Season 25 league 1

Final Standings

RubiChess and Igel advance to the premier division. RubiChess led from the start, it had two RRs with a perfect performance where it won all 6 games as white (with opening bias) and drew all 5 games in black (against opening bias). RubiChess beat all other engines at least once in a game pair, it had only two losses and won both reverse games. Several engines were in the race for 2nd place, though at the halfway point rofChade and Igel opened a gap to the rest of the field. rofChade was 2nd with a small margin, it also beat Igel in their first direct game pair. In the last RR rofChade lost a few games against lower ranked engines while Igel had its best RR with 6 wins including one against RubiChess. Igel's only loss was again to rofChade, but this time Igel managed to stay in the lead and hold on to 2nd place. 

The 4 engines that started in the entrance league did not advance further in season 25. DeepSjeng and Viridithas struggled in league 1 and both finished in the 4 bottom places destined for relegation - if there are no surprises in the next season. Caissa and Clover had better results but they couldn't keep up with the three leaders. They should start next season in league 1.

Seer crashed three times in the league, losing games on time. In one game it was losing anyway, but in two games against rofChade and Clover the position was drawn and Seer gifted wins by crashing. In the end this half point to rofChade did not change the race for 2nd place.

The two qualifiers will play in the premier division together with Stockfish, Leela, KomodoDragon, Ethereal, Stoofvlees and SlowChess, all played in the premier division of season 24. This season the premier division will be a 6DRR event, followed by a 4DRR playoff of the top 4 engines.

Interesting games

game 3, Revenge - DeepSjeng: The game reached a QRR vs QRR position, evals were mostly stable. All pieces were concentrated on the king side, DeepSjeng played inaccurately and Revenge exchanged all pieces. DeepSjeng realized it was losing the king and pawns (equal material) ending too late.

game 5, RubiChess - Clover: The center was blocked, RubiChess opened a file on the queen side and moved a rook to the 7th rank. The engines reduced to a RB vs RB position, RubiChess pinned the black bishop on the back rank and captured a pawn. Clover couldn't avoid losing more pawns and then its pieces, and finally mate.

game 6, Seer - Viridithas: By move 35 only one pair of pawns and a few minor pieces were exchanged. Seer attacked from the queen side and created connected passers in the center. Viridithas lost a bishop to stop the passers and the game reached a RB vs R position. Viridithas was 3 pawns up, Seer was careful to keep one last pawn. The game ended in a tablebase win 45 moves later.

game 11, rofChade - Revenge: The engines opened the center and exchanged pieces, the game reached a RB vs RB position with white a pawn up. Revenge thought it was quite safe until rofChade exchanged rooks. Revenge regained the pawn but its king was too far to help block a passer. rofChade won the black bishop for the passer and still had one pawn to win the game.

game 16, RubiChess - DeepSjeng: RubiChess was a pawn up, evals increased after move 30, then came back down after the game reached a QB vs QN position. DeepSjeng seemed to equalize and the engines shuffled for a while, but RubiChess' eval increased again. I'm not sure if DeepSjeng blundered or RubiChess found the right moves, RubiChess created a passer and exchanged queens. DeepSjeng lost the knight for the passer and the game ended in a tablebase win. 

game 17, Seer - Caissa: The center was blocked and there were only a few exchanges after the start. On move 49 Seer opened the h file, the black king ran to the queen side and Seer managed to capture a pawn and create an advanced passer. In a QRB vs QRN position Caissa lost its rook for the passer, the game ended in a tablebase win. 

game 18, Viridithas - Clover: The engines castled in opposite directions, Viridithas pushed pawns on the king side and created a passer in the center. The engines exchanged pieces and reduced to a RB vs RB position, Clover lost the bishop for the passer and the game ended in a tablebase win.

game 19, Igel - Clover: Most pieces stayed on the board, Clover moved its king without castling and the king side rook couldn't develop. After mover 45 the engines opened the board and exchanged pieces until only RB vs RB were left, Igel was a pawn up with an advanced passer. Clover exchanged rooks but Igel captured two more pawns, enough to win the opposite color bishops ending.

game 20, Caissa - Viridithas: The engines exchanged a few minor pieces and Caissa went a pawn up. The engines mostly shuffled for a while in a RBN vs RBN position, then the white king moved forward and Caissa created a passer. Caissa captured a second pawn and reduced to a winning N vs B ending.

game 27, RubiChess - ScorpioNN: After a series of exchanges in the center RubiChess was up a pawn with connected passers. ScorpioNN also had a passer but the white passers were stronger. RubiChess gave two minors to queen a passer, ScorpioNN gave material back to avoid mate and the end result was  QR vs QB position. ScorpioNN had a passer on the 2nd rank but its king was exposed and it was busy defending. RubiChess exchanged queens and captured the passer, then reduced to a winning king and pawns ending.

game 30, Clover - Caissa: The engines exchanged pieces until reaching a rook ending. Clover was a pawn up, it captured a second pawn to win.

game 31, Igel - Caissa: The black king remained in the center, Caissa developed its king side rook through the h file. Caissa gave the rook for a knight and attacked the white king, the engines reduced to a QB vs Q position with black 3 pawns up. Igel played patiently, it kept one pawn and forced a queen exchange. The game ended in a tablebase win after 25 moves.\

game 33, rofChade - Viridithas: Viridithas grabbed a pawn early but rofChade had a space advantage and evals increased gradually. rofChade pinned a bishop on the back rank, Viridithas gave a rook for a bishop to avoid losing a piece. The game reached a RN vs BB position, rofChade had an advanced passer and Viridithas lost a bishop to stop it. The game ended in a tablebase win.

game 34, ScorpioNN - Seer: ScorpioNN grabbed a pawn early, then created an advanced passer. Seer regained the pawn but gave a rook for a knight for the passer. Both engines created another passer, after some shuffling ScorpioNN captured the black passer on the 2nd rank. The game reached a RB vs BN position, ScorpioNN captured all the remaining black pawns, then mated after queening a pawn.

game 38, RubiChess - Revenge: The were a few exchanges after the start, evals slowly increased after move 30. RubiChess opened the queen side and gave a rook for a bishop to create an advanced passer. in a QRB vs QRR position RubiChess gave up that passer and switched to another one on the king side. Revenge lost material but couldn't stop the passer, game over.

game 41, Clover - rofChade: Queens were off early, all the rooks were on the a file with one black pawn between them. Clover moved a knight across the board to capture the pawn, with the king's help it managed to get the knight away safely. In a RBN vs RBB position Clover captured another pawn and queened a passer to win.

game 44, rofChade - Caissa: Caissa blundered when its queen moved forward to grab a pawn, it saw the next sequence of moves in its PV but thought it was safe. rofChade immediately attacked the black king, the game reached a QR vs QR position with black two pawns up but its king completely exposed. Caissa had to give its queen for a rook, the game ended in a tablebase win.

game 47, Revenge - Seer: With all pieces on the board Revenge traded minors, gave a pawn and opened the g file. Some of Seer's pieces were too far to help defend the king, Seer had to trade RN for Q. The engines exchanged pieces and the game reached a Q vs BR position, Seer lost the bishop for a passer and was mated.

game 49, RubiChess - Igel: Igel didn't castle its king, RubiChess opened files on the king side and center and threatened an attack with its major pieces. Igel exchanged pieces, the game reached a rook ending with white a pawn up. RubiChess had connected passers, Igel lost its rook for one, game over.

game 50, Seer - Minic: Seer traded a knight for 3 pawns, then reduced to a RN vs RBN position and captured a 4th pawn. After exchanging knights Minic was left without pawns, eventually Minic lost the bishop for a passer and the game ended in a tablebase win. 

game 54, DeepSjeng - rofChade: DeepSjeng went a pawn up and exchanged cleared the center. The white bishop pair controlled many squares, after a long shuffle DeepSjeng captured another pawn and reduced to a RBB vs RBN position. DeepSjeng captured a third pawn and rofChade couldn't avoid a queening, it gave away its pieces and was mated.

game 58, Revenge - Clover: Both engines castled long, then Revenge opened the a file. Revenge pushed a pawn to c6 and after exchanging queens moved both rooks to the a file. Clover captured pawns but had to give material to save its king. The game reached a RB vs B position with black 4 pawns up, Revenge captured pawns and queened its last one to win.

game 60, RubiChess - Seer: Queens were off early and the black king moved without castling. RubiChess attacked through the center and created a passer. Seer walked its king to safety, after a while RubiChess started an exchange series where it gave up the passer and reduced to a BN vs R position. RubiChess created another passer, this time Seer couldn't prevent a queening and mate.

game 64, Caissa - Revenge: After move 20 the engines exchanged pieces, Caissa went a pawn up and the game reached a RB vs RB position. The white king moved forward, after exchanging rooks Caissa captured another pawn and created a passer. Revenge blocked and captured the passer while Caissa captured the remaining black pawns to win.

Standings after RR1: RubiChess +6, Igel rofChade +2, Seer +1, Revenge Minic Caissa 0, Viridithas Clover -1, ScorpioNN -2, Fritz -3, DeepSjeng -4. RubiChess leads with a 2 point margin, it has won all games with the bias in white and drew against the bias in black. The fight for 2nd place is wide open, there were many decisive games and the reverse games may be significant. The 4 newcomer engines that started from the entrance league are not so strong in this league, this is probably their final appearance this season.

game 70, Caissa - Minic: Caissa gave a pawn and opened the center, the black king did not castle and the black king side rook was trapped. In a QRN vs QRN position Minic freed its rook while Caissa captured two pawns, then exchanged queens. After a while Caissa captured a second pawn and then created a passer that Minic couldn't stop without losing a piece, game over.

game 71, Clover - RubiChess: RubiChess was a pawn up while Clover attacked the uncastled black king. The game reached a RRN vs RRN position, Clover captured two pawns and created a passer. Progress was slow, after exchanging a pair of rooks Clover pushed the passer, after 30 moves it reached the 7th rank. Clover created a second passer and RubiChess couldn't stop both, Clover queened to win.

game 74, Seer - Clover: Clover equalized though it was a down a rook for a bishop. The game was heading for a draw in a QRB vs QBB position when Seer didn't move on time and lost.

game 75, RubiChess - Caissa: RubiChess gave two pawns and attacked the black king. It sacrificed a knight as well, and then regained the material in a series of exchanges and the game reached a RB vs RN position. Caissa gave a pawn to create a passer, the engines cleared the queen side pawns and exchanged minors. RubiChess blocked the black king away from the king side and pushed its pawns there, winning a rook ending with one pawn advantage.

game 83, Caissa - Seer: The center was blocked and there were no exchanges after the start. After move 29 a few pawn exchanges created passers in the center for both engines, evals started to increase. The first piece exchange was queens on move 44 and the engines cleared the center pawns. Caissa doubled rooks on the h file, Seer gave a rook for a knight to avoid a trap for its king. In a RRB vs RBN Caissa captured pawns, then slowly improved its position. Then on move 80 Seer lost on time, though it was probably losing in any case.

game 84, Clover - Viridithas: The engines gradually exchanged minor pieces, Clover captured a pawn and the game reached a QRB vs QRN position. After some shuffling Clover captured another pawn and a series of exchanges reduced to a B vs N ending. Clover queened a passer and then mated.

game 88, RubiChess - rofChade: RubiChess threatened the black king, rofChade started a series of exchanges that resulted in a RNN vs RN position. It took a while but RubiChess managed to create a passer and promote to a queen, followed by mate.

game 94, rofChade - Seer: Almost all pawns stayed on the board and the engines shuffled for a long time. Evals were close to 0 but there were too many pieces on the board for the draw rule, then Seer lost on time again.

game 96, Caissa - Clover: There were almost no exchanges after the start and the engines mostly shuffled for a long time. Evals increased a little after move 45, Caissa pushed pawns and restricted the black pieces further. Caissa created a passer after a piece exchange, after more shuffling there were some more exchanges and only RB vs RN remained. Caissa had unstoppable passers, Clover lost material and was mated.

game 103, Igel - Minic: Igel opened the king side, captured a pawn and created a passer. Minic exchanged pieces and regained the pawn, the game reached a RBN vs RBN position. The white king moved forward to support the passer, Igel captured a second pawn and Minic lost more material. The game ended in a tablebase win. 

game 107, rofChade - Clover: All the pawns were on the board, rofChade pushed its pawns and the black pieces had to retreat. Clover gave a bishop for two pawns, the engines exchanged pieces and pawns and the game reached a RN vs R position. Clover had two passers, onr was captured and the other blocked. eventually rofChade managed to exchange rooks, then queen a passer and mate.

game 109, DeepSjeng - Igel: DeepSjeng seemed to be in control in a RB vs RR position with two advanced passers on the 6th and 7th ranks. However it didn't find the best moves and Igel managed to hold.

game 121, rofChade - Igel: rofChade was up a pawn and evals slowly increased with no exchanges. The engines started exchanging pieces after move 33 and the game reached a QRR vs QRR position. The black king was in danger and Igel gave two pawns to get all pieces involved in the defense. rofChade exchanged a pair of rooks and pushed two passers forward, eventually Igel lost a rook to stop them, game over.

game 124, Clover - Revenge: Clover controlled the open d file, it captured a pawn and created a passer on the queen side. Revenge gave a bishop for two pawns to expose the white king, but it ran out of checks after a while. Clover reduced to a RN vs R position, the game ended in a tablebase win.

game 127, Igel - Seer: There were no exchanges after the start, the first pawns were exchanged on move 20, the piece exchanged on move 29. Seer had a trapped bishop and evals increased steadily. Igel went two pawns up and reduced to a RB vs RB position, then it captured the trapped bishop. Igel queened a passer and mated.

game 129, Minic - Clover: The engines opened files in the center and evals increased. Clover gave a rook for a bishop, the white king was exposed but after Minic exchanged queens its king was safe. The engines reduced to a RN vs BN position, Minic captured more pawns and the game ended in mate.

Standings after RR2: RubiChess +8, rofChade +6, Igel +5, Caissa +3, Clover +2, Minic +1, Seer Revenge 0, Viridithas -3, Fritz -6, ScorpioNN -7, DeepSjeng -9. RubiChess leads at the half way point, it lost its first game and drew two games with opening advantage. rofChade is in 2nd with Igel close behind, rofChade beat Igel in their direct game pair which could be important in a tiebreak situation. Caissa and Clover both improved their rank, they still have a small chance of advancing for the 3rd time this season. Seer crashed 3 times on time, it was losing against Caissa but it gifted wins in drawn positions to Clover and rofChade. I hope the qualification spots will not be decided by these crashes.

game 136, Minic - Caissa: Minic was a pawn up, the engines exchanged minors and reached a QRR vs QRR position. Minic kept its queen and exchanged rooks, in a queen ending the engines traded pawns. Minic managed to capture all the black pawns and kept two to win.

game 137, RubiChess - Clover: RubiChess was a pawn up, the engines cleared the queen side and RubiChess had a passer there. The engines gradually exchanged pieces and the game reached a B vs N ending. RubiChess pushed the passer to the 6th rank, then moved its king forward. Clover couldn't block the passer and keep the white king away, it lost its knight and the game.

game 143, rofChade - Revenge: rofChade was a pawn up, it created a passer in the center. rofChade gave a bishop and attacked through the center, Revenge gave back a knight to keep its king safe. More pieces were exchanged, Revenge captured the passer but rofChade captured pawns and the game reached a rook ending with enough advantage to win.

game 145, Fritz - Igel: Fritz had a passer on the 6th rank but wasn'r strong enough to push it forward, Igel's eval dropped to 0. When Fritz pushed another pawn Igel saw an opening to attack the exposed white king. It gave a pawn and risked facing 3 connected passers, Fritz realized its mistake too late. Igel used checks to capture the white passers and reduce to a RB vs RN position 2 pawns up. This was enough to later queen a passer and win.

game 151, Igel - Clover: The engines exchanged a few minor pieces, most pawns remained on the board. After some shuffling the engines opened files on the queen side. Igel threatened pieces with pins and forks in the center, the tension was released in a series of exchanges that left a RN vs BN position. Igel captured two pawns to win.

game 160, Seer - rofChade: The black king moved without castling, and the king side rook could only develop through the h file. Seer captured a pawn and created an advanced passer in the center. rofChade shuffled while Seer walked its king to the queen side, then a series of exchanges reduced to a RBN vs RBB position with white two pawns up. rofChade captured the passer but Seer captured all remaining black pawns and was 5 pawns up, it pushed its pawns forward to win.

game 164, DeepSjeng - Clover: There were almost no exchanges after the start, a pawn exchange opened the g file. DeepSjeng castled long and moved its pieces to the king side, then switched to the queen side when both engines created passers there. DeepSjeng captured a rook for a knight and hid its king behind a black passer. The engines exchanged queens after the black king was threatened, then DeepSjeng captured a rook for its passer, followed by mate.

game 168, Revenge - Minic: Revenge pushed a pawn to h6 and castled long. The black queen moved forward and captured two pawns but the black king was stuck in the center surrounded by open files. Revenge gave a rook and attacked with all its pieces, Minic couldn't find a safe spot for its king and it lost the queen by a fork. The game reached a QBN vs RRB position, Revenge continued to chase the black king and forced mate.

game 176, rofChade - Caissa: A series of exchanged left a QR vs QR position. rofChade had an advanced passer in the center that Caissa blocked. It took rofChade 25 moves to push the passer to the 7th rank and 10 more moves to reduce to a king and pawns ending. Caissa captured the passer, material was equal but the white king was better placed to ensure the win.

game 181, RubiChess - Igel: After the start RubiChess had a bishop pair advantage and an advanced passer in the center. In a QRB vs QRN position RubiChess pushed the passer to the 7th rank and Igel couldn't get rid of it. The engines exchanged queens, RubiChess created a second passer, Igel captured one but the other promoted to a queen. RubiChess lost the rook but had enough material to win.

game 189, Fritz - Caissa: The black king moved without castling, trapping the king side rook. The engines gradually exchanged pieces until only RBN vs RBN were left, Fritz went a pawn up and created two passers. After exchanging bishops Caissa captured one passer, it lost the knight for the other. It took Fritz another 17 moves to reach a tablebase win.

game 190, Revenge - Clover: There were many exchanges after the start and the game reached a QRN vs QRN position. Clover had two isolated pawns, after exchanging queens Revenge captured one. Revenge had a rook on the 7th rank, the white king moved forward, Clover lost material and was mated.

game 196, Caissa - Revenge: The engines opened the king side, Revenge gave a knight for a pawn to gain a development advantage. However, Caissa managed to develop its pieces and in a series of exchanges reduced to a RBN vs RB position. Revenge pushed a passer forward and Caissa gave a bishop to stop it, by then Caissa was two pawns up. The white king moved forward and captured the last black pawn, the game ended in a tablebase win. 

Standings after RR3: RubiChess +14, rofChade +9, Igel +8, Caissa +4, Revenge Seer +1, Clover -1, Minic -2, Viridithas -5, Fritz -8, ScorpioNN -9, DeepSjeng -12. RubiChess increased the lead after another RR with 6 white wins and no loss. rofChade has an advantage in the race for 2nd place over Igel, though anything can happen. Caissa is probably too far behind to have a chance to advance. Clover dropped after a poor RR with 4 losses and one win. Seer climbed a little, it had no crashes in the RR.

game 207, RubiChess - Caissa: The center was blocked and the c file was open, there were only a few exchanges after the start. Caissa walked its king to the queen side, it was without pawn support but not under attack. The game reached a RNN vs RNN position, after move 40 evals slowly increased. RubiChess captured a pawn, aftr exchanging a pair of knights RubiChess created 2 connected passers. Caissa regained the pawn and captured one of the passers, rooks were exchanged leaving a knight ending. The white king was much closer to the pawns, RubiChess captured the remaining black pawns to win.

game 209, Revenge - rofChade: Revenge was a pawn up, the engines opened the king side, rofChade castled long but Revenge castled short. rofChade tried to attack the white king, but was not strong enough after exchanging queens. Revenge captured another pawn and lost a knight temporarily, a series of exchanges reduced to a RBN vs RBN position with white a pawn up. Revenge had a passer, it avoided exchanging rooks until it captured another pawn. The white king came forward and Revenge captured the last black pawn. The game ended in a tablebase win.

game 218, Viridithas - Caissa: Viridithas pushed pawns and opened the king side. The white king walked to the queen side without castling, Viridithas doubled its rooks on the h file. The game reached a QRR vs QRR position and Viridithas attacked the back rank. Caissa tried to protect its king, it lost first one pawns then another and Viridithas reduced to a winning king and pawns ending.

game 223, Igel - Revenge: Most of the action after the start was on the queen side, both engines created a passer there. Igel gave two pawns, letting Revenge have 3 passers but exposing the black king to attack. Igel captured pawns and the game reached a RRB vs RRN position with white a pawn up. Revenge lost a piece for a white passer, Igel had enough advantage that it gave its bishop to reduce to a winning 7-man rook ending. It took another 35 moves to adjudicate the game.

game 231, Viridithas - rofChade: Both engines didn't castle their king, there were only a few exchanges after the start and the engines mostly played behind their pawn lines. After opening the king side and exchanging a pair of rooks Viridithas gave 2 pawns and captured a bishop. In a RBN vs RN position Viridithas captured 3 pawns and pushed passers forward. rofChade couldn't avoid a queening, game over.

Standings with 5 round to go: RubiChess +16, Igel +11, rofChade +9, Seer +4, Caissa +3, Revenge +1, Clover 0, Minic -1, Viridithas -4, Fritz ScorpioNN -12, DeepSjeng -15. Drama in the fight for 2nd place. Igel won 3 games in white against lower ranked engines, and rofChade lost twice in black. Igel is leading rofChade by a point with 5 games to play, it still has to play black against rofChade and rofChade has a tiebreak advantage.

game 235, Igel - Minic: Minic was a pawn up and Igel had a bishop pair advantage. The engines cleared the queen side pawns and shuffled for a while, evals were mostly stable until move 45. Igel regained the pawn and reduced to a RBB vs RBN position. Minic may have held longer but it was inaccurate in time pressure, Igel threatened mate and Minic had to give a rook for a bishop. The game ended in a tablebase win.

game 247, Igel - RubiChess: RubiChess pushed the g pawn and Igel moved a bishop to h6, disrupting the black king's castling. The engines opened the king side, RubiChess captured two pawns and the white king was exposed. RubiChess gave a rook for a bishop and blocked the g file, then it castled long and the game reached a QRR vs QRN position. Igel moved its pieces forward, RubiChess delayed with checks but eventually Igel reduced to a R vs N ending. Igel captured pawns, then queened a passer and mated.

game 250, Fritz - Clover: Fritz was a pawn up with eval advantage but Clover seemed to equalize. Clover gave a bishop for two pawns and exposed the white king. On move 42 Fritz blundered twice, it saw Clover's response in its PV but realized the mistake only after Clover moved. Clover used an attack on the white king to capture the white queen and reduce to a QN vs RRB position with black two pawns up. Fritz couldn't defend against the rushing passers and the attacks on its king, it lost pieces and the game ended in a tablebase win.

Standings with 2 rounds to go: RubiChess +16, Igel +13, rofChade +10, Seer +4, Caissa Clover +2, Revenge +1, Minic Viridithas -3, ScorpioNN -12, Fritz -14, DeepSjeng -16. Igel increased the gap to rofChade to 1.5 points. rofChade only drew as white against Clover while Igel beat RubiChess as white. With two games to play this is a substantial advantage for Igel, though it still has to face rofChade as black.

game 253, rofChade - Igel: rofChade castled long and pushed pawns on the king side, placing a pawn on h6. Evals started to increase after the center was opened, Igel pushed pawns on the queen side, rofChade went a pawn up and created connected passers. rofChade gave back the pawn to bring a passer to the 7th rank. In a RB vs RB position rofChade pushed a second pawn forward, Igel lost material and was mated.

With this win rofChade is only 0.5 points behind Igel in 2nd place. In the last round rofChade plays as black and Igel as white so Igel still has an advantage. In case of a tie rofChade will advance.

The Igel - Seer game 259 didn't start properly and had to be restarted. As a result the game was played last, after the ScorpioNN -  rofChade which was supposed to be last according to the schedule.

rofChade held a draw against ScorpioNN as black. Igel needs a draw to finish in 2nd place.

game 259, Igel - Seer: Igel captured the h pawn and exposed the black king to attack. The white d pawn became a passer, the game reached a QRN vs QRN position. After exchanging queens Igel captured all the black pawns and was 5 pawns up. Seer tried to avoid a 7-man tablebase loss but it couldn't avoid a queening and mate.

Igel secures 2nd place with this win, rofChade finished 3rd.