela moved a rook forward on the queen side, captured a pawn and created a passer. In a long PV agreement Stockfish moved a rook forward behind the white passer, strangely Stockfish's eval increased while Leela' eval drifted down. Stockfish moved the queen forward as well and captured the white passer, then it gave a rook for a knight and pawn and created a passer. Leela exchanged queens and cleared all the queen side pawns. 

Stockfish saw the loss but it took 15 moves for Leela's eval to show a win. Stockfish gave a pawn and couldn't stop the white king advancing forward. Leela captured the remaining black pawns, it kept one last pawn, queened and mated.

In game 14 Stockfish moved its king without castling and Leela kept its king in the center. Stockfish's eval started to increase early, there was a pawn trade on the queen side, then the engines opened the g file. After a bishop exchange Stockfish captured a pawn and created a passer on the king side. It gave a knight and pushed the passer to the 7th rank, supported by two rooks. The white queen moved forward, in a series of exchanges Leela captured the passer and lost material, the game reached a Q vs RN position. 

Leela tried to hold the center, the white king slowly moved forward on the queen side. Eventually Stockfish cleared the black pawns on the queen side and created a passer. It gave the queen for a rook to queen the passer, mate followed. There were two white wins in this game pair, Stockfish leads 6-3.

Games 15-16 started with a rare sideline of the Indian defense, London system. In game 15 the engines exchanged most minor pieces in the center, Leela kept its king uncastled in the center. Stockfish pushed pawns on the queen side while Leela walked its king to the king side and freed the king side rook. The engines opened the d file and exchanged a pair of rooks, the exchanges continued and the game reached a queen ending. Leela was a pawn up, Stockfish's eval was at 0 but Leela continued to shuffle and trade pawns. The game was adjudicated on move 138 after Leela lowered its eval.

In game 16 Leela pushed pawns on the queen side, Stockfish kept its king in the center. After a few minor piece exchanges in the center Stockfish captured a pawn, then the engines reduced to a QRN vs QRB position. In a long PV agreement Stockfish created a passer on the queen side and captured another pawn. Both queens moved forward, Stockfish captured a third pawn but Leela regained two pawns before reducing to a queen ending on move 47.

Evals remained more or less stable for a long time, it seemed Stockfish was looking for the right sequence of moves. The white king moved all the way to the back rank, with the black queen chasing. Then the white king walked to support the passer, Stockfish gave a pawn and managed to push its passer forward after 40 moves. The passer was on the 7th rank and still Leela's eval was below 1. Leela's eval finally reacted, on move 122 it lost the queen for the passer and mate followed. Stockfish wins the game pair, it leads 7-3.

Games 17-18 started with a rare sideline of the Blumenfeld countergambit, white was a pawn up. In game 17 the engines opened the queen side and Leela created a passer there. The engines stablized their pawn lines and exchanged minor pieces, on move 42 the queens were exchanged and the engines started to shuffle. Evals slowly drifted down, Leela moved a pawn on move 54 and then on move 94. On move 130 the engines started to exchange pawns and pieces opening the board. Stockfish regained the pawn and evals were close to 0, the game was adjudicated on move 157 when enough pieces have been exchanged.

In game 18 the queen side stayed closed, Leela pushed the c pawn forward and Stockfish's eval increased. Leela gave two knights and attacked the white king. In a long PV agreement Leela captured a rook and a pawn, creating connected passers in the center.

The black passers looked dangerous but both evals were high. Leela exposed the white king, Stockfish captured one of the passers after exchanging a pair of rooks. Stockfish exposed the black king and captured the second black passer, then chased the black king. Leela lost material and was mated. Stockfish wins the game pair, it leads 8-3.

Games 19-20 started with a rare sideline of the Italian two knights defense, Traxler counterattack. White was a pawn up but its queen side was undeveloped, Black moved its king without castling. In game 19 there was a long PV agreement after the start, Leela developed its pieces and the engines exchanged minor pieces and queens. Evals started to decrease, the game reached a RRN vs RRB position and the engines started to shuffle. The engines exchanged minors and a few pawns, the game was adjudicated when evals were low enough. In game 20 the engines exchanged bishops and opened the f file. After some shuffling the engines opened the queen side. On move 51 a pair of rooks was exchanged, on move 67 there was a pawn exchange, on move 98 the game reached a QRN vs QRB position. Evals were close to 0, Leela gave the bishop and a pawn and threatened mate on the back rank, Stockfish secured a draw with perpetual check.

Season 28 superfinal games 1-10

After 10 games Stockfish leads 4-1 with 5 draws. There were two white wins in the first game pair, of the next 4 game pairs Stockfish won 3 and one was a pair of draws. Before the start of the superfinal Leela had a score of 1-1 in game pair wins against Stockfish, but after 5 more pairs played in the suprfinal the score is 4-1 in favor of Stockfish, with 4 draws. Which is a better preictor of the superfinal result?

The opening book was created by Jeroen Noomen, with computational help from Windfishballad and Kittenkaboodle. Details can be found here.

Games 1-2 started with a sideline of the Owen defense. In game 1 there were no exchanges after the start, Stockfish had problems with piece development and Leela gained space. There was one minor piece exchange and Stockfish castled long, evals were high and stable for a while. It seemed that Stockfish was trying to hold the pawn line, but evals started to increase, Leela doubled rooks on the a file and opened it on move 38.

A minor piece exchange created a white passer on a5, Stockfish tried to open the king side with a pawn exchange but Leela kept it defended. Stockfish gave a pawn to activate its light square bishop, Leela opened the e file and moved a rook forward. Stockfish captured a pawn on the queen side while Leela captured two and created two passers on the king side. On move 66 the engines exchanged queens.

Leela pushed the king side passers forward and Stockfish couldn't stop them. A few pieces were exchanged, then Leela queened and mated.

In game 2 there were many exchanges after the start, Leela gave a pawn and castled long. The engines played out a long PV agreement, the black queen moved forward on the king side, Leela gave another pawn and opened the f file. Stockfish captured a third pawn on the queen side and exposed the black king, Leela regained one pawn and exchanged queens and a pair of rooks, resulting in a RBN vs RBN position with white two pawns up.

Stockfish moved a rook forward, Leela captured a pawn and created a passer in the center. Then in a series of exchanges the engines reduced to an opposite color bishop ending with white one pawn up and a passer on the king side. Stockfish's eval was very high, Leela was less convinced.

The position was less drawish than usual for such endings. The black bishop had no pawn targets, Stockfish gave one pawn and captured two. The black king had to choose sides and could not create a passer on the queen side. The white king supported the passer on the king side, Stockfish promoted the passer and then exchanged pieces. It then queened another passer to win. There were two white wins in this game pair, the score is 1-1.

Games 3-4 started with a rare sideline of the Caro Kann advance variation. In game 3 the engines exchanged minor pieces and on move 20 the game reached a QRR vs QRR position. Stockfish's eval dropped to 0, Leela had a passer in the center but it couldn't move it forward. The white king walked to the queen side, Stockfish attacked with its queen and Leela exchanged queens. The engines shuffled until Leela lowered its eval for the draw rule.

In game 4 the engines exchanged a few minor pieces and Stockfish created a passer in the center. The engines exchanged a pair of pawns on the queen side, both queens were there but were not exchanged. Evals remained stable until move 32.

The engines seemed to shuffle but evals slowly increased. On move 47 a pawn exchange opened the a file. Leela captured a pawn and surprised Stockfish, Stockfish's eval dropped below 1 but then Leela again did not play what Stockfish expected and its eval shot back up. A series of exchanges reduced to a QRB vs QRN position.

Stockfish used the exposed black king to capture a pawn. Leela regained the pawn and exchanged queens. Stockfish then captured two pawns and Leela lost the rook for a passer. Stockfish created another passer, queened and mated. Stockfish wins the game pair, it leads 2-1.

Games 5-6 started with the King's gambit, bishop gambit Bledow variation, with a bias for black. The black queen was out on the king side and the white king moved without castling. In game 5 the engines exchanged queens after Stockfish castled. Stockfish pushed pawns on the king side, evals came down in a long PV agreement where Leela gave a rook for a knight and pawn. Most king side pawns were gone, Leela gave the second rook for a bishop and pawn. The black king moved forward and the engines reduced to a BBN vs RRB position. Leela had a passer in the center, Stockfish moved its rooks forward to attack the white king and chose to end the game in repetition. In game 6 the engines played out a long PV agreement in which they exchanged queens and Leela castled long. Stockfish's eval came down, Leela moved its knights forward and its eval stayed close to 1. The black knights were exchanged and the game reached a RRB vs RRB position, Leela with two passers. Stockfish captured one passer, Leela pushed the other to the 2nd rank blocked by a rook. The engines shuffled, after exchanging a pair of rooks Leela lowered its eval enough for adjudication.

Games 7-8 started with a rare line in the Sicilian Kan, Swiss cheese variation. In game 7 the engines exchanged a pair of knights and opened the d file. Leela blocked the file with a bishop and pushed pawns on the queen side. Stockfish moved a rook forward and sacrificed it for a bishop and pawn. Stockfish's eval came down, the engines reduced to a QRB vs QBN position and started to shuffle. After exchanging minor pieces the shuffling resumed, the game was adjudicated on move 115 after Leela lowered its eval.

In game 8 a series of exchanges in a PV agreement opened the c file, a few minor pieces were exchanged and evals increased. Leela created a passer in the center, Stockfish pushed a pawn to h6 and then created its own passer in the center. Stockfish captured a pawn on the king side and the h pawn became a passer as well, a series of exchanges reduced to a double rook ending with white two pawns up.

Stockfish let the h pawn be taken, it blocked the black passer and both kings moved to the queen side. Stockfish captured all the black pawns, the black king became trapped, Leela lost material and was mated. Stockfish won the game pair, it leads 3-1. 

Games 9-10 started with a 20-ply sideline of the KID fianchetto, classical main line.  In game 9 the center was blocked, the engines opened the c file. The engines pushed pawns on the queen side and opened the a file. All rooks were exchanged and after a while the queens were also exchanged. The game reached a BB vs NN position and the engines started to shuffle. Close to the 50-move limit Leela lowered its eval and the game was adjudicated on move 100.

In game 10 the engines repeated the reverse game for 10 plys, again opening the c file. The engines played out a long PV agreement, exchanging minor pieces and a pair of pawns and evals stayed stable. For a while the engines semmed to shuffle, though Stockfish's eval slowly increased. On move 36 Stockfish opened the center. 

It took Leela 3 more moves to see that it was in trouble. It surrounded its king with the major pieces while Stockfish captured the two supporting pawns on the king side. In a series of exchanges the queens were gone and Stockfish traded two bishops for a rook. Stockfish had connected passers on the king side, Leela gave back the two bishops for a rook to capture one passer. The game reached a RN vs RN position.

It took a while for Stockfish to push its passer, then it gave the rook for a knight and queened the passer, followed by mate. Stockfish wins the game pair, it leads 4-1.

Season 28 premier division statistics

A summary statistics table of previous stages and seasons. 

Draw rate, wins

Final draw rate was 59.4%. 

Game termination

The three most common game termination causes were:
47.8% - TCEC draw rule
40.6% - Mate
5.8% - 3-Fold repetition
5.8% - Fifty moves rule

There were no crashes in the stage.

Moves per game

Median= 81.5
Average= 86.2

There were 57 games longer than 100 moves, the longest was 270 moves (KomodoDragon - Ethereal, game 90, draw). 

Time per game (hours)

Median= 2:11
Average= 2:06

Openings

There were variable length book openings in this stage. The first letter of the ECO codes was distributed as follows: 

The engines had almost no freedom to choose the opening variant, all of the game pairs repeated the same ECO code and the opening variant twice.

Reverse pairs, wins

Reverse pairs, same moves

Pairs of reverse games diverged less quickly than usual, 12.5% diverged immediately out of book, 54.4% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 23 plys (Stockfish - Berserk, games 73 and 101, French Winawer, advance variation, Stockfish won as white).

Season 28 premier division final results

Final Standings

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

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

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

Interesting games

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Featured game: Leela - Stockfish
game 206

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

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

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

Season 28 premier division, after RR6

Standings after RR6

Stockfish extended its lead, it had 4 game pair wins in DRR3. Leela is now in second place after struggling in the first two DRRs. In this DRR Leela had 3 game pair wins without loss, including a win against Integral that was in second place after DRR2. Integral had a poor DRR with two game pair losses and no win, quite unexpected after its results in the previous rounds. As a result Integral dropped to 4th place, Obsidian is now in 3rd. Leela opened a small gap, but we may still see an upset in the superfinal qualification, depending on the results of the last DRR. 

Ethereal is alone at the bottom of the table after 3 game pair losses in the DRR. KomodoDragon was better than the previous DRR, it had two wins and two losses and got a bit closer to Berserk (one loss, no wins). 

Interesting games

game 113, Leela - Berserk: There was one minor piece exchange after the start, Leela's eval increased quickly and went over 3. The engines played behind their pawn lines, there was a long shuffle and the white king walked to the queen side. Leela's eval peaked close to 5 and slowly drifted down. On move 87 Leela moved a pawn and reset the 50 move counter, the engines exchanged a few pieces and pawns and evals increased again. Leela captured a pawn and opened the a file, Berserk placed its major pieces there and threatened the white king. Leela defended its king and exchanged all rooks, the game reached a QN vs QB position. Berserk sacrificed the bishop for a pawn to create a passer, Leela pushed a pawn on the queen side and exchanged queens. The white passer was faster, Leela queened and mated.

game 115, Stockfish - Ethereal: The center was blocked, after a few minor piece exchanges the engines opened the g file and exchanged a pair of rooks. Stockfish sacrificed a knight for two pawns and reduced to a QB vs QBN position. The white king walked to the queen side, Stockfish captured another pawn and created connected passers. After exchanging queens Ethereal tried to control the white passers, it gave a bishop for a pawn and delayed for a while. Stockfish gave back the bishop for a pawn, Ethereal captured the white passers but the white king moved forward and captured two pawns on the queen side. Ethereal lost the knight for a passer, Stockfish queened another to win.

game 120, Leela - PlentyChess: PlentyChess was up a pawn but its queen side pieces developed slowly. PlentyChess created a passer on the queen side and the engines exchanged queens. After exchanging minor pieces PlentyChess connected a second passer, also creating a passer in the center for Leela. The game reached a RRB vs RRN position, PlentyChess captured the white passer and Leela captured one of the black passers. The engines exchanged a pair of rooks and Leela captured a pawn, creating a passer on the queen side. Leela pushed the passer and captured more pawns, after exchanging rooks Leela queened the passer and mated.

game 124, Obsidian - Ethereal: There were no exchanges after the start, on move 27 the engines exchanged minor pieces and a few moves later queens were exchanged. The first pawn exchange was on move 35, Ethereal created a passer in the center. In a series of exchanges the engines reduced to a RRB vs RBN position, Obsidian had a passer on the king side but the black passer was on the 3rd rank. Ethereal created a second passer on the queen side, Obsidian captured it and exchanged a pair of rooks. Obsidian captured the black passer and Ethereal captured 2 pawns, leaving an 8-man position with one pawn for each engine. In the slow endgame the white king moved forward and Obsidian pushed the passer. Obsidian gave the rook for the bishop, queened the passer and mated.

game 126, Integral - Obsidian: The center was blocked, Integral pushed pawns on the king side and castled its king, Obsidian pushed pawns on the queen side and kept its king in the center. The engines opened the b file and Obsidian moved a rook forward. The engines exchanged a pair of rooks and Obsidian moved the queen forward. Integral opened the g file and the engines exchanged queens, Integral moved its pieces to the king side and forced the black king to move away. In a series of exchanges Obsidian lost a minor piece and the game reached a RBN vs RB position. Integral captured the black pawns, Obsidian lost more material and was mated.

game 130, KomodoDragon - PlentyChess: The center was blocked, KomodoDragon pushed pawns on the queen side and formed a pawn diagonal line. The black light square bishop could not move and it blocked the rook development. PlentyChess pushed pawns on the king side, the white king walked to the queen side. The engines opened the g file and PlentyChess moved pieces forward on the king side. KomodoDragon traded its queen for a rook and a knight, then moved its pieces to the opening on the king side. PlentyChess managed to exchange its trapped bishop, but its other bishop blocked the rook. PlentyChess exchanged the second bishop and freed its rook, but KomodoDragon captured pawns on the queen side and created passers. PlentyChess lost the rook for a passer, lost the knight for another and mate followed.

game 131, Obsidian - Leela: The engines exchanged a pair of pawns on the queen side, Obsidian closed the pawn line with a bishop. After some shuffling a knight replaced the bishop, the engines exchanged a pair of knights. Leela attacked the center with another pawn exchange, evals started to increase slowly. On move 43 the engines started to play out a long PV agreement, Obsidian gave a rook for a bishop and the engines reduced to a QRB vs QRR position. Obsidian was a pawn up with a passer in the center, Leela couldn't get rid of the passer. After 25 moves Obsidian attacked the black king, Leela exchanged pieces and lost material. The game reached a rook ending with no black pawns, a win for Obsidian.

game 134, Leela - Ethereal: The engines opened the d file and exchanged minor pieces. Ethereal placed a rook on the open file, Leela pushed pawns on the king side and opened the h file. Ethereal gave a rook for a knight and pawn to threaten the exposed white king. Leela exchanged pieces and reduced to a RRB vs RNN position. The engines exchanged pawns and each had a passer on the queen side. Ethereal traded pawns on the king side, as a result all pawns there were gone and all pieces moved to the queen side. Leela improved very slowly, eventually it was able to push the passer and exchange rooks. Ethereal lost material for the passer, followed by mate.

game 135, PlentyChess - Obsidian: There were two pawn exchanges after the start, the engines opened the a file but only much later Obsidian moved a rook there. A knight exchange on move 30 created a white passer in the center. Obsidian moved pieces forward on the queen side while PlentyChess threatened the black king on the king side. After a few more piece exchanges PlentyChess captured a pawn and pushed a second passer to the 7th rank. Obsidian captured this passer but lost another pawn, the game reached a RB vs RB position. PlentyChess pushed passers forward, Obsidian lost the bishop  but couldn't stop the passers. PlentyChess exchanged rooks, queened a passer and mated.

game 136, Stockfish - KomodoDragon: The center was blocked, Stockfish pushed pawns on the king side. KomodoDragon captured a pawn and created a passer, Stockfish moved pieces to the king side. KomodoDragon exchanged minor pieces, the white king hid behind the black passer. KomodoDragon tried to open the queen side, but instead lost two pawns and gave Stockfish passers. In a series of exchanges KomodoDragon lost a bishop for a pawn, Stockfish pushed passers forward and queened one, followed by mate.

Standings after RR5: Stockfish +9, Integral Leela +7, Obsidian +4, PlentyChess -2, Berserk -6, KomodoDragon -8, Ethereal -11. Stockfish keeps its small lead after two wins in RR5, with one draw as white against a low ranked engine. Integral had only one win, Leela managed to catch up with it after 3 wins in RR5 and despite a loss to Obsidian. At the bottom of the table Ethereal dropped down after 3 losses. KomodoDragon is a small step closer to Berserk but still facing relegation.

game 144, Obsidian - KomodoDragon: Obsidian castled long and KomodoDragon pushed pawns on the queen side. There were many piece exchanges after the start and the game reached a RRN vs RRN position on move 24. The engines exchanged pawns, KomodoDragon pushed two pawns in the center while Obsidian moved its rooks forward. KomodoDragon created an advanced passer and a white rook blocked it on the 2nd rank. KomodoDragon couldn't defend its passer, Obsidian captured it and exchanged a pair of rooks. Obsidian created a passer on the queen side and then captured a second pawn. After another pawn trade Obsidian pushed a passer forward and KomodoDragon couldn't avoid a queening and mate.

game 146, KomodoDragon - Ethereal: The white queen moved forward on the king side but Ethereal drove it back. KomodoDragon pushed pawns across the board, after a pawn exchange on the king side the black king walked back to the center. KomodoDragon exchanged a pair of rooks, captured a pawn and cleared the king side pawns. The game reached a RN vs RN position, KomodoDragon captured a second pawn and created a passer. Ethereal regained one pawn while the white king moved forward and KomodoDragon pushed the passer forward. Ethereal equalized material but lost the rook for the passer, KomodoDragon queened another and mated.

game 147, Stockfish - Integral: see featured game below.

game 154, Obsidian - Integral: Obsidian pushed pawns on the king side and Integral pushed pawns on the queen side. The engines castled their kings away from the opponent's advancing pawns. A pawn exchange opened the f file, another pawn exchange on the queen side didn't open a file but Integral created a passer on b3. Integral captured a pawn on the king side and created a passer, but it lost the queen side passer. The engines exchanged a pair of rooks, Integral moved a rook forward on the queen side and Obsidian moved the queen forward on the king side. Obsidian captured the black passer, it increased the pressure on the back ranks, created a passer on the king side and captured another pawn on the queen side. Obsidian managed to exchange queens and capture a bishop, Integral couldn't stop a queening, it lost more material and was mated. There were two white wins in this game pair. 

game 159, Leela - Obsidian: The engines opened the c file, Obsidian moved a rook forward. Leela trapped the rook, Obsidian chose to trade the rook for a bishop and to activate its king side bishop. The engines exchanged minor pieces, Obsidian pushed pawns on the king side and its bishop became blocked again by its own pawns. Leela moved its major pieces to the king side, the h pawn became a passer. Then Leela shifted to the queen side, the white queen moved forward. Leela moved a rook forward and captured a pawn, creating a second passer. Obsidian lost material trying to defend its king, but was quickly mated. There were two white wins in this game pair.

game 162, Ethereal - Leela: Leela pushed pawns on the king side, Ethereal gave two pawns in the center and opened the e file. The white queen moved forward on the king side, after a series of exchanges the game reached a QRN vs QRB position on move 24. Ethereal regained one pawn, it tried for a long time to find the right way to attack. Leela avoided piece exchanges, after 30 moves Ethereal started to capture pawns. Ethereal was two pawns up with a passer when it exchanged rooks, Leela lost the bishop for another passer. Ethereal exchanged queens, queened a passer and mated. There were two white wins in this game pair.

game 163, Obsidian - PlentyChess: The engines opened the a file, after another pawn exchange Obsidian moved a rook forward. From move 22 the engines exchanged pieces and pawns, resulting in a N vs B ending on move 34. Obsidian was a pawn up with a passer on the queen side. Obsidian slowly pushed the passer forward to the 7th rank, PlentyChess did not take the passer to keep the white king away from the black pawns. After move 63 Obsidian captured the two black pawns, PlentyChess captured the passer on the queen side but couldn't avoid a queening and mate. There were two white wins in this game pair. 

game 166, Stockfish - Obsidian: Stockfish pushed pawns on the king side, Obsidian opened the c file and moved a rook forward. Obsidian created a passer on the queen side, Stockfish gave a pawn and both engines created a passer in the center. After exchanging queens both engines pushed passers forward, Stockfish blocked the king side with a pawn on g6, trapping the black king. Stockfish captured one passer, Obsidian gave a bishop for the white passer. Obsidian lost control of the back rank, it lost more and more material and was mated.

game 167, PlentyChess - Ethereal: Evals were more or less stable as the engines exchanged pieces and pawns, even after Ethereal gave a rook for a bishop. The game reached a RR bs RB position, Ethereal exchanged a pair of rooks and PlentyChess' eval jumped. The 8-man position may have been a win, at least according to the Stockfish analysis that followed the game. However PlentyChess just shuffled and the game was adjudicated a draw close to the 50 move limit.

game 168, Leela - Integral: Evals increased quickly after the start. Leela pushed pawns on the king side and threatened the black king with a rook on h3, then captured a pawn on the queen side. The black pieces became passive, Integral gave a rook for a bishop to activate its queen. Leela pushed a pawn and created a passer on the queen side. An exchange of a pair of rooks connected a second white passer, Leela pushed the passers and Integral lost material. Leela trapped the black king and mated.

Featured game: Stockfish - Integral
game 147

After both engines castled the attention was on the queen side, both engines pushed pawns and there was one pawn exchange. After move 25 Stockfish shifted to the king side, it opened the h file and evals jumped. A minor piece exchange opened the d file, then Stockfish captured a rook for a bishop and pawn.

Stockfish moved a rook forward on the d file. A pawn exchange on the queen side created a passer for each engine. Integral gave the passer away and moved major pieces to the h file. Stockfish gave the passer back, exchanged rooks and took over the h file. The game reached a QR vs QB position, again each engine with a passer.

Integral tried to attack the white king but was not strong enough. Stockfish captured the black passer and pushed its own, Integral lost the bishop to stop it. Integral tried to protect its king, eventually it lost the queen and was mated.

Season 28 premier division, after RR4

Standings after RR4

Stockfish and Integral continue to lead, both had 4 game pair wins and two losses in the second DRR. Stockfish lost to Leela and to Integral, yet its results against lower ranking engines is better. Integral lost to Leela and Obsidian. Leela is in 3rd place after 3 game pair wins and no loss. It won against Stockfish and Integral, but only had one more win against the other engines.

KomodoDragon had a terrible DRR with 6 game pair losses, it dropped to last place. Berserk had only one game pair loss, it has a 1.5 points gap to Ethereal in 7th place.

Interesting games

game 59, Stockfish - Ethereal: The engines blocked the center, there was one pawn exchange on the queen side. The engines exchanged a pair of knights on move 33, evals slowly increased though the engines appeared to be shuffling. On move 57 Stockfish exchanged pawns on the king side, then it captured a pawn and created connected passers on the queen side. Ethereal exchanged pieces and gave a bishop for the white passers, reducing to a RB vs R position. Stockfish pushed two passers forward, Ethereal lost material and was mated.

game 61, Berserk - Obsidian: There was one pawn exchange in the center, the engines arranged their pawn lines and shuffled with evals increasing slowly. The first pieces were exchanged on move 31, a second pawn exchange opened two files. The engines exchanged all knights, both engines created a passer in the center and Berserk captured a pawn. Berserk created a second passer and captured a second pawn, it pushed its passers to the 6th rank. Obsidian tried to block, in a series of exchanges it lost all pieces and Berserk was left with a queen, mate followed.

game 62, Ethereal - KomodoDragon: The engines gradually exchanged pieces and pawns including queens, evals increased slowly. On move 53 the game reached a RRB vs RRB position, a few moves later Ethereal exchanged a pair of rooks, captured a pawn and created a passer in the center. The white king moved forward and Ethereal captured two more pawns. Ethereal gave a rook for a bishop, queened a passer and mated.

game 63, Integral - Stockfish: see featured game below.

game 65, PlentyChess - Berserk: PlentyChess pushed pawns on the king side and castled long. Berserk tried to attack on the queen side, in a series of exchanges PlentyChess gave the queen for two bishops. Berserk then gave a rook for a knight, the black king was under threat after PlentyChess opened the h file. PlentyChess created a passer on the queen side, it gave material and queened. The game reached a QB vs Q ending with black two pawns up. Berserk had a passer on the 2nd rank, PlentyChess managed to prevent a queening while also pushing its own passer slowly. The engines exchanged queens, both queened and then exchanged queens again. In the end PlentyChess mated with a bishop and a pawn.

game 68, Obsidian - Ethereal: The engines exchanged pawns on the king side, Obsidian walked its king to the queen side. The black king had no pawn support, more pieces were exchanged until only QN vs QB remained. Obsidian captured a pawn, it pushed a passer slowly forward. After exchanging queens Ethereal couldn't stop a queening followed by mate.

game 69, Berserk - Ethereal: Berserk was up a pawn early. After some shuffling and pawn moves there was a series of exchanges that led to a R vs BN imbalance. The engines cleared the queen side pawns and continued to exchange pieces until reaching an opposite color bishop ending. Berserk was two pawns up, Ethereal captured two pawns but by then Berserk had advanced connected passers. Berserk captured the last black pawns, queened passers and mated.

game 71, Leela - KomodoDragon: There were many early exchanges including queens, Leela kept its king in the center. The game reached a RRB vs RRB position, Leela captured a pawn and pushed a pawn to e6. KomodoDragon avoided capturing the pawn and hid its king behind it. KomodoDragon regained the pawn, it tried to keep the board blocked but Leela gave a rook for a bishop and moved a rook to the 7th rank. Leela captured a pawn and created another passer on the 6th rank, KomodoDragon lost material and was mated.

game 73, Stockfish - Berserk: There were a few exchanges after the start, the white queen was out on the king side. Berserk preferred to walk its king to the queen side for safety. All pieces moved to the queen side, Berserk captured a pawn and Stockfish trapped a rook in the center. Berserk lost the rook for a knight and evals started to increase in a QRR vs QRN position. Stockfish threatened the black king while pushing pawns, it captured a pawn and created a passer on the king side. Stockfish opened the center and exchanged a pair of rooks, at the right time it exchanged all remaining pieces and queened the passer. The black pawns were too slow, Stockfish queened again and mated.

game 79, PlentyChess - Obsidian: The engines castled in opposite directions, opened the e file and gradually exchanged pieces. The game reached a QRB vs QRN position, PlentyChess had a passer in the center and it also captured a pawn. Obsidian blocked the passer, for a while the engines seemed to be shuffling. Obsidian gave a pawn to increase the activity of its queen, then captured a pawn back. PlentyChess reduced to a B vs N ending, Obsidian lost its knight and both engines queened a passer. After exchanging queens PlentyChess queened again to win.

game 80, Stockfish - KomodoDragon: KomodoDragon gave a rook for a bishop early. Stockfish pushed pawns on the king side, it opened the h file and captured a pawn, the black king ran to the center for safety. KomodoDragon traded two knights for a rook and pawn, the game reached a QRB vs QR position. Stockfish tried to exchange pieces and KomodoDragon avoided the exchanges, after 30 moves Stockfish exchanged queens. Stockfish captured a pawn and created a passer, KomodoDragon lost its rook for the passer and was mated.

Standings after RR3: Stockfish +7, Integral +5, Leela +3, PlentyChess +1, Obsidian 0, Berserk -4, KomodoDragon -5, Ethereal -7. Stockfish is in the lead, despite losing to Integral. Stockfish won 3 games as white and drew as white against Leela. Integral is in second place, apart from the surprising win against Stockfish it drew as white against Leela and Obsidian. Leela is still in third place after drawing 3 times against lower ranked engines and only winning once. At the bottom KomodoDragon had 3 losses without a win, it is now in 7th place behind Berserk which had a good RR with two wins and two losses.

game 86, Integral - PlentyChess: The engines opened a file on the queen side, Integral kept its king in the center. The engines exchanged all bishops and a pair of rooks, evals started to increase. The white king walked to the king side, the engines reduced to a double knight ending. The white knights had more space to maneuver, after 20 moves Integral captured a pawn and created a passer on the queen side. Integral gave a knight for two pawns, PlentyChess captured the passer but now Integral had 3 more. The white king moved forward, PlentyChess lost a knight for a passer and gave up the other knight with mate following.

game 88, Obsidian - KomodoDragon: The engines opened a file on the queen side, Obsidian moved the queen forward and grabbed a pawn. KomodoDragon had a bishop pair advantage, after some shuffling the major pieces concentrated on the queen side. After a knight for bishop exchange KomodoDragon captured a pawn and created a passer. Obsidian had more attackers than KomodoDragon's defenders, Obsidian captured the passer and reduced to a QN vs QB position. KomodoDragon had a weak pawn that its bishop could not defend, Obsidian was patient and only after a few pawn trades and 20 moves it captured the pawn. Obsidian pushed a passer forward, KomodoDragon blocked but its king was trapped and mated.

game 89, Obsidian - Berserk: There was one pawn exchange after the start, Obsidian pushed pawns on the queen side. On move 27 the engines exchanged a pair of bishops, after some shuffling there was a series of exchanges that reduced to a RNN vs RBN position. After exchanging a pair of knights Obsidian captured a pawn and created an advanced passer on the queen side. Berserk couldn't avoid a queening followed by mate. There were two white wins in this game pair.

game 93, Berserk - PlentyChess: The engines opened the center and started to exchange pieces. Berserk captured a rook for a bishop and pawn, the game reached a QRB vs QBN position. Berserk pushed a passer, then gave the rook for a bishop. It then gave the queen for a knight and queened the passer, resulting in a QB vs Q ending. PlentyChess captured pawns, Berserk pushed one last pawn slowly forward. PlentyChess delayed with checks as much as it could, eventually Berserk queened and mated. There were two white wins in this game pair.

game 94, Leela - Stockfish: The engines opened the center and exchanged pieces and pawns, queens were exchanged and the black king moved without castling. Leela captured a pawn, the game reached a BB vs BN position on move 26, white a pawn up with doubled pawns. Leela improved very slowly, using its bishop pair advantage. After 25 moves Leela created a passer and got rid of the doubled pawns. After 20 more moves the passer started to advance, then Leela captured another pawn and created a second passer. Stockfish couldn't stop both passers, it exchanged all pieces, Leela queened and mated.

game 95, Integral - KomodoDragon: There was one minor piece exchange after the start, both engines castled long. After a period of mostly shuffling the engines opened the king side and started to exchange pieces. Integral gave a bishop, then captured the queen for a rook to get a Q vs RB ending. Integral used attacks on the black king, it captured a pawn and created a passer. KomodoDragon blocked the passer on the 7th rank, it lost material and was mated.

game 97, Ethereal - Berserk: Ethereal was up a pawn early, the engines exchanged pieces and pawns and Ethereal created a passer on the queen side. The game reached a RB vs RN position, Ethereal played patiently and didn't push the passer forward. The black king moved to the queen side, Ethereal captured a second pawn and created a passer on the king side. Berserk captured the queen side passer but lost all its pawns, it lost its pieces for the remaining white pawns and was mated. There were two white wins in this game pair.

game 98, Obsidian - Integral: There was one pair of bishops exchanged after the start, the black queen moved forward on the king side. After a pawn exchange Obsidian created a passer in the center and the queens were exchanged. The engines blocked the queen side and shuffled for a while, Obsidian walked its king to the queen side and doubled rooks on the g file. The engines opened the king side and reduced to a RNN vs RBN position, Integral lost the rook for a passer, Obsidian trapped and captured the bishop. Obsidian queened a passer to win.

game 100, Stockfish - PlentyChess: There were a few exchanges after the start, the engines shuffled for a while without moving pawns. Stockfish slowly pushed pawns on the king side, evals increased a little. Stockfish created a passer in the center, then gave two pawns and evals jumped. PlentyChess gave a rook and pushed connected passers on the king side, Stockfish gave the rook back for two black passers. In a QRB vs QRB position Stockfish had a passer on the 7th rank, it forced a queen exchange and confined the black king to the h file. PlentyChess exchanged rooks, when the white king moved forward PlentyChess lost the bishop for a passer. Stockfish queened another passer to win.

game 102, PlentyChess - KomodoDragon: There were a few exchanges after the start, PlentyChess had more space. In a series of exchanges the engines opened the center and exchanged queens, PlentyChess captured a pawn on the queen side. PlentyChess gave a pawn creating a passer on the queen side for itself and for KomodoDragon. In a series of exchanges the engines reduced to a double rook ending, KomodoDragon was a pawn up but PlentyChess had an advanced passer. PlentyChess lost the passer but captured two pawns on the king side, KomodoDragon lost material and was mated.

game 104, Integral - Ethereal: Integral pushed pawns on the king side, Ethereal exchanged queens and the g file opened. Integral captured a pawn, the engines continued to exchange pieces until only B vs N were left. Integral traded pawns, the white king moved forward to support a passer and Ethereal couldn't stop a queening and mate. 

game 107, Obsidian - PlentyChess: There were no exchanges after the start, the engines castled in opposite directions. Obsidian pushed pawns on the king side until they met the black pawns and blocked the king side. PlentyChess opened the center, the engines exchanged pieces and reduced to a QRN vs QRN position. Obsidian captured a pawn and created a passer on the queen side, it pushed the passer forward slowly. PlentyChess managed to capture the passer but Obsidian captured a pawn on the king side and created a passer there. PlentyChess lost the queen for this passer, mate followed. There were two white wins in this game pair. 

game 111, PlentyChess - Ethereal: There were no exchanges after the start, the engines blocked the center. Ethereal captured a pawn but evals increased steadily. PlentyChess pushed pawns on the king side, it created a passer with a pawn exchange. Another pawn exchange opened the b file, PlentyChess moved a rook forward and the black major pieces were on the other side. Ethereal gave a pawn and tried to hide its king behind it, PlentyChess moved its queen forward on the queen side. PlentyChess exchanged pieces to relieve the pressure on the back ranks, the queens were exchanged and Ethereal lost minor pieces. PlentyChess moved its second rook forward and forced mate.

game 112, Leela - Integral: The center was blocked, there were a few exchanges after the start including queens. The first pawn exchange was on move 31, Leela pushed pawns on the king side and opened the h file, the engines exchanged a pair of rooks. Leela then shifted to the queen side, it captured a pawn and reduced to a RNN vs RBN position. Leela gave back the pawn and created a passer on the queen side. After exchanging knights Leela had passers on the king side as well, Integral couldn't stop them all it lost the rook and was mated. 

Featured game: Integral - Stockfish
game 63

The engines opened the center, Stockfish castled long and Integral kept its king in the center. Evals increased gradually, Integral opened the h file and moved its king to the king side. The black pawns were mostly undeveloped in the center and king side, on move 29 Stockfish pushed the e pawn to add some space for its pieces. This created a passer in the center for Stockfish, while also creating a pawn majority on the king side for Integral.

Stockfish kept a rook on the king side to watch the white pawns. Integral exchanged a pair of pawns on the queen side and the black queen had to keep the black king safe. After patient preparation Integral managed to capture a pawn and create a passer in the center. Then it captured the black passer and reduced to a QRR vs QRR position, with two more passers on the king side. 

Integral threatened the black king, Stockfish captured one of the passers and Integral forced a queen exchange. Stockfish lost a rook for a passer, Integral queened another and mated.