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.