Thursday, August 30, 2018

Season 13 division 1 after RR2

Crosstable after RR2

Chiron and Ethereal are tied at the top of the table, both seem to be on their way to qualify to the premier division. Fizbo in 3rd is the only engine without loss in the division, but it only has one win so far and it is two points behind the leaders.
The bottom of the table is more crowded. Jonny is last, it lost all its games against the leaders. Booot started the division with two crashes, but since it was limited to 16 threads it has been stable, drawing all its games except one loss. Laser, Fritz and ChessBrain are also very close to the relegation zone.

A few interesting games

Ethereal - Jonny: Ethereal had a strong knight pair which was better than Jonny's bishop pair in a closed position. Ethereal used the advantage to create a pair of connected passers in the center. Jonny's king was exposed in a QRN vs QRB position, Ethereal forced a queen exchange that led to a winning endgame.

Chiron - Fritz: Evals were close to 0 for the first 40 moves. The black king move forward on the king side where Chiron could attack it, This led to a simplification to a RB vs RN position with a pawn advantage for white. Chiron found a win after exchanging rooks.

Fizbo - Laser: Fizbo had an early pawn advantage on the queen side. Its eval was around 2 after clearing the center and exchanging pieces. After some shuffling the game reached a QRB vs QRN position. Laser was forced to give a rook for a bishop to remove one of the pawns and to avoid mate. The resulting endgame was winning for Fizbo.

Jonny - Chiron: Jonny played the opening badly and evals turned negative. Chiron opened files and pressed on the king side. Eventually Chiron managed to exchange pieces and reach a NN vs NN ending two pawns up. Two central passers were enough for a win.

ChessBrain - Ethereal: Ethereal started a king side attack with a knight sacrifice. After many exchanges and long forced lines only RR vs Q were left. Ethereal used its queen to attack the white king and capture pawns, ultimately winning though it took more than 25 moves.

Ethereal - Chiron: There were many early exchanges. Chiron went up a pawn and evals became negative, only RRN vs RRN were left on move 31. Chiron later gave the pawn back but gained two king side passers, Ethereal had to give a piece to stop them. The RN s R endgame was winning for Chiron. First loss for Ethereal in the season.

Fritz - Jonny: The game reached a RB vs BN closed position on move 64. Fritz broke through the queen side with a bishop sacrifice (after a Jonny blunder?). Jonny had to give its bishop to stop the passers and the R vs N endgame was a win for Fritz.

ChessBrain - Fritz: ChessBrain was a pawn down but up on eval. It blocked the center trapping the black rooks on the queen side, and attacked the king side. Fritz' king lost its supporting pawns and it was almost paralyzed. Fritz gave material to free itself, leading to a RN vs BB endgame,  ChessBrain two pawns up and winning.

Booot - Fizbo: After crashing twice Booot was reduced to 16 threads. Booot attacked on the king side, Fizbo defended and exchanged pieces. On move 31 RBN vs RRB remained, Booot two pawns up and with an advanced passer. It had a eval over 1.5 when it allowed Fizbo to trade pieces and pawns, leading to a draw.

Laser - Chiron: see featured game below. Chiron's first loss of the division.

Fritz - Ethereal: The center was blocked early in the game. Ethereal trapped the white king in the king side and then threatened to open the h file with a deadly attack. Fritz defended for a while but collapsed when Ethereal doubled rooks on the h file.

Jonny - ChessBrain: There were many early exchanges and only RRN vs RRN remained on move 21. Jonny's rooks controlled the central files, it had a pawn advantage on the king side with its king supporting the pawns. After exchanging a pair of rooks Jonny created a passer, and this led to a won rook ending. First win for Jonny in the division.

Jonny - Ethereal: Jonny grabbed a pawn and let Ethereal take the initiative and attack the exposed white king. An advanced black passer forced Jonny to trade its queen for RN, leading to a RBN vs QN position. Jonny was two pawns up but that was not enough against Ethereal's active queen. The game was adjudicated just as Ethereal was about to capture more white pawns leading to a clear win.

Chiron - Jonny: Jonny grabbed a pawn (again), allowing Chiron to trap its bishop. Chiron gave a second pawn to open the king side, and launched a strong attack. Jonny exchanged pieces to defend, this led to a QRR vs QRN position with Jonny two pawns up. However, the white rooks were strong with many open files and the black king was exposed, the game was soon adjudicated a win for Chiron.

Ethereal - ChessBrain: Ethereal was a pawn up early in the game. In a series of exchanges ChessBrain gave a rook for a knight and only QRR vs QRN remained, ChessBrain a pawn up. Ethereal traded down to a R vs N ending and an easy win.

ChessBrain - Chiron: The white king was too exposed, Chiron used a queen and bishop combination on the long diagonal to force the king back to the center. Then Chiron doubled rooks in an open file on the queen side and caught ChessBrain's queen in a pin. The game was adjudicated with Chiron a rook up.

ChessBrain - Laser: ChessBrain had an eval advantage of over 1 despite having a knight pair against Laser's bishop pair. The game reached a RN vs RB position, ChessBrain controlled the 7th rank and it slowly captured black pawns. When it was 3 pawns up ChessBrain exchanged rooks and the game was adjudicated.

Laser - Ethereal: Laser tried to weaken the black king side with a knight for pawn sacrifice, Ethereal turned this into a R vs NN imbalance with a growing eval advantage. Ethereal refused to exchange pieces, its eval jumping over 3 as it created an advanced passer in the center. Laser only had major pieces and could not afford to exchange with a black knight defender. The game was adjudicated when the passer reached the 2nd rank.

Booot - Chiron: Chiron opened the h file, and then very slowly it managed to move a rook and queen to the open file to threaten the white king. Chiron's attack pushed Booot's king to the center and after exchanging most pieces only R vs BN remained. Chiron played the endgame slowly, exchanging pawns until only one black pawn was left in a winning tablebase position. First Booot loss that was not a crash. 

Featured game: Laser - Chiron
Division 1, round 7
Link to game on TCEC

The opening looked drawish, evals were close to 0. Laser moved its knights to the king side and Chiron noticed the DS bishop was blocked and attacked it with a pawn. Laser sacrificed the bishop and opened the king side taking pawns with its knight.

Chiron thought its king was still safe. Chiron created a passer on the queen side, and Laser ignored it and continued to move pieces to the king side. When Chiron realized it was in trouble evals jumped over 2, despite having a passer on the 2nd rank.

Chiron lost its passer and Laser closed in on the black king, forcing Chiron to give its queen. Chiron countered with an attack on the white king, now Laser had to give its queen to escape. The game reached a RBN vs RRB position, Laser two pawns up and evals close to 4.

The black pawns were all on light squares, easy targets for the white bishop. Laser soon captured all the black pawns and was 4 pawns up, enough for a win.

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