Season 26 superfinal games 1-10

After 10 games Stockfish leads 2-1 with 7 draws. Stockfish won two of the first 3 game pairs, then Leela won a game pair and reduced Stockfish's lead to one. Stockfish's first win was a slow eval increase in a position that seemed to be drawn. Its second win was a long Q vs RN ending where Leela (white) thought it was safe for a while. Leela's win was the result of inaccurate moves by Stockfish at the start.

The opening book was created by Jeroen Noomen, details can be found here. Openings were taken from games of chess masters of the past, this season 18 of the openings were from Mikhail Tal's games.

Games 1-2 started with a variant of the Czech Benoni defense. In game 1 there were many exchanges after the start, the game reached a RN vs RN position on move 23. Stockfish defended a weak backward pawn and didn't allow Leela to invade with its rook. The engines shuffled and evals slowly came down until the game was adjudicated on move 80. 

In game 2 there almost no exchanges after the start, the center was blocked and the engines played behind their pawn lines. Stockfish moved its king forward instead of castling, after move 21 there were a few pawn exchanges, then in a series of exchanges the engines opened the queen side and exchanged queens. Evals were low at this stage.

The engines seemed to shuffle for a long time but evals very slowly increased. On move 68 Stockfish opened the h file and on move 80 the engines exchanged a pair of rooks. Evals were already over 2, both engines with a minute left and playing on increments.

The engines exchanged the remaining pawns on the king side and the white king moved forward. In a series of exchanges the engines reduced to a rook ending and Stockfish saw the win. Using a threat of a back rank mate Stockfish captured a pawn and created a passer. Leela lost the rook and the game ended in a tablebase win. Stockfish wins the game pair, it leads 1-0.

Games 3-4 started with a 24-ply variant of the Sicilian Sozin attack, flank variation. The center white pawns were gone, black was a pawn up but its pieces were mostly on their starting squares. In game 3 Stockfish gave a rook for a bishop and protected its exposed king in the center. Leela thought it had an advantage but its eval dropped when the black king found safety and Stockfish developed its pieces. Leela captured two pawns but after a series of exchanges the game reached an opposite color bishop ending. The engines shuffled and the game was adjudicated on move 105 when Leela lowered its eval. In game 4 Stockfish captured a rook for a bishop though not by the same line as in game 3. Evals came down quickly, the engines exchanged minor pieces and shuffled for a while. The game reached a QRR vs QRB position, Stockfish used check to capture two pawns and created passers on the queen side. Leela countered with an attack on the white king, after sacrificing a rook Leela forced a 3-fold repetition draw.

Games 5-6 started with a 25-ply variant of the King's Indian defense, Saemich variation. There was a Q vs BN imbalance but black had the advantage. In game 5 Stockfish captured two pawns quickly and created a passer in the center. Leela captured the passer and Stockfish exposed the white king with two forward knights. Stockfish also had a strong bishop controlling the dark long diagonal. Leela gave a rook for the black bishop, the game reached a QR vs RRN position with black 3 pawns up.

Leela's (negative) eval drifted down while Stockfish's slowly increased. Leela captured the black d pawn, the engines exchanged a pair of rooks, Stockfish had a pawn majority on both sides of the board. Stockfish slowly pushed pawns on the king side, it created a passer there and another on the queen side after a pawn exchange. Stockfish saw the win but when Leela captured the queen side passer its eval dropped below 1 again. 

It took Leela 8 moves to realize it was actually losing. The black king moved forward and Stockfish captured the last white pawn. The white king was trapped and the game ended in mate.

In game 6 Stockfish defended in a different way as white, it exchanged a pair of knights and kept its king safe. Leela gave a rook for a bishop and tried to attack the white king, Stockfish traded a rook for a knight and reduced to a QR vs RBB position. Stockfish placed its pieces on the back rank, the white king moved forward and used black pawns as shields. Stockfish traded its rook for a bishop, the game continued for 30 more moves with Stockfish mostly giving checks until Leela lowered its eval for the draw rule. Stockfish wins the game pair, it leads 2-0.

Games 7-8 started with a 28-ply line in the Ruy Lopez, Chigorin variation. The center was blocked and all pieces and pawns were on the board. In game 7 Stockfish exchanged pawns on the queen side and Leela thought that was a mistake. Stockfish's eval stayed around 1 while Leela's eval increased, by move 27 two files were open on the queen side and the engines exchanged a pair of rooks.

Leela avoided exchanging queens, Stockfish started to see trouble ahead. The engines exchanged the remaining rooks and then Leela captured a pawn and created a passer on the queen side. Leela captured a second pawn, then after a series of exchanges the game reached a BN vs BN position, white two pawns up with connected passers on the queen side. 

The engines traded pawns, Stockfish captured one passer and Leela created another on the king side. Stockfish couldn't prevent a queening and the game ended in a tablebase win.

In game 8 the queen side stayed closed, there was only one minor piece exchange after the start and all pawns stayed on the board. Stockfish tried to threaten the king side but nothing came out of it. The first pawn exchange was on move 32, Stockfish created a passer in the center and Leela blocked it. The engines exchanged more minor pieces and evals came down. In a series of exchanges the engines reduced to a rook ending. Stockfish's eval was 0, it took Leela another 20 moves to lower its eval for the draw rule. Leela wins the game pair, Stockfish leads 2-1.

Games 9-10 started with the old Indian defense, Janowski variation. In game 9 there were a few exchanges after the start, the engines opened the e file. The black queen moved forward on the queen side and evals came down. In a series of exchanges Leela captured two pawns and the game reached a QRB vs QRB position. Stockfish captured one pawn back and exchanged queens. The engines traded pawns and Leela regained the pawn, it was two pawns up with two passers but Stockfish managed to capture a pawn and its last pawn was also a passer. Leela pushed one passer to the 7th rank but there it was blocked. The game was adjudicated 20 moves later when Leela lowered its eval. Game 10 repeated 14 plys of game 9, the engines opened the e file. Stockfish grabbed a pawn with its queen, which then became trapped on the queen side. After a while Stockfish freed its queen, the engines exchanged a pair of rooks and then mostly shuffled for a long time. Evals slowly started to increase and were both over 1. On move 98 the game reached a BN vs BN position and then evals dropped. The engines shuffled again and the game was adjudicated. Was this a missed opportunity for Stockfish?

Season 26 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:
51.3% - TCEC draw rule
22.3% - Mate
19.6% - SyzygyTB

There were no crashes in the stage.

Moves per game

Median= 71
Average= 79.0

There were 41 games longer than 100 moves, the longest was 251 moves (Ethereal - RubiChess, game 51, draw). 

Time per game (hours)

Median= 2:05
Average= 2:02

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, 19.6% diverged immediately out of book, 48.2% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 25 plys (Stoofvlees - RubiChess, games 139 and 167, Vienna Frankenstein-Dracula variation, RubiChess won as white) 

Season 26 premier division, final results

Final standings

Stockfish and Leela will play in the season 26 superfinal, a repeat of the last 3 superfinals. They were in the lead from the start and only increased the gap to the other engines as the rounds progressed. Stockfish won 20/24 game pairs against the other 6 engines, Leela won 17/24, both without losing a game pair. Surprisingly Stockfish drew twice against Stoofvlees, including its only game loss in the division. Leela had the only double win game pair of the division against RubiChess. Leela stayed very close to Stockfish for the first 3 DRRs, they were tied after 2 DRRs. In the last DRR Stockfish had a perfect result of 7/7 game pair wins including the only win against Leela, while Leela also drew against Berserk, giving Stockfish a small gap at the top.

Berserk and KomodoDragon were in the second group battling for third place. Berserk kept a small lead and also beat KomodoDragon twice in the first 2 DRRs. In the third RR KomodoDragon won their game pair and it closed to within 0.5 points. In the final DRR KomodoDragon was very close to Berserk, it managed to tie their score before the final round but lost to Stockfish to finish in 4th place. Berserk finished in 3rd after starting this season from the entrance league (it didn't play in season 25). KomodoDragon is officially out of the "top3" and no other engine seems to challenge the two leaders. It appears the KomodoDragon development team are more focused on the new Torch engine, which has yet to appear in TCEC.

At the bottom half of the table Ethereal, Seer and RubiChess were close from the start while Stoofvlees was clearly last. After 3 DRRs Seer and Ethereal were tied while RubiChess was 1 point behind. In the last DRR Seer lost to both Ethereal and RubiChess and Ethereal finished in 5th place, RubiChess couldn't close the gap and it finished in 7th, to be relegated to league 1.

Interesting games

game 172, KomodoDragon - Ethereal: The engines blocked the king side and KomodoDragon castled long. Ethereal gave a pawn and opened the c file, it later regained the pawn and placed a passer on a2. The white king hid behind the black passer, KomodoDragon pushed a pawn in the center to the 7th rank. Ethereal couldn't get rid of the protected passer, eventually it gave a rook for a knight to capture it. KomodoDragon created a passer on the king side and both engines saw the win, Ethereal lost material and was mated.

game 173, Stockfish - Ethereal: There were almost no exchanges after the start, long pawn lines blocked the queen side and the center. The engines exchanged a few minor pieces, all pawns were on the board until Stockfish captured one on move 32. Stockfish's eval started to increase, on move 44 the game reached a QRB vs QRB position. Ethereal regained the pawn but got its queen trapped in front of the pawns. Ethereal exchanged bishops and Stockfish captured another pawn, by the time the black queen was released Stockfish saw the win. The queens were exchanged and Stockfish captured another pawn, Ethereal lost its rook for a passer and was mated.

game 175, Berserk - Seer: The white king walked to the king side, there were only a few exchanges after the start, only one pawn exchange. Seer also moved its king without castling, the engines shuffled for a long time. On move 48 Berserk captured a pawn, the black king walked to the queen side and evals started to increase. The engines opened the queen side and Berserk attacked with its major pieces, capturing another pawn. The game reached a RRB vs RRB position, Berserk gradually captured all the black pawns. Seer lost material and was mated.

game 176, Leela - RubiChess: Leela castled long and RubiChess kept its king in the center. The engines exchanged a few minor pieces and RubiChess captured a pawn on the king side. Leela captured a pawn on the queen side and created a passer, then captured another pawn and exchanged queens. The black king walked to the queen side and eventually captured the passer, Leela captured a pawn on the king side and created another passer there. RubiChess lost a knight and captured the passer and another pawn, the game reached a RBN vs RB position. The white king moved forward and eventually helped in capturing the remaining black pawns. Leela had one pawn left and a piece advantage, the game ended in a tablebase win.

game 182, Berserk - Ethereal: There were no exchanges after the start, the engines played behind their pawn lines. By move 38 there were two minor piece exchanges, evals started to increase very slowly. The first pawn exchange was on move 52, then the engines exchanged a pair of rooks and both created a passer in the center. Berserk moved the queen to the back rank, Ethereal exchanged queens and the game reached a RN vs RN position. Ethereal captured the passer in the center, Berserk created connected passers on the king side and exchanged rooks. Berserk captured 3 pawns, queened a passer and mated.

game 183, Leela - KomodoDragon: There was one minor piece exchange after the start, on move 27 the engines exchanged queens. Evals increased, all pawns were on the board and Leela placed a pawn on b6. On move 43 the first pawns were exchanged and the engines opened the f file. KomodoDragon gave two pawns with no compensation, the game reached a RBN vs RBN position. Leela created passers on the queen side, it gained material and queened, the game ended in mate.

game 184, RubiChess - Seer: The engines blocked the queen side, then exchanged a pair of bishops. On move 23 the engines opened a file in the center, RubiChess opened the king side and attacked with major pieces. In a series of exchanges the engines reduced to a RN vs RN position with white a pawn up, RubiChess captured a second pawn and created connected passers on the queen side. Seer delayed with checks but eventually RubiChess queened a passer and mated.

game 186, KomodoDragon - RubiChess: There were no exchanges after the start, the engines formed long pawn lines. The pawns stabilized, on move 32 the engines exchanged a pair of knights and then started to shuffle. Pawn moves extended the 50 move counter, on move 145 the engines exchanged the first pawns and continued to shuffle. On move 186 there was another pawn exchange, then KomodoDragon gave a pawn. RubiChess gave a rook for a bishop, perhaps a mistake under time pressure. RubiChess had two passers but KomodoDragon blocked them while it sent its rooks to the back rank and captured a bishop. RubiChess got some of the material back but KomodoDragon captured the black passers and kept the advantage. The game ended in a tablebase win.

game 189, Stockfish - Berserk: Stockfish castled long while Berserk kept its king in the center. Berserk tried to attack on the queen side, Stockfish gave a pawn and opened the center. Stockfish gave a knight and threatened mate on the back rank, Berserk gave back the material and delayed with checks. Eventually Berserk gave a rook for a bishop to stop the back rank threat, the game reached a RR vs RB position. Stockfish pushed a passer and saw the win, it reduced to a rook ending and queened the passer. The game ended in a tablebase win.

game 194, Ethereal - Seer: There were no exchanges after the start, the engines played behind their pawn lines. On move 28 the engines exchanged a pair of bishops, the first pawn exchange was on move 31 opening the f file. Evals started to increase, a series of exchanges opened the queen side and both engines had a passer there. Ethereal captured the black passer and exchanged queens, it kept its passer defended. After a while the engines exchanged a pair of rooks and reduced to a RBN vs RBN position. The black crossed the board to help, Ethereal managed to get its rook to the king side to capture the black pawns there. Seer lost its last pawn, Ethereal was 3 pawns up and it pushed them forward. Seer lost material, Ethereal queened and mated.

Standings after RR7: Stockfish +17, Leela +16, Berserk +3, KomodoDragon +2, Ethereal -6,  Seer -7, RubiChess -8, Stoofvlees -17. No change in the lead after both Stockfish and Leela won their games as white against lower ranking engines. Similarly there is no change in the race for 3rd place between Berserk and KomodoDragon. Ethereal beat Seer and is now ahead in 5th place, RubiChess also beat Seer but it is still in 7th place facing relegation with Stoofvlees.

game 197, Stockfish - Leela: See featured game below. 

game 198, Berserk - RubiChess: The engines started a series of early exchanges, in the aftermath RubiChess was down a knight for two pawns and the white king was exposed in the center. Berserk was confident it had an advantage, it continued to exchange pieces until only RRN vs RR remained. RubiChess placed both rooks on the 2nd rank, Berserk was down to its last pawn and it exchanged a pair of rooks. Slowly Berserk pushed its pawn forward until it became a passer. RubiChess lost its rook and the game ended in a tablebase win.

game 199, Stoofvlees - Seer: The engines exchanged a few minor pieces and blocked the king side. On move 27 the a file opened, gradually Stoofvlees exchanged all rooks and reduced to a QBN vs QBB position. Almost all pawns were on the board and the bishops were blocked. Stoofvlees captured a pawn and opened the d file, then gave a bishop for two pawns and created a passer on the king side. After a series of exchanges the game reached a pawns vs bishop ending, Seer couldn't prevent a queening and was mated. There were two white wins in this game pair. 

game 203, Seer - Berserk: The engines blocked the center and castled in opposite directions. After exchanging queens Berserk doubled rooks on the c file, then traded a rook for a bishop and the game reached a RRN vs RBN position with black two pawns up. The engines cleared the pawns on the king side and Berserk created a passer in the center. The engines shuffled for a while, Berserk went wrong somewhere and Seer managed to force a piece exchange that left a R vs B ending. The white pieces were stronger, Seer slowly captured pawns and the game ended in a tablebase win. There were two white wins in this game pair.

game 205, Stockfish - RubiChess: The engines castled in opposite directions, opened the f file and blocked the center. Stockfish thought RubiChess played inaccurately evals started to increase. Stockfish declined a bishop for rook exchange and kept the center blocked. The engines exchanged more pieces, then RubiChess gave a pawn and gave Stockfish an advanced passer. Stockfish saw the win, it won a rook for the passer and the game reached a RBB vs BN position. RubiChess lost more material and was mated.

game 206, Leela - Seer: The engines blocked the center and played mostly behind their pawn lines. After exchanging a few minor pieces the engines exchanged queens, then stabilized the pawns. Seer had a pawn line across the board, confident in its defense its eval was below 1. Leela was confident it was winning with a high eval. For a long time the engines shuffled, on move 55 Seer probably blundered, Leela gave a pawn and started to attack the queen side. It captured a pawn and created a passer, Seer captured the passer but Leela created another and the game reached a RRB vs RRB position. Seer lost a bishop for the passer, both engines created more passers but Seer wasn't fast enough. Leela gave a rook, queened and mated.

Standings with 3 rounds to go: Stockfish +19, Leela +16, Berserk +3, KomodoDragon +2, Ethereal -6,  Seer -8, RubiChess -10, Stoofvlees -16. After beating Leela for the first and only time in the division Stockfish is almost certain to finish first, it is 1.5 points ahead of Leela with 3 games left. Berserk still has a small advantage over KomodoDragon. They drew their final game against each other, Berserk lost to Seer and KomodoDragon only drew against Stoofvlees. Ethereal has a 1 point advantage over Seer, which has a 1 point advantage against RubiChess, it is likely that the order will stay like this and the RubiChess will relegate.

game 213, Stockfish - Seer: The center was blocked and there were no exchanges after the start. Stockfish had more space, on move 31 the engines exchanged minor pieces and Stockfish captured a rook for a bishop. The first pawn exchange was on move 39, evals started to increase only after queens were exchanged on move 48. Seer sent a knight forward to capture a pawn, it created a passer but the knight was trapped. In a series of exchanges Stockfish traded a rook for two minors and the game reached a RBN vs RN position. Stockfish captured the black passer and exchanged rooks, Seer trie to protect its pawns but its king got trapped in the corner and mate followed.

game 215, Leela - Ethereal: The engines exchanged minor pieces and Leela captured an early pawn on the queen side. Leela's eval increased in a closed position, it slowly pushed its a pawn until it became a passer. On the king side Ethereal pushed pawns and exposed the white king, it captured two pawns and created connected passers. Leela was confident it can deal with this threat, and Ethereal's eval also started to increase. All pieces moved to the king side, Leela kept its king safe and then exchanged queens and reduced to a RRN vs RRB position. Leela added a second passer on the queen side, Ethereal lost a rook for one passer. It pushed its passers but Leela was ready for them, Leela captured both passers and also captured the second black rook for its second passer. The game ended in a tablebase win.

There is no change in the gaps between engines except that Seer is only 0.5 points ahead of RubiChess. Berserk only drew as white against Stoofvlees, keeping KomodoDragon's chances of catching up to third place.

game 219, Ethereal - RubiChess: Ethereal castled long and RubiChess kept its king in the center. RubiChess tried to attack the queen side and it captured a pawn in the center to create a passer. Ethereal regained the pawn and opened the center, with doubled rook on the d file threatening mate on the back rank. In a series of exchanges the engines reduced to a QBB vs QBN position, RubiChess was a pawn up and the white king was completely exposed but evals were in white's favor. Ethereal chased the black king and regained the pawn to create a passer on the king side. RubiChess gave its bishop for pawns to get rid of the passer. The white pieces attacked the black king, Ethereal forced a queen exchange and the game ended in a tablebase win.

game 220, KomodoDragon - Seer: The engines castled in opposite directions, KomodoDragon pushed pawns on the king side and managed to open the f file. After a series of exchanges the game reached a RRB vs RRN position with white a pawn up. KomodoDragon had a passer in the center, after exchanging a pair of rooks Seer regained the pawn, then it captured the white passer but lost its knight. Seer lost more material, it allowed a queening and was mated.

KomodoDragon is tied with Berserk in 3rd place, though Berserk has a head to head tiebreak advantage. Ethereal is safe in 5th place, Seer is still 0.5 points ahead of RubiChess before the last round.

game 221, Stockfish - KomodoDragon: Stockfish created an early passer on the queen side through an exchange. KomodoDragon captured the passer and Stockfish created a pawn majority on the king side. KomodoDragon gave a rook for a knight to capture one pawn but Stockfish still created an advanced passer facing the black king. Stockfish cleared the black pawns on the queen side and created another passer there, the game reached a QRB vs QBN position. After exchanging queens Stockfish saw the mate, KomodoDragon lost more material and after queening Stockfish mated.

Berserk secured 3rd place after KomodoDragon lost its last game, then is held a draw against Leela and didn't need the tiebreak. RubiChess only drew against Stoofvlees and finished 7th.

Featured game: Stockfish - Leela 
game 197

Stockfish pushed pawns on the king side and kept its king uncastled in the center. Stockfish captured a pawn in the center, then another on the king side, it was prepared for Leela forking king and rook with a knight. Stockfish lost the rook and didn't try to recapture, instead it attacked the black king though it was down a rook for a while. The black king was exposed and Leela surrounded it with pieces.

Leela gave material back and in a series of exchanges the engines reduced to a queen ending. Leela's eval was much lower than Stockfish's and it drifted down for a long time. After trading pawns Stockfish was a pawn up with a passer. Stockfish saw a win from a mile away while Leela's eval was below 1. 

The white king moved forward and after a while so did the passer. On move 75 Stockfish forced a queen exchange, then it queened the passer and the game ended in a tablebase win.

Season 26 premier division, after RR6

Standings after RR6

Stockfish is leading in front of Leela, it won 5 game pairs in the third DRR and Leela only 4. Surprisingly Stockfish drew against Stoofvlees for the second time. KomodoDragon got close to Berserk after beating it in their direct match for the first time. Berserk won the previous two matches. Both Berserk and KomodoDragon had a weak DRR with only 1 game pair win against other lower ranking engines. 

Interesting games

game 116, KomodoDragon - Ethereal: The engines castled in opposite directions, KomodoDragon pushed pawns on the king side and placed a pawn on h6. Ethereal tried to attack on the queen side, the engines traded a rook for two minors and then exchanged queens. Ethereal had 3 connected passers on the king side, in a series of exchanges the engines reduced to a BN vs R position and KomodoDragon created connected passers on the queen side. KomodoDragon managed to block the black passers, the engines traded one pair of passers but Ethereal couldn't stop the remaining white pawns. KomodoDragon queened and mated.

game 117, Stockfish - Ethereal: The center was blocked, Ethereal pushed pawns on the king side and Stockfish thought that was a bad idea. Stockfish gave a pawn and a rook for a bishop, then used threats on the black king and queen to equalize and reduce to a RBN vs RBN position. Stockfish's pieces were better, it captured a pawn and the exchanged down to a knight ending. Stockfish captued more pawns and created passers, then queened and mated.

game 118, Stoofvlees - KomodoDragon: The center was blocked, there were a few exchanges after the start and both kings walked to the king side without castling. Stoofvlees created a passer on the king side, the pawns stablized and the engines shuffled for a long time. On move 57 KomodoDragon let Stoofvlees push the passer, after a minor piece exchange Stoofvlees pushed it to h7. After another long shuffle Stoofvlees attacked from the king side. It lost its passer and the game reached a RB vs RN position but its pieces and pawns were much netter. Stoofvlees captured a pawn and trapped the black knight, KomodoDragon lost more material and the game ended in a tablebase win.

game 120, Leela - RubiChess: There were a few pawn and minor piece exchanges after the start, both engines castled long. Leela's eval was high although the engines seemed to shuffle for a while. RubiChess pushed the h pawn, it became a passer but then Leela captured it and exchanged a pair of rooks. The white king walked to the king side, then Leela gave a knight for 3 pawns and reduced to a RB vs RBN position. Leela pushed a passer forward, RubiChess exchanged pieces but couldn't stop the passer. Leela queened and mated.

game 123, KomodoDragon - Berserk: The engines castled in opposite directions, all pieces were on the board and the d file was open. KomodoDragon pushed pawns on the king side, after move 22 the engines exchanged a few pieces. Berserk captured a pawn and exchanged queens, giving KomodoDragon a passer on the queen side in a RBN vs RNN position. KomodoDragon managed to get the pawn back, Berserk captured the passer but KomodoDragon created another. The game reached a rook ending, KomodoDragon pushed the passer with its king supporting. Berserk couldn't prevent a queening, the game ended in a tablebase win. 

game 130, KomodoDragon - RubiChess: KomodoDragon was up a pawn from the start with a passer on g7. RubiChess equalized material and captured the passer, KomodoDragon created another and pushed it to h7. RubiChess attacked the white king and for a while thought that was enough as a counter. KomodoDragon kept its exposed king safe and captured a knight for a pawn. RubiChess captured the white passer, KomodoDragon captured more pawns and created another passer on the king side. The game reached a RN vs R position, KomodoDragon protected its last pawn and reduced to a tablebase win.

game 132, Stoofvlees - Berserk: The center was blocked and the engines opened the c file, Stoofvlees went a pawn up and created a passer on the queen side. Without any exchanges Stoofvlees slowly moved all its pieces to the king side, then started to exchange pawns and pieces from move 39. Berserk captured the passer on the queen side, Stoofvlees gave a knight for pawns to expose the black king and create passers on the king side. Stoofvlees captured back a knight and was two pawns up in a RRB vs RRB position. It pushed passers on the king side, Berserk lost material and the game ended in a tablebase win. 

game 133, Stockfish - Berserk: The engines castled in opposite directions and gradually exchanged pieces. The game reached a QRB vs QRB position, Berserk had a passer in the center but the black king was exposed. Stockfish used checks to capture a pawn and create a passer on the king side. Stockfish used a queen exchange to create another passer, Berserk captured one but the other was on the 7th rank. Berserk lost material and the game reached a tablebase win.

game 137, KomodoDragon - Stockfish: See featured game below.

Standings after RR5: Stockfish +12, Leela +11, KomodoDragon +1, Berserk 0, Seer -3, Ethereal -5, RubiChess -7, Stoofvlees -9. Stockfish has a small lead at top, it only drew as white against Stoofvlees  and won as black (with bias) against KomodoDragon. Leela drew as black (with bias) against Berserk and drew as white against KomodoDragon. KomodoDragon is in third place after gaining 2 full points on Berserk in RR5, including a direct win in their game. Both KomodoDragon and Berserk lost against Stoofvlees this RR. 

game 142, Berserk - RubiChess: There were only a few exchanges after the start, the engines exchanged a pair of bishops and then traded a pair of pawns, Berserk created a passer on the queen side. Berserk pushed the passer to the 5th rank, RubiChess captured a pawn and exchanged queens. Berserk regained the pawn and reduced to a RNN vs RR position, RubiChess captured the white passer but Berserk had another on the king side. Berserk slowly pushed the passer to the 7th rank, RubiChess lost a rook for the passer and the game ended in a tablebase win.

game 143, Stoofvlees - Seer: Stoofvlees gave a knight for 3 pawns and cleared the queen side black pawns. Stoofvlees captured another pawn but then evals turned negative as the engines reduced to a R vs RB ending with 4 white pawns and 1 black. Stoovlees chose the wrong king move and Seer pushed its pawn forward faster than the white pawns. Stoofvlees lost its rook for the pawn and the black pieces were on time to stop the white pawns. The game ended in a tablebase win. 

game 144, Ethereal - KomodoDragon: The engines castled in opposite directions, Ethereal pushed pawns on the king side, gave a pawn and opened the h file. The white queen moved forward and attacked the black king, in a series of exchanges the queens were exchanged and Ethereal captured a rook for a knight. KomodoDragon captured a pawn and created a doubled passer on the king side ,the engines shuffled and traded pawns for a while. After move 53 Ethereal created connected passers on the queen side, then it managed to trap and capture a knight. The game reached a RRB vs RB position, KomodoDragon lost more material and was mated. There were two white wins in this game pair.

game 149, Stockfish - RubiChess: The engines castled in opposite directions, after exchanging all rooks Stockfish pushed pawns on the king side and opened the h file. The engines exchanged queens and the game reached a BNN vs BNN position with white a pawn up. Both kings moved to the center and the bishops were exchanged, on move 47 Stockfish created a passer on the king side. RubiChess blocked the passer and the white king for a while, after exchanging a pair of knights Stockfish saw the win. RubiChess lost a knight for the passer, Stockfish created another and queened to mate.

game 150, Leela - Seer: There were a few pawn and minor piece exchanges after the start, on move 28 the engines opened the f file. Seer captured a pawn and Leela attacked on the king side. Leela managed to place a protected bishop on d6, Seer gave a rook to capture it and another pawn. The game reached a  RR vs RN position, Seer was two pawns up with a passer in the center. The white pieces were more effective, Leela kept the black king confined on the king side. Leela captured the black passer, then captured two more pawns on the queen side and created a passer. Seer lost its knight, the black king was trapped and the game ended in mate.

game 157, Stockfish - Seer: Seer was up a pawn with a passer on the queen side but its king moved without castling and blocked the king side rook. Seer tried to develop the rook through the h file but it was still restricted and not effective. After some shuffling Seer captured another pawn and connected a passer, while Stockfish placed a rook on the 7th rank. Seer pushed its passers and gave a rook for a knight, after more exchanges the game reached a RR vs R position with black 4 pawns up. Stockfish captured pawns and saw the win, it managed to control the black pawns, eventually it queened and mated.

game 158, RubiChess - KomodoDragon: RubiChess was up a pawn with a passer on g7 from the start. KomodoDragon captured the passer and RubiChess created another on the h file. After exchanging queens the engines traded pawns on the queen side, the game reached a RRN vs RRN position with white two pawns up and with passers on both sides of the board. KomodoDragon captured the passer on the king side but couldn't stop the passer on the queen side. RubiChess queened and mated. There were two white wins in this game pair. 

game 159, Leela - Ethereal: There was one minor piece exchange after the start, all pawns were on the board and both kings remained uncastled. Leela developed its king side rook through the h file, pawn lines blocked the center and queen side with a small hole on the g file. Leela's eval was high though the engines seemed to shuffle. On move 48 Leela opened the g file and exchanged a pair of rooks, after exchanging the remaining rooks Leela created connected passers in the center on move 66. Ethereal lost material for one passer, the game reached a Q vs BB position. Leela gained more material and mated.

game 164, KomodoDragon - Seer: KomodoDragon castled long despite the weak pawn cover there. It then pushed pawns on the king side, giving two pawns and opening the g file. KomodoDragon doubled rooks on the h file, Seer exchanged queens to avoid mate. KomodoDragon captured pawns and moved a its rooks to the 7th rank, Seer exchanged a pair of rooks and the game reached a RN vs RN position with white two pawns up. KomodoDragon slowly pushed connected passers on the queen side, then trapped the black king and mated.

Featured game: KomodoDragon - Stockfish
game 137

The game started with a black bias, Stockfish was a pawn up and the white king moved without castling. KomodoDragon regained the pawn, its king walked to the queen side and trapped the rook there. Stockfish captured a pawn and opened the a file for the white rook the . KomodoDragon tried to create some pressure on the king side with major pieces, Stockfish exchanged a pair of rooks and the game reached a QRB vs QRB position. 

The white king moved to free the rook. The engines shuffled for a while, KomodoDragon's eval remained low but Stockfish's eval increased steadily. On move 54 the engines exchanged rooks, KomodoDragon started to see the problem. Stockfish exchanged pawns on the king side and created a passer. 

The engines traded pawns and Stockfish connected a second passer, KomodoDragon created passers on the queen side but they weren't fast enough. KomodoDragon lost the bishop for one passer and the game ended in a tablebase win.