Season 25 premier division, after RR8

Scheduling note: I will be on vacation and will miss the final DRRs of the premier division. Based on the current results it is safe to say that Stockfish and Leela will be in the superfinal, even before the playoff is played. I haven't decided whether to try to complete the premier division entries when I come back (with a backlog of >100 games) or whether to cover the ongoing games and go back to ones I missed later... We'll see.

Standings after RR8

Stockfish drew as white against KomodoDragon, the first game it didn't win with bias. This was also only the 3rd game pair Stockfish didn't win after 28 played. Leela won 5 game pairs against the bottom 5, it drew against KomodoDragon and lost against Stockfish for the 3rd time. Ethereal and RubiChess both had 2 game pair wins and 2 losses, Ethereal keeps its slim lead in 4th place.

Interesting games

game 171, Stockfish - RubiChess: Stockfish opened the king side and RubiChess castled long. RubiChess gave a bishop for a pawn and exposed the white king, this led to a series of exchanges where the engines traded RN for Q. The engines reduced to a Q vs RN ending, evals were high but its still took a long time to convert. Stockfish had a passer and the white queen could give checks, pin pieces or threat forks. After 20 moves Stockfish created a second passer, RubiChess couldn't prevent a queening and then mate.

game 174, RubiChess - Stoofvlees: The center was blocked and there were only a few pawn exchanges after the start. Evals were stable, Stoofvlees offered a rook for a bishop but that would close a file and RubiChess refused. After move 35 evals started to increase, RubiChess opened the king side and created an advanced passer. Stoofvlees gave a knight for the passer, RubiChess captured a pawn and created connected passers in the center. Stoofvlees gave up when the white passers advanced, it gave material and was mated.

game 177, Ethereal - Igel: Ethereal castled long and gave a pawn on the king side. Ethereal slowly moved its major pieces to the king side, after the g file opened Ethereal gave another pawn and tripled its major pieces on the h file. Ethereal gave a rook for a knight and pawn and exposed the black king, Igel surrounded its king with pieces. Ethereal placed two static knights on the queen side while its queen and rook kept moving and making threats from all sides. Igel protected its king but it lost a few pawns, Ethereal created connected passers on the queen side. The passers slowly advanced supported by the white king, the game reached a N vs R ending. Igel lost the rook for a passer, Ethereal queened another and mated.

game 178, Stockfish - SlowChess: Stockfish captured a pawn early, the center was blocked and the engines formed long pawn lines without exchanges. Evals increased while the engines shuffled and the white king walked to the queen side. On move 48 Stockfish started to open the king side, it gave back the pawn and exposed the black king. After exchanging queens Stockfish captured a pawn and reduced to a RBN vs RBN position. Stockfish captured a second pawn and pushed connected passers forward, it gave a rook to promote to a queen and mate followed.

game 180, Leela - RubiChess: Leela moved its king to the king side without castling. All pieces were on the king side, Leela's eval jumped after RubiChess opened the f file. RubiChess gave a rook to get rid of a forward knight, Leela continued to exchange pieces until reaching a R vs N ending. Both engines pushed passers, RubiChess lost its knight, both engines queened but Leela was first and forced mate.

game 182, KomodoDragon - Leela: KomodoDragon castled long while Leela kept its king in the center. KomodoDragon captured an early pawn, the engines exchanged many pieces and pawns and Leela regained the pawn. The game reached a RN vs RB position, KomodoDragon kept the black king away and captured a pawn, reducing to a rook ending. The game continued for more than 25 moves, first KomodoDragon captured another pawn, then with 3 passers the engines reduced to a tablebase win.

game 185, Stockfish - Igel: Stockfish created a central passer with pawn exchanges, Igel captured a pawn but couldn't get rid of the white passer. Stockfish protected its passer with many pieces, after some preparations there was a series of exchanges that reduced to a RB vs RB position. Stockfish went two pawns up and pushed more passers forward. Igel lost its rook and the game ended in a tablebase win.

game 187, Leela - SlowChess: Evals were low until move 22, Leela thought SlowChess blundered on move 25. In a series of exchanges the engines reduced to a RB vs RN position, SlowChess was a pawn up but its pawns were vulnerable. Leela pushed a passer forward and SlowChess lost its knight for it. Leela captured pawns and pushed more passers forward, the game ended in a tablebase win.

game 188, RubiChess - KomodoDragon: Queens were off early, RubiChess went a pawn up and in an unusual sequence of exchanges the engines reduced to a RBN vs RNN position. After trading a bishop for a knight RubiChess created a passer. KomodoDragon lost more pawns trying to stop the passer, it gave up its pieces and the game ended in a tablebase win.

game 192, Stockfish - Stoofvlees: Stockfish gave a rook for a knight early and opened the king side. Evals were mostly stable, Stoofvlees exchanged pieces and protected its king. The game reached a QRB vs QRB position when Stockfish's eval jumped. Stockfish attacked the black king and captured a pawn, then reduced to a queen ending. Stockfish saw the win though it took more than 20 moves to reach a tablebase win.

game 196, KomodoDragon - SlowChess: There were no exchanges after the start but evals started to increase. On move 22 SlowChess opened the center and gave a knight for two pawns. The engines continued to exchange pieces and the game reached a QB vs Q position. KomodoDragon used checks to capture pawns, then exchanged queens. KomodoDragon didn't try to finish the game quickly, it took almost 40 more moves to get a tablebase win.

Standings after RR7: Stockfish +23, Leela +10, KomodoDragon +6, Ethereal 0, RubiChess -2, Stoofvlees -7, Igel -11, SlowChess -19. Stockfish and Leela continued to win as usual, except for Leela's loss to KomodoDragon. KomodoDragon also lost to RubiChess. Ethereal held a draw as black against RubiChess, it is still in 4th place.

game 200, Leela - Stoofvlees: Leela castled long and forced the black king to move without castling. Stoofvlees gave two pawns and opened the queen side, Leela gave a rook for a knight and exchanged pieces to keep its king safe. Leela was two pawns up, it pushed a passer to the 7th rank. Stoofvlees gave a bishop and captured the passer, Leela attacked the black king. Stoofvlees lost material and was mated.

game 201, Leela - Igel: All pieces were on the board until move 27 when Igel gave a rook for a knight. Igel pushed pawns on the king side and tried to attack the white king, Leela exchanged pieces and reduced to a RB vs RB position. Leela was a pawn up, both engines had passers but the white ones were faster. Leela queened a passer and mated.

game 202, Stoofvlees - RubiChess: There were no exchanges after the start, the engines blocked the center and queen side. On move 45 Stoofvlees opened the king side and RubiChess captured a pawn. RubiChess gave a rook for a knight and walked its king to the queen side. The engines exchanged minor pieces and opened files on the king side, then there was a long period of shuffling. On move 97 Stoofvlees moved its queen forward followed by a rook. After a while the engines exchanged queens and reduced to a RRB vs RBN position. Stoofvlees trapped and captured the black bishop, RubiChess gave two pawns in desperation and created a passer. Stoofvlees queened and mated. There were two white wins in this game pair. 

game 204, Ethereal - SlowChess: There were no exchanges after the start, the center and queen side were blocked. Ethereal castled long and slowly prepared an attack on the king side. Evals slowly increased, there was one minor piece exchange and Ethereal pushed pawns on the king side. On move 58 Ethereal gave a knight for two pawns and exposed the black king. SlowChess tried to counter on the queen side but Ethereal hid its king behind a black pawn. SlowChess gave back a knight and surrounded its king with pieces, but it lost material and was mated.

game 205, Igel - Ethereal: Igel castled long, then gave a pawn and opened the king side. After exchanging a pair of rooks Igel regained the pawn on the queen side and created a passer. Ethereal had a passer on the king side, the engines shuffled for a while, then reduced to a NN vs BN position. The black bishop was blocked by its own pawns, Ethereal gave it and captured a pawn. Igel used one knight to block the black passer, the other knight captured pawns until there were none left. The game ended in a tablebase win. There were two white wins in this game pair. 

game 209, RubiChess - Igel: There were many early exchanges, the game reached a QRN vs QRN position with white a pawn up. After exchanging rooks RubiChess managed to capture a second pawn and created a passer. RubiChess pushed the passer forward and Igel lost the knight for it. The game ended in a tablebase win.

game 210, Leela - KomodoDragon: Leela castled long and KomodoDragon tried to open the queen side. Leela went a pawn up and exchanged pieces to keep its king safe. The game reached a RB vs RB position, both engines had a passer a square away from promotion. KomodoDragon had to abandon its passer, Leela pushed a second passer forward and forced a queening and mate. There were two white wins in this game pair. 

game 211, Stoofvlees - SlowChess: The engines castled in opposite directions and both pushed pawns facing the opponent's king. Evals started to increase when Stoofvlees gave a knight for two pawns and opened the king side. SlowChess gave a bishop back to let its queen move forward, then queens were exchanged. Stoofvlees doubled rooks on the g file, then captured pawns until it was a pawn up with passers on both sides. The engines reduced to an opposite color bishops ending, Stoofvlees captured two more pawns and that was enough for a tablebase win.

game 212, Stockfish - Ethereal: The engines castled in opposite directions, there were many early exchanges and Stockfish managed to place a pawn on f6. The game reached a double rook ending with white a pawn up, the black king was restricted on the king side. Ethereal managed to capture the f6 pawn and then exchanged a pair of rooks. Both engines had 3 passers, the white ones were connected. That was enough for Stockfish to queen a passer first and force mate.

game 214, Ethereal - Stoofvlees: Stoofvlees gave a pawn early and opened the queen side. The white king was stuck in the center, Stoofvlees gave a knight for a pawn and opened the d file where it doubled queen and a rook. Ethereal was not intimidated, it kept its king safe even when the second black rook moved forward. Ethereal moved its rooks to the 7th rank and attacked the black king. Stoofvlees tried to exchange pieces but it was soon mated.

game 216, KomodoDragon - RubiChess: Evals were stable for a long time, with only a few exchanges. After move 35 KomodoDragon's eval started to increase, it half opened the g file and put all its major pieces there to threaten the black king. RubiChess lost a knight, after a while the engines reduced to a RB vs R position. RubiChess was two pawns up with connected passers, KomodoDragon pushed a passer forward and the black rook had to block it. The white king captured the black passers, KomodoDragon queened and the game ended in a tablebase win. There were two white wins in this game pair. 

game 217, KomodoDragon - Igel: KomodoDragon gave a pawn early, after Igel castled KomodoDragon attacked the king side and exchanged DS bishops. Igel's king side was weak on the dark squares, KomodoDragon regained the pawn and attacked with its major pieces. The game reached a QRB vs QRB position with a white passer on the 7th rank. KomodoDragon captured two pawns and after a while reduced to a same colored bishops ending. A combination of a light squared bishop and pawns on dark squares kept the black king away, KomodoDragon queened a passer and mated.

game 218, RubiChess - SlowChess: The center and queen side were blocked, the engines shuffled and SlowChess walked its king to the queen side. RubiChess' eval started to increase on move 30, in a series of exchanges SlowChess gave a bishop for two pawns and the king side opened. The game reached a RRB vs RR position, RubiChess captured pawns and exchanged a pair of rooks, then it captured the last black pawn and the game ended in a tablebase win.

game 219, Leela - Ethereal: Leela's eval jumped after Ethereal grabbed a pawn on the queen side, Leela opened the h file and threatened the black king. Ethereal placed all its major pieces on the b file as a counter attack, Leela castled its king and kept it safe. Leela gave a second pawn and opened a file in the center, the threat to the black king forced Ethereal to give its queen and the game reached a QRN vs RRB position. Ethereal tried to move its king away, Leela pushed a passer forward. Leela gave a rook and queened, then gave away the material and reduced to a tablebase win.

game 222, Stockfish - Leela: see featured game below.

Featured game: Stockfish - Leela
game 222

After the start the engines opened the b file, Stockfish thought that Leela castled its king too soon. Then Leela half opened the f file and gave a rook for a knight, Stockfish's eval jumped yet Leela's eval was still stable. Stockfish surprised Leela on move 21, after two moves without thinking Leela spent 4 minutes to consider its reply and its eval also jumped. 

The engines played out a long PV agreement, most pieces were exchanged and the game reached a QRN vs QR position on move 31. Leela was two pawns up but with such high evals it was clear both engines knew Stockfish was winning.

The white king only had a knight as cover but Leela could not attack it. Stockfish quickly captured a pawn and created a passer. After exchanging rooks Stockfish attacked the black king and captured two more pawns. The white passers advanced and Leela lost its queen, the game ended in a tablebase win.

Season 25 premier division, after RR6

Standings after RR6

Stockfish is still perfect with bias (usually as white, one game as black), it lost a game against Stoofvlees but drew the game pair. Leela had 4 game pair wins against the bottom5, it drew the game pair against KomodoDragon. KomodoDragon won 3 game pairs against the bottom5, its 3rd place is secure. Both Ethereal and RubiChess lost two game pairs against the top3, Ethereal won two game pairs while RubiChess won only one and lost one. As a result Ethereal is in 4th place 0.5 points ahead of RubiChess.

Interesting games

game 114, Ethereal - KomodoDragon: KomodoDragon was up a pawn but Ethereal developed its pieces faster. Ethereal gave a knight and attacked the black king, KomodoDragon exchanged queens and gave the piece back. Ethereal had an advanced passer and KomodoDragon gave a knight to stop it, the game reached a RBN vs RN position. The engines cleared the king side pawns, KomodoDragon tried to keep its pieces safe, Ethereal hunted the black king and mated.

game 121, Ethereal - Igel: Ethereal castled long and pushed pawns on the king side. Igel exchanged minor pieces and the game reached a QRR vs QRR position, Ethereal gave a pawn and opened files on the king side. Both the black king and queen became targets, Igel tried to exchange pieces but Ethereal managed to avoid this. Ethereal forced a rook for queen exchange, then Igel lost more material an dthe game ended just before mate.

game 122, Stockfish - SlowChess: There were many early exchanges that opened the center, material was equal but evals kept increasing. The game reached a RBN vs RBN position, SlowChess had two isolated pawns on the queen side and Stockfish captured both after a while. SlowChess gave a knight for a passer, it left another passer alone, I'm not sure why. SlowChess lost the bishop for the passer, Stockfish gained more material and mated.

game 125, Igel - RubiChess: There were no exchanges after the start, the engines formed long pawn lines in the center and king side. Igel's eval jumped after RubiChess opened the a file and Igel went a pawn up. All rooks were exchanged, then Igel closed the hole in its pawn wall with a bishop. RubiChess could only wait as Igel prepared its pieces. When it was ready Igel moved the bishop and a series of exchanges reduced to a BN vs BN position. The white king moved forward, after exchanging bishops Igel captured 3 more pawns. Igel queened a passer and mated.

game 129, Stockfish - Igel: Igel captured a pawn and the engines opened the queen side, Igel preferred to keep its king in the center. Stockfish opened files on the queen side and regained the pawn. It attacked the black king, then exchanged queens and captured two pawns. The game reached a double rook ending, Stockfish pushed two passers forward. Igel captured one and lost a rook for the other, game over.

game 130, Stoofvlees - Ethereal: The black king moved without castling and the king side rook couldn't develop. The engines opened the queen side and both engines created a passer there. Stoofvlees opened the king side and its major pieces threatened f7 and the black king. Ethereal gave the f pawn, Stoofvlees created two more passers and then captured the black passer. The engines reduced to a RB vs RB position, Ethereal stopped the white passers but lost material, the game ended in a tablebase win.

game 131, Leela - SlowChess: Leela was up a paws early, the engines reduced to a QRB vs QRN position. SlowChess regained the pawn but evals kept increasing. SlowChess couldn't defend against all threats and Leela captured a pawn, then created connected passers. Leela captured another pawn and exchanged queens, SlowChess captured a passer but lost its knight. The game ended in a tablebase win. 

game 136, Stockfish - Stoofvlees: Stoofvlees gave a knight and attacked the white king, Stockfish gave material back to let its king escape to the center, leading to a BN vs R imbalance. The black queen moved forward and Stoofvlees pushed a passer, Stockfish gave 3 pawns and its queen moved forward to counter attack. Stockfish ignored the black passers and moved a rook to the back rank. It traded RB for Q and then chased the black king and mated.

game 137, Stoofvlees - Igel: Most minor pieces were exchanged early, the game reached a RRB vs RRN position. Stoofvlees had a passer on the queen side, Igel exchanged a pair of rooks and captured the passer but Stoofvlees created another. Stoofvlees captured a pawn and added a second passer, the white king moved forward and Igel couldn't prevent a queening. The game ended in a tablebase win.

Standings after RR5: Stockfish +16, Leela +7, KomodoDragon +2, Ethereal 0, RubiChess -1, Stoofvlees -3, Igel -8, SlowChess -13. Stockfish continues to be perfect with bias, it drew against RubiChess in white but in a black biased opening. Leela drew against RubiChess while  KomodoDragon drew against SlowChess and lost against Ethereal. RubiChess had a weak RR with no wins and one loss, Ethereal is back in 4th place.

game 142, KomodoDragon - Ethereal: Ethereal was a pawn up while KomodoDragon had a development advantage. KomodoDragon castled long, most minors were exchanged and the game reached a QRN vs QRN position. KomodoDragon captured two pawns on the queen side and Ethereal finally castled its king. KomodoDragon slowly pushed passers forward keeping its king safe. Ethereal started to lose material and the game ended in a tablebase win. There were two white wins in this game pair.

game 143, RubiChess - Stockfish: Stockfish was a pawn up, (negative) evals started to increase after move 20. The game reached a RBN vs RBB position, RubiChess gave another pawn to weaken the black pawn structure, creating black doubled passers on the queen side. RubiChess captured 2 black pawns, then traded its rook for the black bishop pair. Ethereal a passer on both sides of the board, RubiChess captured one but lost its bishop. Stockfish queened the second passer and mated.

game 144, Leela - Stoofvlees: Evals were stable and slightly drifting down until move 30. The engines exchanged queens, the white bishop pair was very effective in the open board. Leela captured a pawn and reduced to a RBB vs RBN position, then it traded a pair of bishops and captured the last remaining black pawn. Stoofvlees couldn't stop the white passers, it lost material and the game ended in a tablebase win. 

game 145, Leela - Igel: Leela castled long and opened the g file, Igel surrounded its king with pieces. Evals were drawish until move 32, the engines exchanged all rooks and evals started to increase. The game reached a QBN vs QBN position, Leela had a pawn majority on the queen side and the black pieces were far. Leela gave its two minor pieces and queened, after exchanging a pair of queens the game ended in a tablebase win.

game 147, Stockfish - KomodoDragon: The center was blocked, Stockfish pushed pawns on the king side and placed one on h6, trapping a black bishop in the corner. Stockfish castled short, There was a lot of shuffling on the queen side but evals increased very slowly. On move 41 the engines exchanged a pair of rooks, the first piece exchange of the game. For a long time Stockfish threatened the black b5 pawn while KomodoDragon defended it. On move 78 KomodoDragon decided to give its trapped bishop for a pawn, 10 moves later Stockfish finally captured the b5 pawn and created a passer. KomodoDragon blocked the passer but Stockfish captured more pawns. KomodoDragon lost more material, Stockfish queened and mated.

game 148, Ethereal - SlowChess: Ethereal pushed a pawn to h6 and trapped a black bishop. After a while Ethereal went a pawn up, then SlowChess gave another pawn and Ethereal had a passer. SlowChess exchanged its corner bishop and all rooks, it captured the h6 pawn but couldn't stop the white passer. Ethereal gave its queen for a knight and queened the passer, in a QBB vs QN position SlowChess lost more material, Ethereal queened again and mated.

game 151, KomodoDragon - Stoofvlees: Both engines castled long, exchanges opened the center. After a series of exchanges the game reached a rook ending with white a pawn up. Stoofvlees had 3 isolated pawns, eventually KomodoDragon captured one and reduced to a tablebase win. 

game 155, Stoofvlees - SlowChess: Stoofvlees moved its queen forward on the king side, SlowChess gave a pawn to open the h file and castled long. SlowChess traded queens and gave a rook for a bishop, the game reached a RR vs RB position. Both engines still had 6 pawns and the rooks were limited, for a while the engines shuffled. On move 53 Stoofvlees managed to exchange a pair of pawns and open files, one rook moved to the back rank. Stoofvlees went a pawn up and created a passer, then reduced to a winning rook ending.

game 156, Stockfish - Ethereal: The g file was half open, Stockfish placed a rook there and castled long. There were no exchanges for a while and evals slowly increased, on move 40 Stockfish started to open the board. After a series of exchanges the game reached a B vs N ending with white two pawns up and a passer on the 7th rank. The white king moved forward, Ethereal captured one passer but couldn't block two more, Stockfish queened and mated.

game 158, Ethereal - Stoofvlees: There were many early exchanges and the game reached a RBN vs RBN position with black a pawn up. Evals were stable and drifted down, Ethereal moved its rook forward and regained the pawn. Stoofvlees created a passer and pushed it forward when Ethereal's eval jumped. Stofvlees moved instantly 3 times, when it stopped to think its eval jumped as well. Ethereal prepared a beautiful trap for the black rook, after exchanging rooks it captured the isolated black pawns. After capturing the black passer Ethereal pushed its own passers forward, it queened and mated. There were two white wins in this game pair. 

game 160, KomodoDragon - RubiChess: There were only a few exchanges after the start and the engines shuffled for a long time. On move 81 KomodoDragon started to open the king side and evals increased. RubiChess captured a pawn and created a passer on the queen side but its king was in danger. KomodoDragon captured two pawns and created passers, then captured the black passer and reduced to a QRB vs QRB position. RubiChess lost material for white passers, then because of a mate threat and finally KomodoDragon mated.

game 161, KomodoDragon - Igel: There were only a few exchanges after the start, evals increased very slowly. On move 35 evals jumped, in a series of exchanges KomodoDragon opened the king side and attacked with its major pieces. The game reached a QRR vs QRR position and KomodoDragon captured two pawns, then reduced to a tablebase win.

game 162, RubiChess - SlowChess: The center was blocked and there were only a few exchanges after the start. The first pawns were exchanged on move 23. RubiChess managed to created an advanced  passer in the center and then captured a pawn. The engines exchanged pieces and reduced to a rook ending. RubiChess connected a second passer in the center, SlowChess lost its rook and the game ended in a tablebase win.

game 163, Leela - Ethereal: There were only a few exchanges after the start, Ethereal doubled rook and queen on the half open g file and threatened the white king. Leela's eval jumped when it gave a bishop and trapped the black queen. Ethereal exchanged queens and lost a rook. The game reached a RR vs RN position, Leela had a passer on the king side and Ethereal created a passer on the queen side. Leela managed to stop the black passer on the 2nd rank, it used a mate threat to capture the black knight. The game ended in a tablebase win.

game 164, Stoofvlees - Stockfish: Stoofvlees opened the king side and captured a pawn. Stockfish exchanged queens and a pair of rooks, both kings were safe. The attention moved to the queen side, the engines cleared the pawns there. Stoofvlees captured another pawn and created a passer in the center. The game reached a RBN vs RBN position, the black king moved forward to block the king side. After exchanging bishops Stoofvlees trapped the black king on the h file and pushed passers in the center. Stockfish couldn't prevent a queening, the game ended in a tablebase win. There were two white wins in this game pair. 

game 165, Igel - Stoofvlees: The engines exchanged minor pieces and the game reached a QRR vs QRR position. Igel went a pawn up, Stoofvlees captured two pawns back and the engines reduced to a rook ending. Despite being a pawn down the white passers were faster and Igel kept the black king away from them. Stoofvlees captured another pawn and pushed a passer to the 2nd rank, but it was not enough. Igel queened first and mated the exposed black king. There were two white wins in this game pair.

game 166, Stockfish - Leela: see featured game below.

Featured game: Stockfish - Leela
game 166

The black queen was out early, Leela avoided a queen exchange. Stockfish castled long, then used a knight to fork the black queen and capture a pawn. Leela tried to compensate by opening the long diagonal as a threat to the white king.

Evals slowly increased though the engines shuffled for a few moves. Then the engines played out a long PV agreement, Stockfish gave a rook for a bishop, the engines continued to exchange pieces until reaching a rook ending with white still a pawn up.

The white king moved forward to the center. After a while Stockfish exchanged pawns on the king side and created a passer. The white king captured the black pawns on the queen side, mate was in the PV when the game ended in a tablebase win.

Season 25 premier division, after RR4

Standings after RR4

Stockfish continues to dominate the premier division. It lost a game against Leela and won the reverse game, but it had 6 game pair wins against the other engines. Leela in 2nd place had a weak DRR with 3 game pair draws against lower ranked engines, including an unusual loss on time against SlowChess. KomodoDragon had a slightly better second DRR with 3 game pair wins, it is more secure in 3rd place. The closest race is between Ethereal and RubiChess for 4th place.

Interesting games

game 59, Stockfish - RubiChess: There were no exchanges after the start until queens were exchanged on move 23, followed by the first pawn exchange. The engines mostly shuffled though evals gradually increased, Stockfish had a space advantage and a bishop pair. On move 48 Stockfish opened the king side, RubiChess gave a rook for a bishop and reduced to a RBN vs BNN position. Stockfish created an advanced passer, RubiChess lost a knight for it. RubiChess lost more material and was mated.

game 62, RubiChess - Stoofvlees: Both engines castled long, there was some shuffling after the start and then Rubihess gave a knight for two pawns and exposed the black king. Stoofvlees surrounded its king by pieces, it missed something in a complicated position full of threats and pins and evals started to jump. In a eries of exchanges RubiChess gave a rook for a knight, the black king had less protection. This allowed RubiChess to reduce to a QB vs RR ending two pawns up. Stoofvlees couldn't protect its king, it lost pieces and was mated.

game 66, Stockfish - SlowChess: Stockfish was a pawn up from the start, evals started to increase after move 20 and Stockfish placed a strong bishop on d5. SlowChess mostly waited, after opening the b file Stockfish exchanged its bishop and placed a rook on d5, then captured another pawn and created a passer. SlowChess beame desperate, it gave two more pawns to open the king side,now it faced more passers and couldn't get rid of any of them. Stockfish attacked the black king, SlowChess lost material and was mated.

game 68, Leela - RubiChess: There were only a few exchanges after the start and evals were stable. On move 29 Leela captured a pawn and evals started to increase. RubiChess opened the queen side and tried to attack but wasn't strong enough, Leela exchanged pieces and in a QRB vs QRN position  captured a second pawn. After exchanging queens Leela created a passer, progress was slow but inevitable, it took Leela another 40 moves to queen a pawn and mate.

game 70, KomodoDragon - Leela: Most minor pieces were exchanged quickly and Leela castled long, KomodoDragon managed to create an advanced passer in the center. Leela was concerned with protecting its isolated pawns on the king side and only blocked the white passer. KomodoDragon's eval started to increase while Leela'a remained stable. KomodoDragon captured pawns on the king side, then gave its rook and attacked the black king. Leela's eval started to increase when it was 5 pawns down in a QN vs QRN position. Leela captured a few pawns back but lost its knight for a passer. After exchanging queens the N vs R ending 3 pawns up was a win, though it took KomodoDragon another 35 moves to complete.

game 73, Stockfish - Igel: Igel gave two pawns and opened the king side, Stockfish kept its king safe and evals started to increase. The game reached a RB vs RB position, Stockfish was a pawn up with connected passers. Stockfish pushed the passers forward and exchanged rooks, the bishops were same colored. Igel captured 3 pawns but couldn't stop a queening and mate.

game 75, Leela - SlowChess: There were no exchanges after the start, the engines formed long pawn lines across the board. SlowChess opened the h file, Leela walked its king to the queen side. Leela's eval was very high though SlowChess moved its queen and a rook forward. SlowChess gave a knight for two pawns and created connected passers on the king side, Leela exchanged pieces and gave back a bishop to capture the passers. Leela captured a pawn and created an advanced passer, SlowChess lost a bishop for th epasser and the game reached a RBN vs RN position. SlowChess lost more material and the game ended in a tablebase win. 

game 80, Stockfish - Stoofvlees: Stockfish castled long and pushed pawns on the king side. Evals increased, a series of exchanges opened the king side and Stockfish gave a bishop and two pawns for a rook. Stockfish used its major pieces to attack, first it sacrificed a rook and exposed the black king, the it captured a bishop. The white queen and rook chased the black king and forced mate.

game 81, Stoofvlees - Igel: Evals were stable until move 39, Igel missed something and evals jumped. Stoofvlees opened the d file, then in a series of exchanges the engines reduced to a B vs R ending. Stoofvlees was only one pawn up but it pushed a passer to the 7th rank. It used a second passer to open the way for the white king to move forward. Stoofvless captured a pawn and created another passer, Igel lost its rook to stop it. Stoofvlees had one last pawn to win. 

game 82, Leela - Stockfish: Queens were off early, evals were stable, Stockfish created a passer in teh center and the white king moved to block it. Stockfish placed a knight on c3 that interfered with the white piece movement, but was also trapped there. Leela moved its attention to the king side and evals increased. Leela managed to capture a pawn and create a passer, then it used exchanges to create two more. Stockfish couldn't stop all the passers and it lost a rook, the game ended in a tablebase win.

game 83, RubiChess - Ethereal: Both kings remained in the center uncastled, Ethereal had difficulties to develop its king side pieces but eventually the h file opened and the engines exchanged a pair of rooks. RubiChess moved its queen forward on the king side, Ethereal was busy defending and couldn't attack the exposed white king. The engines reduced to a RB vs RB position, RubiChess captured a pawn and created a passer. Ethereal delayed but couldn't stop the passer, it lost a rook and the game ended in a tablebase win.

game 84, KomodoDragon - SlowChess: KomodoDragon pushed a pawn to h6, it moved its king without castling. A series of exchanges opened files on the queen side and evals started to increase. The engines shuffled for a while, KomodoDragon placed its major pieces o the open files, then it gave a rook for a bishop and attacked. The game reached a RB vs RR position with the black king in the corner and a white rook on g7. The white king moved forward and the engines traded pawns, SlowChess lost a rook for a passer and the game ended in a tablebase win.

Standings after RR3: Stockfish +10, Leela +6, KomodoDragon +3, RubiChess -1, Ethereal  -2, Stoofvlees -3, Igel -5, SlowChess -8. Stockfish lost the game in black against Leela, it continues to be perfect in white. Leela won its 3 white games, including against Stockfish, but lost in black against KomodoDragon. KomodoDragon had a good RR3 with a +2 score, compared to a -1 score in RR1.

game 85, Igel - SlowChess: Igel pushed pawns on the king side with evals increasing steadily. After opening the g file the white queen moved forward through the center, in a series of exchanges Igel captured a bishop and reduced to a RN vs R position. Igel had enough pawns, the game ended in a tablebase win.

game 89, Leela - Igel: The engines castled in opposite directions and Leela pushed pawns on the king side. The engines exchanged minor pieces in the center, Leela captured a pawn and created a passer. Igel captured the passer and in a series of exchanges the game reached a QRR vs QRR position. Leela again had a passer that it slowly pushed forward. After reducing to a rook ending Leela captured a pawn and had 2 passers on the 7th rank, it forced a queening and won.

game 91, Stockfish - KomodoDragon: see featured game below

game 92, Ethereal - SlowChess: The king side was open and both engines castled long. Evals increased steadily though SlowChess moved a rook forward and captured a pawn. Queens were exchanged and Ethereal regained the pawn, then it exchanged pieces and captured two more pawns. The game reached a RB vs RB position, Ethereal slowly pushed a passer forward and SlowChess lost the bishop to stop it. The game ended in a tablebase win.

game 95, KomodoDragon - Stoofvlees: The engines opened the h file and exchanged a pair of rooks early. Both engines castled long and the game reached a QRB vs QRN position. KomodoDragon captured a pawn and created a passer on the king side. Stoofvlees thought it was safe for a few moves after exchanging the minor pieces, it even captured two pawns. However when it stopped to think it realized it was losing. KomodoDragon pushed the passer to the 7th rank, then pinned the black rook. Stoofvlees couldn't get out of the pin, a white pawn moved forward and captured the rook, mate followed.

game 98, Leela - KomodoDragon: KomodoDragon castled long, Leela moved a bishop forward and captured a pawn. KomodoDragon moved its major pieces to the king side but was not strong enough to attack, Leela exchanged pieces when it could and evals increased. Leela gave two pawns and opened the queen side, then traded RN for Q. In a QB vs RBN position Leela captured pawns and went two pawns up. It pushed a passer, gave its queen for a bishop and queened the passer. KomodoDragon lost material and was mated. There were two white wins in this game pair.

game 99, Stoofvlees - SlowChess: Stoofvlees castled long, SlowChess pushed pawns on the queen side and its king remained in the center. Stoofvlees tried to open the king side but SlowChess avoided exchanges until its king walked to the queen side. After opening the king side the engines traded pawns and Stoofvlees went a pawn up. The engines exchanged a pair of rooks and Stoofvlees moved a rook to the 7th rank. In a series of exchanges the engines reduced to a Q vs RN position, SlowChess lost the roo for a passer and the game ended in a tablebase win.

game 100, Stockfish - Ethereal: The engines exchanged all knights, the queen side was open and Stockfish captured a pawn on the king side. Ethereal gave a rook for a bishop and pushed pawns in the center, after exchanging queens evals started to increase in a RRB vs RBB position. Ethereal stopped a white passer and regained the pawn, after exchanging a pair of bishops Ethereal had a passer in the center and Stockfish had two on the king side. Stockfish gave one passer but trapped the black king on the open h file. It used the threat of mate to gain material and win.

game 102, Ethereal - Stoofvlees: The engines exchanged pawns on the queen side, Ethereal's eval jumped when it gave a knight and created a passer. Stoofvlees thought it was fine for a few moves, then its eval jumped as well. Ethereal regained the piece and the game reached a RRN vs RRN position. Ethereal gave a rook for a knight and pawn, then the white king moved forward on the king side. Stoofvlees captured the passer on the queen side but could not defend the king side. After a pairof rooks was exchanged Ethereal queened a passer and mated.

game 103, SlowChess - Leela: The engines started to shuffle on move 30, with piece exchanges resetting the 50-move counter. Leela was out of time and playing on the 6 second increments, on move 152 Leela moved too late and lost on time.

game 105, KomodoDragon - Igel: Both engines did not castle their kings, there were almost no pawn exchanges after the start and both engines played behind their pawn lines. Igel placed both knights on the 4th rank and tried to hold a pawn line across the board. KomodoDragon exchanged a bishop for one of the black knights, then moved pieces to the queen side where the black king was located. The engines opened the queen side with exchanges, KomodoDragon captured two pawns and then moved it major pieces forward on the king side. The game reached a QR vs QR position with the black king on the run and a white 3 pawns up. Igel lost its queen for a rook, KomodoDragon queened a passer and mated.

game 106, RubiChess - SlowChess: Both engines castled long, evals started to increase on move 20 after SlowChess created an advanced passer in the center while RubiChess had a pawn majority on the king side. RubiChess moved a rook forward on the king side and exchanged queens, then reduced to a RBN vs RBN position. RubiChess captured the black passer and was 3 pawns up, it gained material and the game ended in a tablebase win.

game 110, Stockfish - Leela: Evals were stable for a long time, the engines exchanged pawns and a few minor pieces. On move 32 the engines opened the queen side and evals started to increase slowly. Stockfish doubled rooks on the open c file, then created an advanced passer after an exchange. After some shuffling Stockfish gave a rook for a knight and the game reached a QRB vs QRR position. Leela couldn't get rid of the white passer, Stockfish captured two pawns and the queens were exchanged. Leela tried to delay but Stockfish was patient, eventually Leela couldn't stop the white passer, Stockfish queened and mated. There were two white wins in this game pair.

Featured game: Stockfish - KomodoDragon
game 91

Stockfish pushed pawns on the king side and castled long. it gave a pawn and opened the king side. The black king remained in the center and evals slowly increased. KomodoDragon had a rook on the open h file, Stockfish regained the pawn, then the engines exchanged a pair of rooks and queens. On move 40 Stockfish went a pawn up, its first material advantage of the game. 

Stockfish had one passer, still on its initial square. Progress was slow in a difficult middlegame, the black bishop pair was strong in an open board. KomodoDragon wanted to separate the white pawns on the queen side, on move 54 it gave a rook for a knight and captured the b pawn. In a RBN vs BBN position KomodoDragon blocked the white passer and Stockfish captured a pawn. 

Progress was again slow, pushing the passer required a lot of preparation. On move 72 Stockfish pushed the passer the the 5th rank, on move 78 Stockfish gave back the rook for a bishop but then its passer was unstoppable. Stockfish queened the passer and mated.

Season 25 premier division, after RR2

Standings after RR2

Stockfish had a perfect DRR with 7/7 game pair wins, Leela was perfect against the bottom5 engines but lost to Stockfish and drew against KomodoDragon. So far it is not clear whether to include KomodoDragon in the leader group, it only had 2/5 game pair wins against the bottom5 engines. At the bottom SlowChess is the only engine without a game pair win so far. RubiChess advanced from league 1 and it may be strong enough to stay in the premier division this season.

Interesting games

game 3, Stockfish - RubiChess: The engines castled in opposite directions, RubiChess gave a pawn and tried to attack the queen side. Stockfish moved pieces to protect its king, RubiChess decided to give a bishop for pawns and expose the white king. It then gave a rook for a bishop to clear the last white pawn on the queen side. Stockfish found safety for its king with a pair of knights blocking files. After exchaging queens the attack was over and Stockfish was a rook up, RubiChess lost more material and was mated.

game 6, RubiChess - Stoofvlees: RubiChess captured a pawn on the queen side, Stoofvlees tried to attack on the king side. RubiChess was strong enough to keep its king safe but Stoofvlees did not change its plan. RubiChess captured 3 more black pawns and gave a rook for a bishop. Stoofvlees gave pieces to expose the white king, RubiChess avoided perpetual check and forced mate on the other side of the board.

game 9, Ethereal - Igel: Ethereal gave a pawn and that was the only capture after the start. The engines shuffled with stable evals until move 51, Igel gave the pawn back and the first pieces were exchanged on move 58. Evals started to increase a few moves later, after some more exchanges Ethereal was a pawn up with a passer on the queen side. Twice Ethereal left a piece hanging and Igel refused to take, probably related to king safety. Evals continued to increase, Ethereal opened the king side and captured two pawns. Igel couldn't protect its king and block passers without losing material, Ethereal queened and mated.

game 10, Stockfish - SlowChess: There was one pawn exchange after the start and the engines played mostly behind their pawn lines. Evals slowly increased, then jumped when Stockfish gave a bishop for pawns and exposed the black king. SlowChess exchanged pieces and stopped the attack, the result was a BN vs pawns position. Stockfish captured the black passers and the game ended in a tablebase win.

game 12, Leela - RubiChess: Leela gradually increased the pressure on the king side while evals increased, eventually the black king was left without pawn support. The game reached a QRB vs QRB position, Leela went a pawn up and exchanged queens. RubiChess couldn't stop the connected white passers advancing, Leela queened and mated.

game 15, SlowChess - Stoofvlees: SlowChess castled long, Stoofvlees pushed pawns on the queen side and tried to attack. It gave a knight for pawns and opened the center files but SlowChess kept its king safe. SlowChess moved its rooks forward and countered with an attack on the black king. Stoofvlees lost material and the game ended in a tablebase win.

game 17, Stockfish - Igel: The center was blocked and both engines castled long. Igel struggled to develop its king side pieces, it gave a knight for a pawn to open the queen side. Stockfish gave a rook to get rid of a strong knight, Igel's DS bishop finally moved and was exchanged. Stockfish captured a pawn, then used a pawn majority on the king side to create an advanced passer. After exchaging queens Igel was forced to lose material for the passer, the game reached a winning RB vs R ending.

game 18, Stoofvlees - Ethereal: There were many early exchanges and the game reached a RRB vs RRB position. Evals started to increase though material was equal, all rooks were exchanged and Stoofvlees captured a pawn. Ethereal tried to cover threats on both sides of the board and Stoofvlees captured the pawns in the center, the game ended in a tablebase win.

game 19, Leela - SlowChess: The engines opened the center, Leela gave a pawn but its bishops had a clear view of the king side corner. SlowChess tried to protect its king, Leela gave another pawn and then regained it and created an advanced passer in the center. SlowChess tried to counter with its passers, but it had to defend against a pawn on the 7th rank and its king was under threat. SlowChess lost material and the game ended in a tablebase win.

game 20, RubiChess - KomodoDragon: KomodoDragon castled long, RubiChess opened the a file and doubled its rooks there. For a long while the engines shuffled with stable evals, after move 75 the engines started to exchange pieces and pawns. KomodoDragon gave a rook for a knight and evals started to increase. The game reached a RB vs BN position, after trading most pawns RubiChess had two doubled pawns and KomodoDragon had one. KomodoDragon defende its last pawn and avoided a 7-man tablebase loss. RubiChess pushed the black king to the back rank, moved its king forward and mated.

game 24, Stockfish - Stoofvlees: Evals slowly increased and Stockfish went a pawn up. Stoofvlees gave a knight and tried to attack through the center. Stockfish gave the pieces back but it was two pawns up. The white king was exposed in the center but Stoofvlees' attack was not strong enough, the game reached a RRB vs RRB position with white 3 pawns up and ended in a tablebase win.

game 25, Stoofvlees - Igel: The engines castled in opposite directions, Stoofvlees opened the king side and the game reached a QRR vs QRR position. Stoofvlees captured a pawn, Igel thought it was quite safe until queens were exchanged. Stoofvlees managed to capture another pawn and get its king forward. It pushed a passer to the 7th rank and Igel lost a rook for it. The game ended in a tablebase win.

Standings after RR1: Stockfish +4, Leela +2, Ethereal RubiChess 0, KomodoDragon SlowChess Stoofvlees -1, Igel, -3. Stockfish and Leela have an early lead, the only engines with a positive score and no loss so far. Stockfish won all its games in white in the RR, Leela had one less game in white and one of those was a draw against Stockfish. KomodoDragon lost a game against RubiChess and has no wins, but 2/3 of its games in white were against the leaders. It may still move up in the table, though it's too early to tell. We may not have a top3 this season but a top2. 

game 29, Igel - SlowChess: Evals increased after move 20, the game reached a RRN vs RRB position. Igel captured a pawn and also pinned the black bishop. SlowChess couldn't get out of the pin, eventually Igel captured the bishop. Igel captured the remaining black pawns for the knight, the game ended in a tablebase win.

game 30, KomodoDragon - Ethereal: KomodoDragon captured a pawn and created a pawn majority on the queen side. The white king was castled long, Ethereal moved major pieces to threaten an attack, after a pawn exchange KoodoDragon had connected passers. Evals gradually increased as KomodoDragon exchanged pieces, the game reached a RBN vs RBB position. KomodoDrago reduced to a same colored bishop ending, Ethereal lost the bishop for a passer and the game ended in a tablebase win. 

game 32, Leela - Stoofvlees: Leela captured a pawn and the game reached a RBN vs RBN position. Stoofvlees regained the pawn but its knight was far on the king side almost trapped. By the time Stoofvlees moved the knight back Leela cleared the black pawns on the queen side. Both engines had passers, after reducing to a knight ending there was a promotion race. Stoofvlees was a pawn up but Leela queened first followed by mate.

game 33, Leela - Igel: The engines opened the queen side and evals started to increase. After the g file opened Leela had time to move its king away from the king side while Igel dealt with potential threats on its back rank. After exchanging queens Leela captured a pawn and created a passer in a RBN vs RBN position. Igel lost material and the game ended in a tablebase win.

game 35, Stockfish - KomodoDragon: There were only a few exchanges after the start, Stockfish captured a pawn on the queen side and KomodoDragon tried to attack on the king side. KomodoDragon opened the g file and doubled its rooks there, Stockfish exchanged a pair of rooks and kept its king safe. After more piece exchanges the game reached a RNN vs RBN position, Stockfish created a passer and KomodoDragon gave a knight to stop it. Stockfish captured more pawns, queened a passer and mated.

game 36, Ethereal - SlowChess: Ethereal created a passer on the queen side and SlowChess created a passer in the center. After exchanging queens SlowChess gave its bishop to capture the white passer, Ethereal captured the black passer and reduced to a RBN vs RN position. Ethereal captured pawns, SlowChess lost its rook for a passer and the game ended in a tablebase win.

game 37, Igel - Ethereal: Igel trapped a black knight on the king side, then captured a pawn on the queen side and created a passer. Evals increased though there were no exchanges, the first pieces were exchanged on move 40. Igel moved a rook forward and pushed the passer, Ethereal freed its knight and it crossed the board. The game reached a BN vs BN position, Ethereal lost the knight for the passer. Ethereal avoided a 7-man position, Igel queened a passer and mated. There were two white wins in the game pair.

game 43, Stoofvlees - SlowChess: Stoofvlees castled long, SlowChess pushed pawns on the queen side but slowly and without pieces to back them. One pawn reached a3 and the rest were blocked. Evals started to increase, SlowChess captured a pawn and then Stoofvlees captured two. The b file opened but Stoofvlees walked its king to the king side for safety. SlowChess gave a rook for a bishop and the a pawn became an advanced passer, the game reached a RRB vs RNN position. While SlowChess protected its king and passer Stoofvlees pushed connected passers forward. Stoofvlees captured the black a pawn and pushed a 3rd passer, SlowChess lost material and the game ended in a tablebase win. There were two white wins in this game pair.

game 44, Stockfish - Ethereal: There was a lot of shuffling after the start, the first piece exchange was on move 35. Stockfish had a bishop pair advantage, evals started to increase after move 48. Ethereal captured a pawn and opened the center, the game reached a QRB vs QRN position, Stockfish regained the pawn and created a passer. The engines reduced to a queen ending, Stockfish kept its king safe and pushed a passer forward, the game ended in a tablebase win.

game 46, Ethereal - Stoofvlees: There were many early exchanges and the game reached a QRN vs QRN position. Ethereal's evals started to increase, Stoofvlees saw the problem a few moves later. Ethereal moved its pieces forward to attack the black king, in a series of exchanges the engines reduced to a king and pawns ending. Each engines had 3 pawns, Ethereal's two connected pawns on the king side forced the black king to move there, leaving the black pawns on the queen side unprotected, game over. There were two white wins in this game pair. 

game 48, KomodoDragon - RubiChess: Both engines castled long, evals slowly increased though RubiChess captured a pawn. KomodoDragon increased the pressure on the queen side and then gave a rook for a bishop and pawn to open the b file. The black king ran to the king side, after a series of exchanges RubiChess gave back the material and the game reached a RBN vs RNN position. KomodoDragon pinned a knight on the back rank and then it captured the knight. The game reached a tablebase win 20 moves later. There were two white wins in this game pair. 

game 49, KomodoDragon - Igel: There were no exchanges until the engines opened the king side on move 25, KomodoDragon went up a pawn and evals started to increase. Igel had strong pawns in the center but its king was exposed. KomodoDragon had passers on the queen side, in a series of exchanges Igel lost a bishop and all the queen side pawns were cleared. KomodoDragon attacked the black king, Igel had a passer on the 7th rank but was not on time to stop being mated.

game 50, RubiChess - SlowChess: SlowChess pushed pawns on the queen side, after exchanging queens SlowChess created a passer there while RubiChess created a passer in the center. RubiChess blocked the black passer and moved its rooks forward, then captured a pawn and pushed the passer to the 7th rank. SlowChess lost its passer and another pawn, then lost a piece for the white passer and the game ended in a tablebase win. 

game 51, Leela - Ethereal: The white king was unable to castle, yet after Ethereal opened the d file evals slowly increased. The black queen moved forward on the king side but Leela kept its king safe. There was some action on the queen side, the b file opened and Ethereal created a passer. Then on the king side the h file was half opened, the black queen had to stay there to stop potential attacks. Leela had an advantage on the queen side, it captured a pawn and created a passer. Leela gave a rook for a bishop and captured the remaining black pawns on the queen side, then pushed its passer to the 7th rank. Ethereal lost material and the game ended just before mate.

game 54, Stockfish - Leela: see featured game below.

game 55, Ethereal - RubiChess: The engines castled in opposite directions, evals increased from the start as Ethereal prepared an attack on the king side. RubiChess captured 3 pawns and gave a knight, the black king was safe but Ethereal reduced to a RBN vs RB position. Ethereal captured pawns and exchanged bishops, RubiChess had a passer on the 2nd rank but couldn't hold on to it. The game ended in a tablebase win.

Featured game: Stockfish - Leela
game 54

Evals were stable for a long time after the start. Stockfish castled long and pushed pawns on the king side, one pawn reached h6. Leela pushed pawns on the queen side but eventually castled long as well. Leela captured a pawn, its king side rook couldn't develop for a while. After a pawn trade the white h pawn became as advanced passer. Leela freed its rook and Stockfish exchanged queens.

Stockfish's eval slowly increased while Leela's eval remained stable. Leela kept its rooks on the back rank to prevent a queening, Stockfish captured a pawn and exchanged a pair of rooks. In a RN vs RB position Stockfish traded pawns on the queen side. Material was equal and Leela was still not convinced.

Stockfish captured the black c pawn and pushed its passer to the 7th rank. Leela blocked with its rook and its eval started to increase. The white king and c pawn moved forward, when it was ready Stockfish abandoned its h pawn and captured the black a pawn. Leela couldn't stop the c pawn advancing, it lost material and the game ended in a tablebase win.

Season 25 league 1 statistics

A summary statistics table of previous stages and seasons. 

Draw rate, wins

Final draw rate was 47.7%. 

Game termination

The three most common game termination causes were:
39.0% - TCEC draw rule
39.0% - SyzygyTB
15.2% - Mate

There were 3 crashes in the stage, Seer crashed on time 3 times.

Moves per game

Median= 70.5
Average= 72.7

There were 31 games longer than 100 moves, the longest was 180 moves (DeepSjeng - Seer, game 21, draw). 

Time per game (hours)

Median= 1:04
Average= 1:03

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, 13.6% diverged immediately out of book, 53.0% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 20 plys (Seer - Viridithas, games 6 and 72, QGD Marshall defence, Seer won as white)