Monday, April 8, 2019

Season 15 division 1 results

Final crosstable

KomodoMCTS and AllieStein promote to the premier division. KomodoMCTS will try to stay in the premier division, it seems to have solved the stabilllity problems that caused it to drop to division 1 last season. AllieStein started this season in division 4 and climbed all the way to the top. It is the second NN engine in the premier division after Leela.

Jonny and Chiron are relegated to division 2. Of the 4 engines that stayed in division 1 last season only Laser seems to be improving and strong enough to face the newcomers. Chiron still has stability problems, Fizbo and Jonny fought each other and in the end Fizbo survived.

The race for the top 2 places was close for a while. AllieStein had a weaker second half with only 2 wins and one loss, while Xiphos and Laser were not too far behind. In the end AllieStein held 2nd place comfortaby enough. Andscacs started weak but ended the division stronger, including two quality wins against AllieStein and Laser. The race against relegation was close. Jonny beat Fizbo in RR4 and closed the gap. A second win put Jonny ahead of Fizbo, but in the last round Jonny lost and the scores were tied in the end. Fizbo survived on a tiebreak, it had more wins than Jonny.

The engines that will play in the premier division: Stockfish, Leela, Komodo, Houdini, Fire, Ethereal, KomodoMCTS, AllieStein. The engines will play 3 DRRs with time control of 90+5.

A few interesting games

Chiron - Laser: The game reached a BN vs BN position on move 30. Evals were negative and they increased very slowly as Laser outplayed Chiron in a long endgame. After exchanging a bishop for a knight Laser's remaining knight was much stronger than the white bishop. Chiron had to defend its weak pawns and eventually couldn't stop the black king penetrating the queen side and winning the game.

Xiphos - Fizbo: There were many early exchanges, only RB vs NN remained on move 27 with Fizbo two pawns up. Xiphos opened a file on the king side and moved the rook behind the black pawns. Fizbo couldn't prevent the creation of a king side passer that won the game for Xiphos.

KomodoMCTS - AllieStein: A 20 move miniature that ended in a repetition draw.

Chiron - Xiphos: Xiphos gave a knight for pawns and forced the white king to move uncastled early in the game. Xiphos had a queen side passer and Chiron's king side rook was trapped in the corner. Chiron lost a piece when it tried to free its rook. The game reached a rook ending with Xiphos 3 pawns up, a straightforward win.

KomodoMCTS - Fizbo: Fizbo gave a pawn at the start, evals increased very slowly as the engines exchanged pieces. On move 46 only QNN vs QBN were left and evals were over 1.5. Ten moves later the engines reduced to a N vs B ending. KomodoMCTS used the extra pawn to create a queen side passer. Fizbo lost the bishop to stop the passer and the game was over.

Chiron - KomodoMCTS: The game reached a RR vs RNN position on move 25 with Chiron 2 pawns up and evals close to 0. There were many pawns on the board and the black knights were more effective than the rooks. KomodoMCTS outplayed Chiron, it captured a pawn and created a pawn majority on the king side. The threat of a passer was enough to force Chiron to give a rook for a knight and the game was adjudicated.

Jonny - Xiphos: Jonny was a pawn up with two connected passers on the queen side, yet evals turned negative due to Xiphos controlling the light squares and a hole in the white king's defense. Xiphos' eval jumped when it pushed pawns on the king side. Jonny exchanged pieces and gave a bishop but couldn't get out of trouble, the game was adjudicated before Xiphos won more material.

AllieStein - Xiphos: The engines castled in opposite directions, AllieStein pushed a pawn to h6 and its eval started to increase. The game reached a QRB vs QRN position on move 22, AllieStein's eval jumped over 2 after it created a queen side passer. After exchanging queens AllieStein pushed the passer to a6, Xiphos had to block it with its knight. Eventually the white king penetrated the king side and captured two pawns, winning the game.

Andscacs - Jonny: The game reached a QR vs QB position on move 26. Jonny protected its center pawns with the bishop, but its defense crumbled after Andscacs opened the king side. After exchanging queens Jonny couldn't stop the white pawns on both sides.

KomodoMCTS - Laser: Evals were low for the first 50 moves, the position was closed except for a file on the queen side that KomodoMCTS controlled with its rooks. Laser exchanged bishops and allowed KomodoMCTS to take over the back rank in a QRR vs QRR position, evals started to jump quickly. The engines reduced to a queen ending, KomodoMCTS was a pawn up and that was enough for a win.

Fizbo - Chiron: Chiron captured a rook for a bishop and Fizbo's eval jumped over 1. Chiron had a rook and bishop trapped on the queen side, the white pieces were very active and they had many targets. Fizbo managed to get the material back and after several exchanges the game reached a QN vs RRB position. By the time Chiron freed its trapped rook Fizbo gained more material, it was a pawn up in a Q vs RB won ending.

Chiron - AllieStein: The network crashed, the game was later resumed and ended in a draw.

Laser - Fizbo: Laser had an eval advantage under 1 from the start. It pushed a pawn on the king side and punched a hole in the black king's defense. The engines exchanged down to a QRR vs QRR position and the black king walked to the queen side. Evals started to jump after Laser opened the queen side, it went a pawn up and exposed the black king and the game was adjudicated.

Xiphos - Andscacs: The center was locked and Xiphos attacked the queen side. It went a pawn up and created a passer in the center. The passer reached the 7th rank and evals were over 4. Andscacs captured the passer but lost a piece, the game was adjudicated soon after that in a QRB vs QR position.

After RR3: KomodoMCTS +6, AllieStein +5, Xiphos and Laser +2, Andscacs +0, Fizbo -2, Jonny -5, Chiron -8. Both the top 2 and the bottom 2 have a gap of 1.5 points to the closest engine. There are 7 games per engine left to play.

AllieStein - Andscacs: See featured game below. This was AllieStein's first loss in the division.

Jonny - Fizbo: Jonny was a pawn up, the game reached a QRR vs QRR position with two passers each for both engines. Fizbo pushed a passer to the 2nd rank, then pushed the second and Jonny's eval jumped over 5. The black king was exposed to attack while black passers shielded the white king. Jonny chased the black king, capturing pawns in the process. The result was a double rook ending with Jonny two pawns up and a win. Jonny's first win in the division.

Laser - Chiron: The engines exchanged pieces until only BN vs BN were left on move 29. Laser captured a pawn and exchanged a knight for a bishop, evals increased over 2.5. Then Laser captured a second pawn and created connected passers on the queen side, enough for a win. Two wins for Laser in this opening.

Five rounds to go: KomodoMCTS +6, AllieStein +4, Laser +3, Xiphos +2, Andscacs +1, Fizbo -3, Jonny -4, Chiron -9. Two critical wins for Jonny and Laser, together with a loss for AllieStein, and the gaps at the top and bottom of the table are down to 0.5 points.

AllieStein - KomodoMCTS: AllieStein had an eval advantage from the start, it pushed pawns on the queen side and had more space. On move 26 AllieStein sacrificed a knight and its eval jumped over 2.5, KomodoMCTS saw the sacrifice coming but thought it could hold. Suddenly AllieStein had connected pawns in the center on ranks 6 and 7, KomodoMCTS saw the problem but too late. It gave material to stop the pawns and the game reached a RR vs RN position. The game went on for 30 more moves, eventually AllieStein went up 2 pawns and the game was adjudicated.

Xiphos - Chiron: Xiphos played better in a closed position, it patiently increased the pressure on the weak black pawns until Chiron's defense crumbled. Evals were over 4 when Xiphos captured a pawn, Chiron started to lose material and the game was over quickly. Xiphos won this opening from both sides.

Fizbo - KomodoMCTS: The engines castled in opposite directions, Fizbo pushed pawns on the king side but it did not have enough strength for an attack on the black king. Meanwhile KomodoMCTS' bishops both targeted the white king, and negative evals started to jump when the center opened. KomodoMCTS increased the pressure with its queen and rook on a open file, Fizbo could not defend and the game was adjudicated within a few moves. KomodoMCTS won this opening from both sides.

Three rounds to go: KomodoMCTS +6, AllieStein +5, Laser and Xiphos +3, Andscacs +1, Fizbo and Jonny -4, Chiron -10. Still nothing decided. AllieStein increased the gap to 1 point at the top. Fizbo and Jonny are tied, Fizbo has more wins and has a tiebreak advantage.

Andscacs - Laser: The game reached a RBN vs RBB position on move 32, Andscacs had an eval advantage under 1 with equal material. Laser exchanged pieces and reduced to a bishop ending, but it chose to take the wrong bishop and ended with same color bishops, evals jumped over 2.5. Laser couldn't defend its pawns and Andscacs created a passer to win.

Laser drops 1.5 points behind AllieStein and with 2 games to go it is almost surely out of the promotion race. Jonny and Fizbo are still tied.

Jonny - Andscacs: Jonny's eval was over 1 after it created a pawn majority on the queen side. Andscacs had a central passer and it felt relatively safe. Jonny pushed its pawns and its eval slowly increased, Andscacs miscalculated and thought it could counter with an attack on the white king and get a draw. It soon realized its mistake but Jonny was two pawns up in a won QR vs QR ending. Two white wins in this opening.

Xiphos drew its game against AllieStein and lost its chance to close the gap. It is 1 point behind, AllieStein has the head-to-head tiebreak advantage as well so Xiphos is out. Jonny's win puts it 0.5 points ahead of Fizbo before the last round. Fizbo has the tiebreak advantage (more wins), it needs to score better that Jonny in the last round.

KomodoMCTS - Jonny: The engines castled in opposite directions. Jonny pushed pawns on the queen side, it was not fast enough and KomodoMCTS took the initiative. KomodoMCTS pushed pawns on the king side and opened a file facing the black king. It increased the pressure and the evals increased , after a long series of exchanges KomodoMCTS won a piece and reduced to a winning BN vs B ending.

Jonny needed a draw to survive following Fizbo's draw against Laser. With this loss Jonny finishes 7th on a tiebreak and is relegated.

Featured game: AllieStein - Andscacs
Division 1, game 85
Link to game on TCEC

AllieStein had an eval advantage from the start. The engines castled in opposite directions, AllieStein pushed pawns on the king side while Andscacs opened a file on the queen side near the white king. Andscacs attacked with its queen and forced the white king to the center, both evals turned negative quite unexpectedly, AllieStein appears to have missed something.

Andscacs attacked through the center and opened files, while it gave a rook for a bishop. Evals were negative over 1.5, the engines exchanged down to a QRR vs QRN position with the white king completely exposed in the center and surrounded without the ability to move.

AllieStein had to give material to escape a mating net, the game reached a RR vs Q ending, Andscacs two pawns up. Evals were over 2 without change for a while. Could AllieStein hold this after all?

Andscacs chose to ignore its queen side pawns and it created a passer on the king side. AllieStein thought it had a chance when it captured both the black pawns on the queen side. This was a mistake and Andscacs' eval jumped over 7,  now AllieStein lost control of the black passer on the king side.

Andscacs pushed the h pawn and AllieStein could not stop it without losing a rook. The game was adjudicated with the passer about to promote.


  1. Dear Mr. Wool,

    Could you please upload or send me the .pgn files of TCEC Season 15? Regrettably, the games are not yet at their archive site. I have written to them but have not received any answer yet.


    Pablo Rodas Martini
    FIDE Master

  2. Pablo, try the archive of the updated website at
    All the pgns are there last time I checked.