Season 24 premier division, after RR6

Standings after RR6

Stockfish increased its lead to 1.5 points after a perfect score of 7/7 game pair wins in DRR3. Leela is in second place after winning 6/7 game pairs. KomodoDragon is in third, already 3 points behind Leela, it lost to the two leaders and also drew one of the game pairs against the bottom 5.

The bottom 5 engines' standings seems to be stable with at least 1.5 points separating them. Ethereal is in 5th place after beating Stoofvlees, it closed the gap to Berserk by 0.5 points in DRR3 but with only one more DRR to play it is likely Berserk will finish 4th. 

Also in DRR3: SlowChess won its first game pair, and there were no double win results in all game pairs.

Interesting games

game 117, Stockfish - Stoofvlees: Stoofvlees did not castle its king, and when Stockfish opened the f file the black king was stuck in the center. Stoofvlees captured two pawns and exposed the white king, Stockfish attacked quickly and Stoofvlees was too busy defending. The black king ran to the queen side, Stockfish moved queen and rook to the back rank, gained material and mated.

game 118, Ethereal - SlowChess: The engines castled in opposite directions, all pawns remained on the board and there were only a few minor piece exchanges after the start. Ethereal pushed pawns on the king side, one reached g6, its eval increased steadily. The first pawn exchange was on move 35, Ethereal opened the center and went a pawn up. In a QRB vs QRN position Ethereal captured another pawn, after exchanging queens Ethereal captured the knight. Ethereal gave material and reduced to a 7-man win, then played it for 30 more moves before adjudication.

game 119, Leela - Koivisto: Both engines castled long, most minor pieces were exchanged early and Leela went a pawn up with a passer in the center. Koivisto captured the passer and two more pawns but lost a bishop, the game reached a RN vs R position. Leela gave back the knight and reduced to a won rook ending. 

game 120, KomodoDragon - Berserk: Exchanges opened both the b file and the f file, KomodoDragon already castled short and it placed a rook on each open file. Berserk chose to castle long, then tried to keep its king safe from attack. After a while all rooks were gone, the game reached a QNN vs QBN position with white a pawn up. KomodoDragon had a passer in the center that had to be watched, after exchanging queens KomodoDragon captured another pawn. The black king walked to the center, KomodoDragon exchanged a pair of knights and captured a third pawn on the queen side. Berserk couldn't block all the white passers advancing, game over.

game 125, Stockfish - Ethereal: Stockfish castled long and pushed pawns on the king side, Ethereal castled short anyway. Ethereal captured a pawn on the king side, another reached h6, the white queen moved forward on the queen side and regained the pawn. After a while Stockfish captured another pawn on the queen side and created connected passers. The game reached a RB vs RN position and Stockfish pushed a passer to the 7th rank. Ethereal gave its rook to capture the two white passers on the queen side, Stockfish created one on the king side to win. 

game 126, Leela - Stoofvlees: Most minor pieces were exchanged early, evals were stable after the start. Leela delayed its castling, choosing to castle long in the end. Evals increased very slowly and the game reached a QRB vs QRN position. Both kings were exposed, for a while Leela hid its king behind a black passer. After Leela captured the passer Stoofvlees thought it was holding and its eval dropped, only to jump back up a few moves later. Leela cleared the center and threatened mate along the long diagonal. Stoofvlees gave a rook for a bishop to remove the threat, then was mated on the back rank. 

game 127, KomodoDragon - SlowChess: KomodoDragon castled long and pushed pawns on the king side, SlowChess chose not to castle its king, there were holes in the pawn support on both sides. KomodoDragon gave a rook for a bishop and opened the d file, SlowChess gave the material back and tried to weaken the white king's defense. SlowChess was a pawn up in a QRB vs QRB position, however the black king was exposed. KomodoDragon used attacks on the black king and pieces to capture pawns and then reduced to a winning king and pawns ending.

game 133, Stockfish - Leela: see featured game below.

game 135, Berserk - Stoofvlees: There were many early exchanges and the game reached a QRN vs QRN position. Evals were stable though Berserk went a pawn up and then created a passer on the queen side. On move 39 Berserk's eval started to increase, it took Stoofvlees 5 moves and 9 minutes thinking to see the problem. Berserk pushed the passer to the 7th rank, Stoofvlees captured it but Berserk captured pawns on the king side and reduced to a queen ending two pawns up. The game ended in a tablebase win. 

game 138, Stoofvlees - Koivisto: Stoofvlees was up a pawn with a passer on the queen side from the start, its king walked to the king side without castling. Koivisto regained the pawn but evals increased steadily. Stoofvlees gave a pawn and created a passer on the king side, after a series of exchanges the game reached a RBN vs RR position. Koivisto captured the passer on the king side, Stoofvlees pushed the one on the queen side to the 7th rank. After a while Stoofvlees exchanged a pair of rooks, Koivisto captured the passer but Stoofvlees captured the remaining black pawns for the knight. Stoofvlees was three pawns up in a B vs R ending, a 7-man win that was adjudicated 25 moves later.

game 140, Leela - KomodoDragon: There were a few exchanges after the start, Leela created an advanced passer in the center. Evals remained stable, pawn exchanges opened the board and by move 42 all the rooks were gone. On move 47 evals started to increase as the engines played out a PV agreement, the game reached a BBN vs BNN position. KomodoDragon was a pawn up but Leela had a bishop pair and the passer. KomodoDragon gave a knight to stop the passer on the 7rh rank, it captured all the white pawns but one. Leela kept its one pawn safe and gradually captured black pawns. The white pawn became a passer and the white king came forward to support it. Eventually both engines queened, Leela was first and it immediately mated. 

Standings after RR5: Stockfish +13, Leela +11, KomodoDragon +7, Berserk +1, Ethereal -4, Stoofvlees -6, Koivisto -9, SlowChess -13. Stockfish beat Leela and Leela beat KomodoDragon, it should be interesting to see what happens in the reverse games. KomodoDragon only drew against Ethereal as white, there is little chance it can catch up to the leaders. There was almost no change in the bottom 5 with only 3/10 decisive games within this group.

game 141, Stockfish - KomodoDragon: The center was blocked, there was one minor piece exchange after the start and all pawns were on the board. Stockfish kept its king in the center while KomodoDragon walked its king to the queen side. After move 20 there were a few pawn exchanges, the a file opened and evals started to increase slowly. KomodoDragon moved its king back to the center, it went a pawn up after exchanging queens, creating a passer on the king side. The black king couldn't find a safe spot, it was almost trapped when Stockfish placed a knight on c6, KomodoDragon gave a knight for a pawn to get rid of it. In a RBB vs RN position Stockfish captured pawns, then queened a passer and reduced to a tablebase win.

game 142, Leela - Berserk: Leela's eval jumped on move 9, the engines exchanged all bishops and Leela pushed pawns in the center. Berserk went a pawn up and the white king was uncastled but Leela created a passer in the center. Berserk gave a rook for a knight to block the white passer's advance, the game reached a RRN vs RNN position. Berserk had connected passers on the king side but they were too slow, Leela pushed its passer and Berserk lost a knight to stop it. Leela captured pawns and promoted another passer (to a rook), game over. 

game 144, Stoofvlees - SlowChess: Evals were stable with only a few minor piece exchanges after the start, on move 24 SlowChess went a pawn up yet evals started to increase slowly. The engines opened the queen side, the white pieces were more active, Stoofvlees tried to find a way to attack. Stoofvlees regained the pawn and exchanged a pair of rooks, after exchanging queens only RBB vs RBN were left. Stoofvlees pushed a passer to the 7th rank and SlowChess lost a knight to stop it. The engines traded pawns and a pair of bishops, then Stoofvlees promoted its last pawn to a rook and won.

game 149, Stockfish - Berserk: There were only a few exchanges after the start, the engines blocked the center and the queen side but there was an opening on the king side. Stockfish had a strong LS bishop and it also pushed a passer to h6, blocked by the black king. The white king walked to the queen side and Stockfish increased the pressure on the king side. Stockfish gave a pawn to disrupt the black pawn structure on the queen side, after some preparations the engines exchanged a few pieces including the white LS bishop. The game reached a RBN vs RBN position, Stockfish used the DS bishop to capture pawns on the queen side and created connected passers. Berserk couldn't stop the passers, Stockfish queened twice to win. 

game 150, KomodoDragon - Koivisto: KomodoDragon kept its king in the center and pushed the g pawn towards the black king. Most minor pieces were exchanged and KomodoDragon moved its major pieces to the king side. Koivisto exchanged pieces to remove the danger to its king, the game reached a B vs N ending with white a pawn up. KomodoDragon traded pawns and reduced to a winning 7-man position, the game was adjudicated 25 moves later.

game 151, Leela - SlowChess: There were only a few exchanges after the start and Leela went a pawn up. Evals started to increase on move 23, the engines opened the g file and SlowChess tried to attack the white king. Leela exchanged pieces until only QN vs QB remained and for a long while the engines shuffled. On move 67 SlowChess moved a pawn and evals started to increase again. The shuffle could have continued but I am certain Leela would have found a way to improve eventually. Leela managed to create a passer, SlowChess captured it and exchanged the minor pieces. Leela created another passer and that was enough to win the queen ending. 

game 152, Ethereal - Stoofvlees: Ethereal moved its queen forward and captured a pawn, its eval increased steadily while Stoofvlees' eval was stable. On move 25 Stoofvlees realized it was in trouble, it tried to attack the white king. Stoofvlees opened the king side but lost a knight, Ethereal kept its king safe and countered with an attack on the black king. Ethereal gave material back and mated on the back rank.

game 157, Stockfish - Koivisto: There were no exchanges after the start, the center was blocked and evals were stable. After move 20 a pair of pawns and a pair of minor pieces were traded, Stockfish created a passer on the king side and pushed it to the 6th rank. Evals started to increase, the white queen moved forward on the king side and the white rooks focused on the queen side. Stockfish moved its king forward to the king side and pushed the passer to the 7th rank, Koivisto gave a rook for a knight but the pressure continued to increase. Koivisto gave a knight for a pawn in desperation, Stockfish was up a rook. It captured all the black pieces, trapped the black king on the back rank and mated.

game 158, Berserk - SlowChess: The center was blocked and the engines castled in opposite directions. There were only a few exchanges after the start, on move 28 SlowChess gave a pawn to open the queen side. Evals increased slowly, all bishops were exchanged and Berserk moved its pieces to the king side while SlowChess focused on the queen side. After a series of exchanges the game reached a RNN vs RNN position, Berserk was a pawn up with passers in the center and the queen side. Berserk pushed a passer to the 7th ranked where it was captured, but Berserk captured a trapped knight. The game ended in a tablebase win. 

game 159, KomodoDragon - Stoofvlees: The center was blocked and there were only a few exchanges after the start. The engines opened the a file and evals started to increase. Stoofvlees moved a rook forward on the queen side and was later joined by the black queen. KomodoDragon used minor pieces to trap the rook. Stoofvlees sacrificed a knight to expose the white king, KomodoDragon captured the black rook for a knight, the net effect of the exchanges was that KomodoDragon was up by a knight. Stoofvlees tried to threaten the white king, but its own king had to run forward as well. KomodoDragon gained material, Stoofvlees gave up and was mated quickly.

game 160, Leela - Ethereal: Leela's eval was high from the start, it was over 2 very early. The black queen move forward and the queen side opened, however Leela chose to castle long after the black queen moved away. Ethereal moved its king without castling, the white rooks were dominant in the open center files. There was a long series of exchanges in a long PV agreement that led to a QR vs RRN position. The engines traded pawns until each had one pawn left, Ethereal surrounded its king by pieces and tried to hold. Leela pushed its pawn safely to the 7th rank, eventually Ethereal gave a rook to stop it. This left a 7-man win that was played out for another 15 moves.

game 164, SlowChess - Koivisto: There were a few exchanges after the start, SlowChess had a space advantage. On move 24 evals started to increase. SlowChess gave two pawns and exposed its king, but it also threatened the black king that was almost trapped. Koivisto exchanged pieces and reduced to a RRN vs RNN position, its king still in danger. SlowChess created a passer on the queen side and pushed it to the 6th rank. Koivisto pushed its own passer to the 3rd rank, SlowChess gave a rook for a knight and stopped the black passer. SlowChess captured more black pawns, Koivisto lost material but couldn't stop a queening, game over. 

game 165, Stockfish - SlowChess: Stockfish was up a pawn with a passer on the queen side from the start. Evals increased slowly as the engines traded pieces and pawns, then jumped after the queens were off the board. The game reached a RBN vs RBB position with black a pawn up, Stockfish traded its passer with a black passer and captured a bishop. The king side was blocked, Stockfish reduced to a knight vs pawns ending, both engines saw the mate 25 moves forward.

Featured game: Stockfish - Leela
game 133

There were a few exchanges after the start and evals were stable. The engines played out a long PV agreement that opened the center, by exchanging a pair of rooks Stockfish created and advanced passer on d6. 

Stockfish's eval started to increase slowly, Leela still thought it was safe. Stockfish followed Leela's PV and the moves seemed innocent enough, a few pawns pushed by Leela. Then on move 40 Leela thought for 6 minutes and its eval jumped over 2.5. It was really not clear what changed, except perhaps that Stockfish activated its LS bishop. For a minute both engines saw a long PV that ended in a QB vs RBN position, but they diverged to another plan. Leela's pieces became more passive and Stockfish kept finding targets to attack. After more than 25 moves Stockfish went a pawn up in a QRB vs QRB position, driving the black king to the center.

Stockfish captured a second pawn and reduced to an opposite color bishops ending. The black king guarded the passer on d6, protected by the white bishop. The white king moved forward on the queen side and captured more pawns. There was no way to prevent a queening and mate.

Season 24 premier division, after RR4

Standings after RR4

In the second DRR the top3 engines won 13/15 game pairs against the bottom 5, Stockfish and Leela had a perfect record, KomodoDragon drew twice. Together with the fact that Stockfish Beat KomodoDragon this explains why KomodoDragon is 1.5 points behind Leela and Stockfish is leading 0.5 points ahead of Leela.

Berserk is still safely in 4th place, with 3 game pair wins within the bottom 5. Ethereal and Stoofvlees improved their standings with positive scores within the bottom 5, Koivisto and SlowChess had negative scores within the bottom 5 and they are currently in the relegation zone.

Interesting games

game 61, Stockfish - Stoofvlees: Stockfish's eval increased from the start, it sacrificed a knight for two pawns and exposed the black king in the center. Stockfish then captured a rook for a bishop, the engines reduced to a RR vs RBN position with white 3 pawns up. After some preparations Stockfish exchanged a pair of rooks, then created passers on the king side. Stoofvlees captured one passer, Stockfish lost some material but queened another passer to win.

game 62, Ethereal - SlowChess: SlowChess was slow developing its king side pieces, Ethereal gave a rook for a bishop and created a passer on the queen side. By the time SlowChess castled its king Ethereal pushed the passer to the 7th rank and SlowChess had to use a rook to block. SlowChess gave back a rook for a bishop to capture the passer, Ethereal was two pawns up in a QRN vs QRB position. After exchanging queens Ethereal trapped the black king on the back rank and captured the remaining black pawns. The game ended in a tablebase win.

game 63, Leela - Koivisto: There were many minor piece exchanges after the start, both kings moved without castling. Evals increased quickly, Koivisto took longer to connect the rooks and Leela had a space advantage. After exchanging queens only RRN vs RRB remained, Leela gave a pawn and opened the king side. Leela placed a rook on the 7th rank and Koivisto tried to protect its king and pawns. Leela exchanged a pair of rooks and created advanced passers, Koivisto lost material and was mated.

game 68, Stoofvlees - Ethereal: Stoofvlees gave a pawn and hid its king behind a black pawn on h3. The king side opened, after a few minor piece exchanges Stoofvlees captured the black h pawn. The game reached a RRB vs RRB position, Stoofvlees controlled the open h file. On the queen side Stoofvlees created an advanced passer, after exchanging a pair of rooks it placed a rook on the 7th rank. Ethereal captured the passer while the white king moved forward. Stoofvlees went two pawns up and the game ended in a tablebase win. 

game 69, Stockfish - Ethereal: Stockfish exchanged both its bishops for knights after the start and the engines castled in opposite directions. Evals were stable and the engines mostly shuffled for a while, on move 36 Stockfish traded Q for RR and evals increased a little. After some more shuffling Ethereal seemed to blunder and give Stockfish a pawn on move 57, Ethereal saw the problem 3 moves later and it gave a bishop to capture a passer. Stockfish reduced to a NN vs B position, it captured pawns, then queened and mated.

game 70, Leela - Stoofvlees: The engines castled in opposite directions and Leela opened a file in the center. Evals were high and increasing, Leela captured pawns and the queen side opened. Stoofvlees gave a rook for a bishop, its compensation for the material was an attack on the exposed white king. However, Leela kept its king safe, gave back material and reduced to a RN vs RB position. Leela was only a pawn up and Stoofvlees pushed a passer to the 2nd rank, but Leela queened a passer first, game over.

game 72, Berserk - Koivisto: There were no exchanges after the start, Berserk moved its king forward to the queen side without castling. The first pawn exchange was on move 22, a second opened the a file. On move 39 the engines exchanged a pair of rooks followed by a long shuffle. On move 82 Berserk moved a pawn on the king side and evals started to increase. Koivisto reacted with a knight sacrifice that exposed the white king and attacked. Berserk kept its king safe, after exchanging queens the attack was over. Koivisto tried to push a passer, Berserk captured the passer, gained more material and won.

game 78, KomodoDragon - Ethereal: There was one pawn exchange that opened a file in the center, other than that the engines mostly shuffled for a long time with stable evals. On move 39 the engines exchanged a pair of rooks, a minor piece exchange followed and evals started to increase. On move 57 KomodoDragon sacrificed a knight for two pawns and reduced to a BB vs BNN position. Ethereal did not have a DS bishop, this allowed KomodoDragon to capture two more pawns and create 4 connected passers on the queen side. Ethereal had to give material to stop the passers and was soon mated.

game 79, Berserk - Stoofvlees: There were many early exchanges and the game reached a QRR vs QRR position. Stoofvlees was a pawn up but its king was in the center and Berserk managed to place a pawn on e7 to trap it. Stoofvlees realized it was in trouble much too late, when it captured the e7 pawn Berserk pinned the black queen and captured it for a rook. Mate was a matter of time.

game 80, Koivisto - SlowChess: Evals increased quickly from the start, Koivisto controlled the open c file and its two bishops were strong in the center. SlowChess played waiting moves, Koivisto reduced to a QRR vs QRR position with the black king exposed. SlowChess lost its queen for a rook and its king was in a mating net, game over.

game 82, Stoofvlees - Koivisto: There were no exchanges after the start and the engines castled in opposite directions. Stoofvlees made an opening on the queen side with a pawn exchange, then doubled rooks facing the black king. After a few minor piece exchanges Koivisto captured a pawn and gave a knight for another pawn. After a series of exchanges the game reached a RN vs R position, Stoofvlees was patient and it managed to reduce to a winning rook ending.

game 83, Ethereal - Berserk: There was one exchange of a pair of bishops after the start, other than that the engines mostly shuffled. After move 32 a few pawn exchanges opened the queen side, Ethereal went a pawn up but evals were stable. Ethereal thought Berserk made a mistake on move 44, a few moves later Berserk's eval jumped as well. Ethereal gave a bishop and opened the king side, the black king ran and Ethereal captured a rook. The game reached a RN vs NN position, progress was slow and Ethereal shuffled a lot but eventually it captured a pawn and created a passer. Berserk couldn't stop the passer, the game ended in a tablebase win.

Standings after RR3: Leela Stockfish +6, KomodoDragon +5, Berserk +1, Stoofvlees -3, Koivisto Ethereal -4, SlowChess -7. KomodoDragon failed to win as white twice against a bottom5 engine, it is likely to stay in 3rd place after RR4 as well. Berserk is still firmly in 4th place though it lost to Ethereal. Stoofvlees beat both Ethereal and Koivisto, in the previous DRR it lost the reverse games, can it hold a draw this time?

game 85, Stockfish - KomodoDragon: see featured game below.

game 86, Leela - Berserk: For a while evals were stable, there were no piece exchanges after the start. Leela's eval started to increase after move 20, a series of exchanges reduced to a RRB vs RBB position. Leela created a passer on the queen side, the engines traded a pair of bishops and Berserk went a pawn up. Berserk blocked the white passer on the 6th rank, it tried to counter on the king side and created connected passers. Leela captured a pawn and created a second passer on the king side. A black passer was caught on the 2nd rank, Berserk couldn't stop the advancing white pawns and the game ended in a tablebase win.

game 87, Ethereal - Koivisto: The engines opened a file in the center with a pawn exchange, evals increased slowly though only a pair of rooks was exchanged until move 34. A series of exchanges reduced to a QBB vs QBN position with white a pawn up. Ethereal moved its queen to the 7th rank forcing Koivisto to defend. Both engines created passers, Ethereal hid its king behind a black pawn. After exchanging queens Ethereal captured the remaining black pawns, then used its passers to gain material and win.

game 88, Stoofvlees - SlowChess: An exchange half opened the g file yet the white king was safe from attack. SlowChess kept its king in the center, evals started to increase after Stoofvlees gave a pawn and further opened the queen side. After a few minor piece exchanges the g file opened, SlowChess finally decided to castle long and Stoofvlees regained the pawn. Stoofvlees moved a rook to the 7th rank, SlowChess gave a rook for a bishop and the game reached a R vs N ending. Stoofvlees pushed a passer forward, captured all the black pawns and the knight. The end was hilarious, SlowChess avoided a 6-man tablebase, Stoofvlees promoted 4 pawns - only the 4th to a queen - before forcing a tablebase win.

game 93, Stockfish - Berserk: The center was blocked, two pawn exchanges opened files on both sides. All pieces stayed on the board and evals increased slowly. On move 52 Stockfish captured a pawn and created a passer on the queen side. The engines started to exchange pieces while Stockfish pushed the passer forward, the game reached a RB vs BNN position. The white passer got to the 7th rank, Stockfish captured pawns and created two more passers. Berserk lost a bishop to stop one passer, Stockfish queened another to win.

game 94, KomodoDragon - Koivisto: KomodoDragon pushed pawns on the king side, its king was left without pawn support but evals increased slowly. KomodoDragon had a space advantage, for a while Koivisto played waiting moves and then exchanges opened a file in the center. KomodoDragon placed a knight on g6 and made threats on the g file, then in a QRN vs QRN position it created a supported passer on d6. KomodoDragon captured a pawn, then captured a black passer on the 3rd rank. Koivisto lost its knight for the white passer, KomodoDragon reduced to a winning king and pawns ending.

game 95, Leela - SlowChess: The engines castled in opposite directions, Leela thought SlowChess' move 13 was a blunder. Leela started an attack on the queen side slowly, moving its bishops out of the way and its king to the corner for safety. Then it exposed the black king, moved its queen forward and gave a rook for a knight. The black king was soon in a mating net, SlowChess gave material to delay and was soon mated.

game 96, Ethereal - Stoofvlees; The black king was stuck in the center, Ethereal gave a pawn and opened a file on the queen side. The white queen moved to the 7th rank with more pieces ready for an attack on the black king. Stoofvlees exchanged queens but still Ethereal had a rook on the 7th rank. Ethereal gave a rook for a bishop, only RBN vs RRB were left, still enough to chase the black king and mate. There were two white wins in this game pair. 

game 101, Stockfish - Koivisto: Koivisto was a pawn up with the engines castled in opposite directions, but evals increased slowly. Stockfish pushed pawns on the king side with one reaching h6, Koivisto  locked the pawn lines. Stockfish had strong bishops on the queen side, it gave a rook for a bishop and for a few moves it used pins and mate threats to arrange its pieces. A series of exchanges reduced to a RB vs N position. Koivisto had an advanced passer, Stockfish gave the bishop to capture it, it then gave the rook to queen a pawn and win.

game 102, Berserk - SlowChess: Berserk castled long, there were many exchanges after the start the opened the queen side and cleared most of the minor pieces. SlowChess castled short, Berserk was a pawn up, for a while the engines mostly shuffled as evals increased. Berserk captured another pawn and created connected passers on the queen side. Then Berserk reduced to a double rook ending and slowly pushed the passers forward supported by the white king. SlowChess lost both its rooks for the passers and was mated.

game 103, KomodoDragon - Stoofvlees: KomodoDragon castled long and pushed pawns on the king side. Stoofvlees had two knights there almost trapped, it decided to give one for a pawn and then castled short. Stoofvlees captured another pawn, giving the white major pieces more access to attack the black king. Stoofvlees tried to counter with threats on the white king but KomodoDragon was quicker, it gave a bishop and surrounded the black king with mate following.

game 104, Leela - Ethereal: The engines castled in opposite directions, the white queen moved forward on the king side. After a long series of exchanges the king side opened and only RRN vs RRN remained. There was a period of mostly shuffling and then Leela went a pawn up. Leela was very patient, first it exchanged a pair of rooks, then it created a passer with a pawn trade. Ethereal tried to delay and avoided piece exchanges, eventually Leela pushed the passer forward. It gave the rook and queened the passer, the game ended in a tablebase win.

game 109, Stockfish - SlowChess: The game started with the black king unable to castle after moving. Stockfish castled long, there were a few exchanges after the start and evals stayed stable. After opening the f file evals started to increase, the black king side rook was still stuck in the corner and SlowChess couldn't get it developed. Stockfish gave a pawn and focused its major pieces in the center. SlowChess freed its rook while Stockfish opened the center and moved a rook forward. Stockfish captured black pawns until there was only one left, SlowChess surrounded its king with pieces. Stockfish exchanged pieces until only B vs R remained with white 3 pawns up, a 7-man tablebase win that Stockfish continued to play for 35 more moves before adjudication.

game 111, Berserk - Ethereal: There were no exchanges after the start, the center was blocked, Ethereal castled long and Berserk walked its king to the king side. On move 28 Berserk gave a pawn on the king side, then the engines shuffled for a while. On move 41 Berserk regained the pawn and created a passer, evals started to increase. Berserk walked its king to the queen side, Ethereal started an attack with a bishop sacrifice. Ethereal managed to get two advanced passers facing the white king, Berserk defended its king and captured the passers, leaving it a rook for a knight up. Berserk pushed its passer slowly, Ethereal couldn't stop it and eventually Berserk gave a knight and queened, game over.  There were two white wins in this game pair. 

Featured game: Stockfish - KomodoDragon
game 85

Evals increased from the start, on the 3rd move after book Stockfish's eval was already over 2. Stockfish castled long and KomodoDragon moved its queen forward and captured a pawn. Stockfish used threats to the black queen to place a knight on d6, forcing the black king to move. Then Stockfish trapped and captured the black queen for a rook and a bishop. 

KomodoDragon captured another pawn and was two pawns up, it also managed to trade and get rid of the knight on d6. However, the white queen found a way through on the king side. It moved forward and Stockfish cleared all the black pawns on the king side. The engines were down to two pawns each,  all passers. 

Stockfish exchanged a pair of rooks and the game reached a QB vs RBN position. KomodoDragon tried to keep its king safe and its pieces protected, but eventually Stockfish captured a bishop and mated followed. 

Season 24 premier division, after RR2

Standings after RR2

The top 3 engines are back in their familiar position in the table, again dominating from the start. They won 12/15 game pairs against the rest of the field without loss. Stockfish won all its game pairs against weaker engines, KomodoDragon won 4 and Leela only 3. Leela also won a game pair against Stockfish, the reason all 3 engines are tied. 

Currently Berserk is in 4th place, this season this is significant since there will be a playoff stage for the 4 engines in the lead at the end of the premier division. 

SlowChess is last, it is the only engine in the bottom 5 with a negative score in games within the bottom 5. Ethereal is currently in 7th place but it is very early in the relegation race. I'm a bit surprised that Berserk has a better score that Koivisto and Ethereal, Koivisto was much better than Berserk in league 1, and Ethereal finished 4th in the premier division of season 23 where Berserk finished last. Berserk was updated after league 1, it appears that this update was significant.

Interesting games

game 4, SlowChess - Stoofvlees: The black queen moved forward to attack, a series of exchanges left SlowChess up by a rook while its king and king side rook were trapped in a corner. Stoofvlees' attack was not strong enough, SlowChess pushed a passer on the queen side and Stoofvlees lost another rook to stop it. SlowChess eliminated the threats near its king, after its king side rook was released the material advantage was too great and SlowChess mated.

game 5, Stockfish - Stoofvlees: There were many piece exchanges after the staTrt, evals started to increase and the game reached a RRB vs RRB position with a white rook on the 7th rank. Stockfish went a pawn up and exchanged a pair of rooks, its king was active in the center and it had a central passer. Stockfish had mate scores in its eval, the bishops were exchanged and the passer was unstoppable, game over.

game 6, Ethereal - SlowChess: Ethereal castled long, SlowChess tried to attack on the queen side and it left its king uncastled. Ethereal kept its king safe and pushed the black pieces back, SlowChess tried to find a safe spot for its king on the king side. Ethereal lined up its major pieces on the g file, then forced open the king side. In a QRB vs QRB position Ethereal chased the black king back to the center, then reduced to a won same color bishops ending a pawn up. 

game 7, Leela - Koivisto: Leela castled long, Koivisto pushed pawns on the queen side and opened the a file. The black king stayed in the center, Leela created a passer on the queen side and pushed it slowly forward until it reached the 7th rank. Koivisto tried to counter with pawns on the king side where it had a majority, but its pieces were busy defending. Leela created a second passer, it went a pawn up and exchanged a pair of rooks. In a QRB vs QRN position Leela pushed a second passer to the 7th rank, Koivisto couldn't stop a queening, game over.

game 8, KomodoDragon - Berserk: The engines castled in opposite directions, there were no pawn attacks and material was equal, KomodoDragon created a passer on the queen side. Evals started to increase after move 30, though Berserk created a passer on the king side. KomodoDragon went a pawn up, Berserk gave a bishop for two pawns to clear most of the pawns on the queen side. In a QRN vs QR position KomodoDragon attacked the black king and Berserk didn't have time to push passers forward. Both engines had mate score evals and the game ended in a tablebase win.

game 12, Stoofvlees - Ethereal: For a while it seemed that Ethereal equalized, evals were more or less stable until move 30. Stoofvlees had a pawn majority on the queen side with a pawn on a6, Ethereal used a bishop as a blocker. In a series of exchanges the engines reduced to an opposite color bishops ending, at first white was only one pawn up but due to the weak pawn structure Stoofvlees captured two more pawns. The black king was too far and the bishop had too much to defend. Stoofvlees gave back pawns but created passers on the king side and Ethereal had to give its bishop to avoid a queening. The game ended in a tablebase win.

game 13, Stockfish - Ethereal: Stockfish thought Ethereal's move 17 was weak, after Stockfish's response Ethereal's eval jumped as well. Ethereal captured a knight on the queen side but Stockfish attacked the black king with a bishop sacrifice. Ethereal gave back the material and exchanged pieces, the result of the attack was a RR vs RB position. Stockfish had a passer on either side of the board while Ethereal had a doubled passer. It took Stockfish more than 40 moves to pushed both its passers forward and to capture one black pawn, the game ended in a tablebase win.

game 14, Leela - Stoofvlees: Stoofvlees moved its king without castling and evals started to increase. Leela opened the center with a knight sacrifice for two pawns. For many moves Leela refused to exchange bishop for rook, instead it increased the pressure on the open d file. The engines traded queens and Leela moved both its rooks to the 7th rank, then used them to capture a rook and reduce to a RB vs NN position. Both engines had a passer, Leela queened first with check and a few moves later mated.

game 15, KomodoDragon - SlowChess: Evals were stable until move 40, the only pieces exchanged were a pair of bishops and a pair of rooks. SlowChess moved its bishop to e4, KomodoDragon thought that was a mistake and both evals jumped. Within a few moves all the white pieces were attacking, KomodoDragon captured the bishop and the game reached a QBN vs QN position. SlowChess delayed a little with checks but it was soon mated.

game 16, Berserk - Koivisto: Evals slowly increased after the start though material was equal. Berserk's main advantage was that it controlled an open file on the queen side. The white rook moved forward and after a while the white queen joined the rook, Koivisto could not force them away. Berserk managed to capture a bishop on the back rank, then the engines reduced to a QB vs Q position. Berserk captured two pawns, then exchanged queens to win. 

game 19, Stoofvlees - KomodoDragon: Evals were stable until move 35, KomodoDragon had a passer on the queen side and Stoofvlees had a pawn majority on the king side. Evals started to slowly increase as Stoofvlees created a passer on the king side, there were still many pieces on the board and all passers were blocked. The engines opened the queen side and the white queen moved forward, then on the king side Stoofvlees captured a pawn and connected a second passer. After exchanging queens KomodoDragon did not have enough strength to block the passers, Stoofvlees captured a knight and queened to win.

game 22, KomodoDragon - Ethereal: The engines castled in opposite directions, KomodoDragon gave two pawns and opened the king side. Ethereal had tripled pawns in the center, KomodoDragon doubled rooks on the e file and captured all three black pawns there. The game reached a rook ending with white a pawn up, KomodoDragon with a passer in the center. The white king came forward and Ethereal couldn't stop the passer, the game ended in a tablebase win.

game 24, Koivisto - SlowChess: Evals were stable until move 32, then started increasing as a series of exchanges reduced to a QRB vs QRB position with white a pawn up. Koivisto exchanged queens and captured another pawn, creating a passer on the queen side. The engines shuffled for a while after a pawn exchange that removed the last black pawn, then Koivisto found a way to reduce to a tablebase win. 

game 26, Stoofvlees - Koivisto: Koivisto moved its king without castling but castled short by walking, while Stoofvlees castled long. Stoofvlees captured a rook for a knight and the engines reduced to a RR vs RB position. Koivisto was 3 pawns up, Stoofvlees used its active rooks to capture all the black pawns with one last white pawn left. The 7-man position was a win for white, it took another 25 moves to reach a (6-man) tablebase win.

Standings after RR1: Stockfish Leela KomodoDragon +2, Berserk Stoofvlees 0, SlowChess Ethereal Koivisto -2. Still very early and the reverse games have to be played, yet the top 3 engines are already in their expected place. Ethereal and Koivisto are under-performing so far.

game 32, Stoofvlees - SlowChess: There were only a few excanges after the start, Stoofvlees castled long despite the open c file. Evals started to increase and there was a period of shuffling, then Stoofvlees opened the king side. After a series of exchanges the game reached a double rook ending with white a pawn up. Both engines had advanced passers, while they dealt with those Stoofvlees captured another pawn and reduced to a tablebase win. There were two white wins in this game pair.

game 35, Koivisto - Leela: The engines castled in opposite directions, there were many exchanges after the start and the game reached a RRN vs RRN position. Leela's eval remained low, it had a pawn majority on the king side and Koivisto had one on the queen side. After trading pawns each engine had two connected passers, then Leela gave its knight for the remaining white pawns. There was one black pawn left, for a while the engines shuffled in the 8-man position. Suddenly Koivisto's eval jumped, Leela's eval reacted only 4 moves later. Koivisto used back rank mate threats to reduce to a tablebase win. Did Leela blunder here? There were two white wins in this game pair. 

game 37, Stockfish - Berserk: Stockfish was up a pawn but evals were low in the first 25 moves. Stockfish's eval started to increase after it gave a pawn back and created a passer. Berserk thought it was safe for more than 10 moves, its eval only reacted after a long think and the game reached a rook ending. Stockfish was a pawn up and it had connected passers in the center. Berserk couldn't avoid a queening, game over. 

game 38, KomodoDragon - Koivisto: Both engines castled short, the first exchange in the game opened the g file and both kings hid in the corner. After a few piece exchanges and some shuffling evals started to increase as KomodoDragon walked its king to the queen side. KomodoDragon pushed the h pawn forward and prepared for an attack on the black king, Koivisto countered with a knight sacrifice to open the center. Koivisto tried to threaten the white king and it pushed a passer to the 7th rank, KomodoDragon reduced to a NN vs N position and captured the black passer. KomodoDragon had enough pawns left to win.

game 39, Leela - SlowChess: Evals jumped after the start, the engines exchanged queens and SlowChess moved its king forward to connect the rooks. Leela gave a pawn to open the d file, then doubled rooks in the file and attacked. Leela captured a rook for a bishop, SlowChess was up two pawns but Leela moved a rook forward and created a passer on the king side. SlowChess gave a knight to capture the passer, Leela converted the RRN vs RB position easily. 

game 40, Ethereal - Stoofvlees: Ethereal's eval increased gradually from the start, the black queen was out on the king side and Ethereal attacked through the queen side. After opening the a file the white queen moved to the 7th rank, Ethereal moved a rook forward as well. Stoofvlees' eval started to increase as it saw the danger much too late, Ethereal moved a second rook forward and captured a bishop. Stoofvlees pushed a passer to the 2nd rank but Ethereal was back on time to block. Ethereal gave a rook for a bishop to capture the passer, then used a mate threat to reduce to a NN vs R position two pawns up. The game ended in a tablebase win. There were two white wins in this game pair. 

game 45, Stockfish - Koivisto: Evals increased slowly from the start though there were only a few exchanges. Stockfish increased the pressure on the black king, its own king looked exposed but was quite safe. Stockfish placed a knight on d6, then replaced it with a rook and exchanged it for two minor pieces. The game reached a BN vs R position with white a pawn up, Stockfish used an unstoppable passer to win. 

game 47, KomodoDragon - Stoofvlees: Evals slowly increased from the start, Stoofvlees sacrificed a knight for a pawn and started a series of pins and exchanges in the center. As a result the game reached a QRB vs QRB position with the black king exposed. Stoofvlees gave a rook for a bishop to protect its king, KomodoDragon used checks to capture pawns and then captured the queen for a rook. KomodoDragon had a winning material advantage, it chose to give it away and still won only two pawns up. There were two white wins in this game pair. 

game 48, Leela - Ethereal: Evals started to increase after move 22 as Leela prepared an attack on the king side. It pushed pawns forward leaving its king without pawn support, then gave a knight for a pawn. The black king was exposed with white pawns advancing and the white queen in front. Ethereal couldn't get rid of the white pawns, after a while there was a line of 4 pawns advancing on the king side backed by the white major pieces. After exchanging queens nothing could stop the pawns, Leela gained material and queened one pawn to win.

game 49, Leela - Stockfish: see featured game below.

game 53, Stockfish - SlowChess: There were a few exchanges after the start, from move 25 SlowChess stabilized its pawns and played waiting moves. Stockfish moved a few pawns and exchanged a few pieces, other than that the engines shuffled and evals were stable. On move 104 Stockfish exchanged a pair of knights and its eval increased a little. On move 121 it went a pawn up, evals jumped as the engines reduced to a queen ending. SlowChess managed to capture two pawns, but the black king was trapped on the back rank and the white king was active, Stockfish reduced to a tablebase win.

game 54, Koivisto - Stoofvlees: Stoofvlees moved its king without castling and Koivisto castled long. Koivisto gave two pawns to open the position, Stoofvlees tried to threaten the white king but was not strong enough. Koivisto gave a rook for a knight to open the center and the black king was in a mating net. Koivisto sacrificed a knight and its queen before mating. There were two white wins in this game pair.

game 55, Berserk - Ethereal: The engines castled in opposite directions, most minor pieces were exchanged after the start. Berserk placed a pawn on h6, Ethereal was weak on the dark squares. Evals slowly increased though the engines seemed to be mostly shuffling, the black king was vulnerable on the long diagonal. On move 45 there was a series of exchanges that left a double rook ending with white a pawn up and a queen side passer. After exchanging a pair of rooks Berserk created a passer on the king side and Ethereal couldn't stop both, Berserk queened and won.

Featured game: Leela - Stockfish
game 49

The engines castled in opposite directions. Starting from move 9 the engines followed a long PV agreement where the engines exchanged queens and a few minor pieces, and Leela went a pawn up. Stockfish's eval was mostly stable but Leela's eval slowly increased. Stockfish doubled its rooks on the queen side facing the black king, Leela was not concerned and even Stockfish's eval started to increase. On move 29 the game reached a RRN vs RRN position.  

Leela's advantage seemed minimal but the evals made it clear what the result would be. Leela controlled the open d file, making sure the black king could not walk to the queen side where Leela had a pawn majority. Stockfish created a passer on the king side but didn't have support to push it forward. The white king moved forward, Leela exchanged pawns and created connected passers on the queen side. 

Stockfish could not stop the white passers, for each one it lost a rook and the game ended quickly. Leela won the game pair. 

Season 24 league 1 statistics

A summary statistics table of previous stages and seasons.  

Draw rate, wins

Final draw rate was 52.7%. 

Game termination

The three most common game termination causes were:
39.0% - TCEC draw rule
32.2% - SyzygyTB
19.3% - Mate

There were no crashes in the league.

Moves per game

Median= 70.3
Average= 76.9

There were 41 games longer than 100 moves, the longest was 249 moves (Fritz - Marvin, game 159, white win). 

Time per game (hours)

Median= 1:04
Average= 1:02

Openings

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

The engines almost no freedom to choose the opening variant, in all the game pairs the ECO code and the opening variant was repeated.

Reverse pairs, wins

Reverse pairs, same moves

Pairs of reverse games diverged less quickly than usual, only 17.4% diverged immediately out of book, 59.8% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 20 plys (RubiChess - rofChade, games 28 and 94, Robatsch defence, Rossolimo variation, two white wins)

Season 24 league 1

Final standings

Koivisto and Berserk advance to the premier division. Koivisto led from the start, its lead increased and none of the other engines came close. It beat all engines in at least one game pair, except for drawing against Berserk and losing one game pair to Seer. The race for 2nd place was very close with 5 engines within a point of each other until the last rounds. Berserk qualified in the end, it is the only engine without any game pair loss in the league, and it had two game pair wins against the other engines in the race.

Minic, Fritz, BlackMarlin and Marvin are relegated to league 2. These engines were at the bottom of the table from the start and their relegation was predictable. They lost 48/64 of the game pairs played against the higher ranked engines, BlackMarlin was the only one that managed one game pair win against ScorpioNN. Except for Minic the relegated engines advanced from league 2, Igel is the only qualifier that survived league 1.

The two qualifiers will play in the premier division together with:
Stockfish Leela KomodoDragon Ethereal Stoofvlees SlowChess - all played in season 23 premier division.

Interesting games

game 8, Revenge - RubiChess: Revenge castled long while RubiChess did not find the right time to castle. Revenge gave a pawn and opened the center, then it attacked the black king and forced it to move to the king side. The result of the attack was a QRB vs QRB position with white two pawns up. Revenge captured the remaining black pawns, RubiChess couldn't avoid a queening and game over.

game 13, Koivisto - Igel: The engines the d file and Koivisto placed a rook safely on d6, then gave a bishop for a pawn and exposed the black king. A knight sacrifice opened the 6th rank and Koivisto chased the black king with its queen and rook all the way across the board. The chase stopped when Koivisto captured a queen for a rook, resulting in a Q vs RNN imbalance with white 3 pawns up. There were 3 connected white passers on the king side, Igel tried to block but after exchanging a pair of rooks Koivisto's passers were unstoppable. The game ended in mate with 3 queens on the board.

game 15, ScorpioNN - rofChade: ScorpioNN had a bishop pair advantage, pawn exchanges opened the board and the game reached a RBB vs RNN position with white a pawn up. Koivisto created a passer on the king side, then captured another pawn and created a passer on the queen side. rofChade blocked the passers until ScorpioNN exchanged bishop for knight and the white king moved forward to help. ScorpioNN pushed both passers slowly, eventually queening both and mating.

game 18, BlackMarlin - Revenge: The engines shuffled in an opposite color bishops ending with white a pawn up. This should have been a draw but Revenge blundered and BlackMarlin managed to avoid a 50-move draw and capture two pawns, enough for a win.

game 19, Igel - Revenge: Igel had a space advantage and a significant eval advantage from the start. Exchanges opened the position, Igel went two pawns up with two passers on the queen side. One passer reached the 7th rank, Revenge lost a rook to capture it and Igel converted the RRN vs RB position easily. 

game 24, Koivisto - Berserk: The game reached a RBB vs RNN position and evals slowly increased. Koivisto went a pawn up and created two passers, one on each side. Berserk had a passer in the center but it was busy trying to stop the white passers advance. Berserk lost a knight for one passer, the game ended in a tablebase win with one last white pawn.

game 28, RubiChess - rofChade: Evals slowly increased after move 20, both engines created a passer but the white passer was more advanced and better protected. The game reached a RRN vs RRB position, RubiChess captured the black passer and pushed its own to the 6th rank, then captured two more pawns. After all rooks were exchanged the game ended in a tablebase win.

game 36, Berserk - ScorpioNN: Berserk was up a rook for a knight for a short while but gave the material back, resulting in a QRB vs QRB position. The black king was more exposed and the black pawns isolated, Berserk captured a pawn and then captured a rook for a bishop. Berserk's evals showed mate scores, it exchanged queens and reduced to a tablebase win.

game 37, ScorpioNN - Igel: ScorpioNN was 2 pawns up in a BN vs BB position with high evals, but it couldn't find a way to convert. 

game 49, Fritz - Igel: The white king was uncastled in the center, but more significantly Fritz had a pawn on h6 and there was a black bishop trapped in the corner. Igel had the strength to capture the h6 pawn but it left it there, probably not wanting an attack on the h file. Fritz captured a pawn on the queen side, Igel moved its bishop out of the corner and later traded it for a white bishop. Fritz created a passer on the queen side, after exchanging queens Igel lost a rook to capture the passer. The game ended in a tablebase win.

game 55, Igel - rofChade: Evals were high and increasing from the start, the g file was half opened and the black king was under threat. rofChade exchanged pieces to protect its king, Igel captured pawns, the game reached a RB vs RN position with white a pawn up. For a while rofChade tried to force stalemate, Igel avoided that and reduced to a tablebase win.

game 58, Berserk - Revenge: Evals started to increase around move 30, Revenge controlled the open a file and Berserk pushed the h pawn forward. Berserk opened the h file and increased the pressure on the king side, then it gave a bishop for a pawn and exposed the black king. In the attack Berserk sacrificed a rook but captured the queen, leading to a QN vs RBB position. Revenge tried to protect its exposed king with its pieces, Berserk used a passer to capture a bishop, then reduced to a won knight vs pawns ending. 

game 63, Revenge - ScorpioNN: For over 30 moves evals were below 1, ScorpioNN was a pawn up and no worried. Evals started to jump when in a series of exchanges Revenge gave a piece and reduced to a RN vs RBN position. Revenge created connected passers as well as captured two advanced black pawns. One passer was on the 7th rank and ScorpioNN had to give the rook to stop it. The game ended in a tablebase win. 

game 64, Seer - Berserk: Seer focused its pieces on the king side with a pawn on h6, while Berserk went a pawn up and its queen moved forward on the queen side. Seer was strong on the dark squares and it threatened mate on the long diagonal, a series of exchanges reduced to a Q vs RB ending. Seer captured pawns and the h6 pawn became a passer, Berserk tried to trap the queen but Seer used zugzwang to force a queening and win.

Standings after RR1: Koivisto +4, Igel RubiChess +2, Berserk ScorpioNN +1, Revenge Seer rofChade 0, Minic -1, Fritz -2, Marvin -3, BlackMarlin -4. Koivisto has a small lead, there a 7 engines within one point of second place. The 4 engines with negative scores include 3 of the qualifiers from league 2.

game 85, Revenge - Igel: A long series of exchanges reduced to a same color bishop ending with white a pawn up. All pawns except one were blocked, Igel tried to make sure the white king couldn't move behind the pawns. After a long shuffle Revenge found a way to force the black bishop away and the white king advanced. The black king moved to protect the pawns in the center, Revenge gave two pawns and queened on the king side, game over. 

game 90, Berserk - Koivisto: The engines gradually exchanged pieces while evals increased, the game reached a double rook ending with white a pawn up. Koivisto regained the pawn but Berserk created connected passers. Koivisto blocked the passers and avoided exchanging rooks, Berserk captured two pawns and pushed a passer to the 7th rank. Koivisto pushed its last pawn forward, it captured a white passer and exchanged a pair of rooks. Both engines queened a pawn, Koivisto was first but Berserk promoted with check, this was enough to force mate.

game 91, Igel - Berserk: Igel had an eval advantage despite sacrificing a knight, it threatened the black king through the open king side. Berserk found a way to walk its king safely to the center and evals came down. After a period of shuffling evals turned negative as the engines opened the position. Berserk captured pawns and created passers, the game reached a queen ending with white 3 pawns up which Berserk converted easily. 

game 92, Koivisto - ScorpioNN: The game reached a QRR vs QRR position with white a pawn up. The black king was exposed, Koivisto gave checks and captured two more pawns, then reduced to a winning queen ending. 

game 94, rofChade - RubiChess: There were a few pawn and minor piece exchanges in the first 50 moves and evals were mostly stable. After a period of shuffling there was a series of exchanges that left a QN vs QB position with white a pawn up. The engines cleared the queen side pawns and shuffled some more. rofChade's eval started to increase, it found a way to exchange queens and move its king forward. The black bishop and the white pawns were on opposite color squares, rofChade managed to capture a pawn and push a passer to the 7th rank, enough to win. Did RubiChess blunder here?

game 102, ScorpioNN - Berserk: The game reached a BB vs BN with white a pawn up, ScorpioNN had advanced connected passers and Berserk also had a passer. There was a long period of mostly shuffling, on move 100 Berserk exchanged its knight for one of the white bishops and reduced to an opposite color bishop ending. However, ScorpioNN created another passer and Berserk couldn't control them all, it lost the bishop for a passer, game over. Could Berserk have held here?

game 105, Koivisto - RubiChess: There were many early exchanges and the game reached a RRB vs RRB position with white a pawn up. Pawn exchanges opened files and Koivisto captured another pawn. RubiChess regained a pawn and exchanges bishops, evals started to increase after move 70. At first the engines seemed to shuffle but Koivisto found a way to exchange a pair of rooks and capture a pawn. Koivisto used passers to win.

game 110, Seer - rofChade: After the engines exchanged queens rofChade moved a rook forward on the queen side and Seer blocked its way back. rofChade didn't try to free its rook, Seer moved its king to take it and rofChade traded the rook for a bishop. Seer reduced to a R vs B ending, it captured pawns and queened a passer to win.

game 114, Fritz - ScorpioNN: ScorpioNN was up a pawn with the black queen moving forward on the queen side, for a long time it seemed Fritz tried to hunt the black queen and ScorpioNN refused to move it back again. After move 45 evals started to increase, the black queen moved to the king side and threatened the white king. Fritz counter-attacked from the queen side, it regained the pawn and created a passer. ScorpioNN could not prevent a queening and Fritz mated.

game 118, Koivisto - Revenge: Revenge gave a pawn, Koivisto thought this was a mistake and it led to a B vs R trade. For a while there were no exchanges though evals slowly increased. A series of exchanges reduced to a R vs BN position, Koivisto captured a pawn and created connected passers on the queen side. Koivisto gave a rook for a bishop to make the passers unstoppable, mate was quick after the queening.

game 124, Revenge - Berserk: Thee were many early exchanges that left only QBN vs QBN, evals started to increase while the remaining minor pieces were exchanged. Revenge was a pawn up in a queen ending, it had a passer and its king was less vulnerable. Progress was slow but sure, Revenge captured another pawn and pushed its passer forward to force the win.

game 127, Igel - RubiChess: The engines exchanged pieces and material was equal but evals slowly increased. The black pawn structure was weak, when only RN vs RB remained Igel captured two pawns. Both engines had advanced passers, but after both were gone RubiChess had no more resources. Igel pushed its two remaining pawns to win. 

game 130, Berserk - Seer: The game reached a RRN vs RRN position, material was equal but Berserk had a space advantage and evals were increasing. Berserk created connected passers in the center with pawn exchanges, and exchanged a pair of rooks. Seer had passers on the king side but it could not stop the white pawns charging in the center and lost its knight. Berserk queened another passer and mated.

Standings after RR2: Koivisto +8, Revenge +4, Igel Berserk +3, ScorpioNN RubiChess +2, rofChade +1, Seer 0, Minic Fritz -4, BlackMarlin -7, Marvin -8. Koivisto is leading with 8 game pair wins and no loss. The fight for 2nd place is wide open with 5 engines within a point of each other. Revenge came back to current 2nd with 5 wins in RR2 (and one loss to Koivisto), drawing 3 game pairs that it lost  in RR1 (including against BlackMarlin). The bottom 4 engines are clear at this point, 3 qualifiers and Minic. They lost 23/32 game pairs against the other 8 engines with no win.

game 134, Koivisto - rofChade: rofChade moved its king side rook early, the black king moved forward without castling. Koivisto went up a pawn and had an advanced passer on the queen side, rofChade hid its king behind the passer. The engines exchanged pieces and pawns, rofChade captured the passer and Koivisto captured a second pawn. In a RRB vs RRN position Koivisto captured a third pawn, it queened a passer and mated.

game 136, ScorpioNN - Seer: Queens were off early, the engines exchanged pieces and pawns gradually and there were long periods of shuffling with mostly stable evals. On move 75 ScorpioNN went a pawn up in a RRB vs RRB position and evals started to increase. ScorpioNN captured a second pawn and exchanged a pair of rooks. After ScorpioNN captured a third pawn Seer could not stop the white passers, game over.

game 142, Minic - ScorpioNN: ScorpioNN was up a pawn early, but Minic had an eval advantage. After a series of exchanges the game reached a RR vs RB position. ScorpioNN pushed pawns forward on the queen side, Minic exchanged a pair of rooks and pushed a passer on the king side. The game ended in a tablebase win just before Minic captured the bishop the passer.

game 143, rofChade - Berserk: rofChade went a pawn up and the game reached a RB vs RN position. rofChade had a pawn majority on the queen side, the white king moved to assist the pawns while the white rook moved forward. After some preparations rofChade created a passer and captured another pawn, then exchanged rooks. The white king came forward and rofChade trapped the knight, Berserk couldn't avoid a queening and mate.

game 145, Koivisto - Igel: Koivisto gave 3 pawns and a rook, Igel's king was exposed in the center and the black queen far on the 1st rank. Koivisto attacked the black king, Igel surrounded its king with pieces. Igel gave back the material but in a QRN vs QRN position its king was still in danger. Koivisto captured a knight and exchanged queens, it took more than 30 moves to capture 2 pawns and force mate.

game 149, RubiChess - Seer: The engines castled in opposite directions, RubiChess gave a pawn and half opened the h file facing the black king. Seer tried to counter on the queen side but was not effective. RubiChess attacked the black king, it won a bishop and Seer hid its king behind a white pawn. In a QRB vs QR position RubiChess captured all the black pawns, mate followed.

game 151, Igel - Revenge: The engines gradually exchanged pieces and the game reached a RRN vs RRN position. Both engines had a passer on the queen side. Revenge captured the white passer, Igel captured two pawns and created a passer in the center. Igel captured the black passer, Revenge tried to avoid exchanging pieces but eventually it lost a knight for a passer and the engines exchanged a pair of rooks. Igel reduced to a tablebase win.

game 162, Revenge - Seer: There were only a few pawn exchanges until move 49, though evals slowly increased. Then in a series of exchanges the queen side opened and all rooks were off. Revenge created connected passers and reduced to a BNN vs BBN position. Eventually Seer lost a piece for a passer, the game reached a B vs pawns ending that Revenge converted easily. 

game 173, Revenge - rofChade: Both engines did not castle, evals slowly increased as the engines exchanged pieces and pawns. The game reached a RBN vs RBN position, with 3 white pawns on the queen side and 3 black pawns on the king side. The white passers were more dangerous and supported by the king, rofChade chose to give a bishop to capture two pawns. Revenge protected its last pawn while capturing all the remaining black pawns, then converted the 8-man position to a tablebase win.

game 179, Berserk - RubiChess: The engines castled in opposite directions, the black king was more exposed after Berserk opened the f file and exchanged a pair of rooks. Berserk was patient and there was a period of shuffling with evals increasing slowly. RubiChess exchanged a pair of pawns and opened the center, Berserk exposed the black king and threatened mate on the long diagonal. RubiChess traded bishops and removed the threat, in a QRN vs QRN position Berserk used the exposed black king to exchange queens and capture 3 pawns. RubiChess couldn't stop the passers, game over.

game 182, RubiChess - ScorpioNN: ScorpioNN kept its king in the center, RubiChess opened the d file and exchanged queens. RubiChess sacrificed a bishop to expose the black king, then regained the material and placed a rook on the 7th rank. In a double rook ending RubiChess managed to move its second rook to the 7th rank, the black king was trapped and waited to be mated by a promoted passer. 

game 190, Berserk - Revenge: Berserk went up a pawn early, it had a pawn majority on the queen side. The engines exchanges pieces and pawns with evals slowly increasing. Eventually Berserk created a doubled passer, Revenge stopped one passer on the 7th rank but lost a bishop. The white king came forward, Berserk gave a rook for a knight and reduced to a tablebase win in a BN vs R ending. 

game 195, Revenge - ScorpioNN: The game reached an opposite color bishops ending with white two pawns up. After a long shuffle Revenge gave a pawn and created a passer, then ScorpioNN blundered and Revenge's eval indicated a win. ScorpioNN saw the mistake only 7 moves later. With only 2 white pawns and one black left, the white bishop protected a passer on the 7th rank and controlled the black pawn. Revenge had time to walk with its king to assist the other white pawn, forcing ScorpioNN to lose its bishop and the game.

Standings after RR3: Koivisto +12, Igel Berserk Revenge +5, RubiChess +4, rofChade +3, ScorpioNN +1, Seer 0, Minic -7, Fritz -8, Marvin BlackMarlin -10. Koivisto is on its way to win the league. There are 3 engines tied in 2nd place and two more within a point. 

game 206, RubiChess - Revenge: Revenge captured a pawn early but was slow in developing the queen side pieces, RubiChess opened the h file and threatened the black king. RubiChess gave another pawn and added a threat on the long diagonal, Revenge blocked with a pawn but lost a bishop. RubiChess pushed pawns and opened the f file, it also created an advanced passer in the center. Revenge tried a desperate attack on the white king, this only delayed mate.

game 209, Berserk - rofChade: The center and king side were mostly blocked and the attention of both engines was on the queen side. The engines opened the queen side and cleared away all pawns, Berserk placed a protected knight on c5 and threatened to move a rook forward. rofChade gave a rook to capture the white knight, the game reached a QR vs QN position. Berserk used threats on the black king to force a queen exchange, the white king moved forward. Berserk created an unstoppable passer to win.

game 213, rofChade - ScorpioNN: The engines gradually exchanged pieces and pawns, rofChade went a pawn up with a passer on the queen side. The game reached a RN vs RB position, the engines mostly shuffled for 30 moves and evals started to increase. rofChade managed to get its king forward and to block the black king away from the passer. rofChade gave a rook for a bishop and ScorpioNN could only stop the passer by giving its rook. The knight vs pawns ending was a win for white.

game 226, rofChade - RubiChess: rofChade was up a pawn early, the engines exchanged pieces until only QB vs QB remained. Evals slowly increased, RubiChess was weak on the dark squares and its queen had to protect the king since the black bishop was light squared. rofChade opened the king side and moved its king forward. After exchanging queens rofChade gave a pawn and created a passer, RubiChess lost its bishop to stop the passer. The bishop vs pawns ending was a win for white.

Standings with 6 rounds to go: Koivisto +13, Igel Berserk +6, RubiChess Revenge +5, rofChade +4, ScorpioNN +2, Seer 0, Minic -7, Fritz -10, BlackMarlin -11, Marvin -13. Every game counts in the race for 2nd place, especially head to head decisive results. Berserk beat rofChade and is in 2nd place tied with Igel. RubiChess beat Revenge but lost to rofChade, Revenge also failed to beat BlackMarlin. rofChade also beat ScorpioNN, it is still hanging on the leaders, but time is running out.

game 229, Seer - Igel: Seer was a pawn up early, the white king moved forward without castling. Seer created a passer on the queen side, Igel regained the pawn but evals slowly increased. Seer gave a rook for a knight and pawn to add a connected passer and Igel tried to block. Seer pushed one passer to the 7th rank, after a while the game reached a QN vs QR position. The white king came forward, Igel traded all pieces to stop the passer. The material was equal but Seer had an unstoppable passer to win.

game 231, BlackMarlin - rofChade: BlackMarlin gave a pawn and opened the king side, its king stayed in the center and later it castled long. The engines exchanged pieces and BlackMarlin captured pawns, the game reached a RBN vs RBB position with white two pawns up. BlackMarlin had a passer still on the 2nd rank, the engines exchanged knight for bishop, it took 35 moves before the passer moved. The white king moved forward to support, BlackMarlin captured a pawn and created more passers. rofChade couldn't prevent a queening and mate.

game 235, Igel - ScorpioNN: Igel attacked the king side early, resulting in a R vs NN imbalance and the black king walking to the queen side. Pawn exchanges opened the board, Igel targeted the exposed black king and captured pawns. It was 4 pawns up when ScorpioNN captured a rook for a bishop and reduced to a QR vs QRN position. ScorpioNN captured a few pawns back but Igel reduced to a winning queen ending. 

game 237, Koivisto - RubiChess: Evals increased slowly as the engines exchanged pieces and pawns. The game reached a RN vs RN position with white a pawn up. Koivisto had a queen side passer, once the white king came to assist RubiChess could not stop the passer advancing. Koivisto queened the passer and mated.

game 239, rofChade - Revenge: The engines castled in opposite directions, both pushed pawns facing the opponent's king. Revenge opened the a file, then gave a knight for two pawns on the king side. Revenge tried to attack the white king, it gave a rook for a knight but rofChade gave the exchange back to keep its king safe. rofChade pushed a passer to the 7th rank and reduced to a RN vs R position. The game ended in a tablebase win.

game 245, RubiChess - Berserk: The engines castled in opposite directions, there were no pawn attacks and the engines gradually exchanged pieces. Evals slowly increased though Berserk went a pawn up, the game reached a RB vs RN position. RubiChess regained the pawn and created connected passers on the queen side. The black king moved to block the passers, Berserk tried to counter with a passer in the center but was not strong enough. RubiChess had a rook on the 7th rank, the black rook had to defend the back rank, eventually RubiChess captured the knight and won. 

Standings with 3 rounds to go: Koivisto +14, Berserk Igel Revenge RubiChess +6, rofChade +4, ScorpioNN Seer +1, Minic -8, Fritz BlackMarlin -11, Marvin -14. Four engines tied for 2nd place! Igel and rofChade lost games as black against weaker engines, top engines beat weaker engines as white. rofChade probably does not have a chance of  being 2nd at this stage, for the others every game counts.

game 248, ScorpioNN - RubiChess: ScorpioNN castled long and opened the king side, RubiChess kept its king in the center. RubiChess gave a rook for two knights, ScorpioNN attacked through the open e file and the black king had to run to the king side. The engines reduced to a RB vs BN position, ScorpioNN had passers on both sides. RubiChess lost the bishop to stop one passer, the other queened and ScorpioNN mated.

Standings at the top with 2 rounds to go: Koivisto +14, Berserk Igel +7, Revenge +6, RubiChess +5, rofChade +4. Igel and Berserk beat weaker engines as white, rofChade only managed a draw, Revenge held a draw as black against Koivisto. rofChade and RubiChess are probably out of the race.

game 253, rofChade - Igel: There were only a few exchanges after the start, most of the board was blocked by long pawn lines. A pawn exchange opened the h file, then rofChade used a knight exchange to create a passer in the center. rofChade gave the passer and created another on the king side, the game reached a QBN vs QBN position with white a pawn up. Igel tried to attack with its queen, rofChade captured more black pawns and was 4 pawns up. After exchanging queens nothing could stop the passers, game over. 

game 255, Seer - Koivisto: Seer was up a pawn from the start, the engines exchanged pieces until only QRR vs QRR were left. Evals started to increase, the engines exchanged all rooks and Seer created a passer. Koivisto captured white pawns while Seer pushed he passer to the 7th rank. The game reached a 7-man position won for white, Seer had access to 7-man tablebases but it still took almost 50 moves to get to a 6-man adjudication. 

Standings at the top before the last round: Koivisto +13, Berserk +7, Igel Revenge RubiChess +6, rofChade +5. Berserk held a draw as black against Revenge, after Igel's loss Berserk is alone in 2nd place. RubiChess beat a weaker engine as white, still has a small chance. 

Igel and RubiChess drew their last game. Revenge held a draw as black against ScorpioNN. Berserk only needed a draw but it won as white against Seer, making sure it qualifies to the premier division.