Saturday, May 21, 2016

Season 9 stage1a, rounds 13-15

Final standings,stage 1a:

Qualifiers are: Komodo, Houdini, Rybka, Protector, Gull, Ginkgo, Hannibal, Raptor. The race for 8th place was close and was only decided in the last game of the stage.

The final draw rate for stage 1a is 34/120 (28%).

Some of the game highlights: 

Ginkgo-Rybka was down to RRBB vs RRNN very early. Rybka had a pawn advantage, and with 13 pawns on the board Ginkgo's bishop pair wasn't very strong. The game was not static with many pawn advances and exchanges, and neither side could get an advantage. After more than 30 moves the first piece was exchangedLater when the first rook pair was exchanged both engines lowered their evals and a draw was adjudicated.

Gull-Hannibal was a long game, important for Hannibal's chances of qualifying. Gull thought it had a small advantage in a RRBB vs RRBN position, with all pieces behind pawn lines. The position opened up 40 moves later, with no eval improvement, reduced to a RB vs RB with opposite color bishops and very few pawns. When it was down to one last white pawn the draw was certain, since black could sacrifice a bishop and get a tablebase position RB vs R. Gull wouldn't stop for another 70 moves though...

Fizbo lost to Protector, making the game against Hannibal its last chance of qualifying (I doubt Hannibal will lose against Fridolin, and Fizbo has Rybka left).

In the battle for last place, Fridolin reached a drawn rook ending against Myrrdin, and then instead of getting its first (and only) score Fridolin lost on time!! What a tragedy...

Hakkapeliitta managed to hold off Komodo for over 45 moves, but as usual Komodo found the win in the endgame. Another respectful performance by Hakka (with one cpu).

Bobcat played well against Raptor. Starting from a small advantage in the opening Bobcat reached a RRBB vs RRNN position. Its pieces were more active than Raptor's and it was able to get a decisive two pawn advantage in a double rook ending. This was a bit of a surprise for Raptor, hurting its qualification chances.

Raptor's next opponent was Houdini. Raptor was dreaming it was ahead when Houdini sacrificed a knight for 3 pawns, but it was not a match to Houdini's endgame abilities. When the game reached a RRBN vs RRB position Houdini was firmly in the lead. After an exchange of a rook for a knight and two more pawns Raptor couldn't stop the advancing pawns even with an extra rook. Another blow for Raptor, two losses in a row.

Hannibal-Fizbo was crucial for the qualification chances of both engines. It started with a small advantage for white, and very quickly Hannibal was able to put a lot of pressure on the black king. As a result Fizbo gave a rook for a knight, leading to a RR vs RB endgame. This time Hannibal was able to convert the win, even without tablebase support. This secured Hannibal's qualification, Fizbo's probability to advance became very low.

Rybka-Gull was a bit of a surprise since Gull lost quite easily. It made some bad choices in the opening, leading to a position with an uncastled king and a pawn down. This was a big enough advantage for Rybka to win, even if it took a long time to finish. Considering Gull's record from season 8 it is a bit surprising that it lost to Rybka and Houdini in season 9. All three engines have not changed for a while, is it the hardware? Just plain bad luck?

Last round: Raptor, Fizbo and Texel on 6.5 points, Bobcat with 6, are still in the race for the last qualifying place. Bobcat will surely win against Myrrdin, and it has a better SB score than the rest. Can one of the other contestants win the last game? My bet is on Raptor against DisasterArea, the last game of the stage.

Texel lost to Gull, and won't qualify.Texel had some hope of a draw while the position was closed, but Gull's eval jumped when it sacrificed a knight and attacked the black king. Texel had to lose material to get out of trouble, and the endgame of RRB vs RNN was not easy, but Gull managed to get the win.

Fizbo-Rybka started with a small eval advantage for white, but Rybka turned the game around and was a pawn up. WIth very few pieces remaining Fizbo was able to equalize and reach a 6-man drawn position, and then Fizbo crashed. Not again!! The engines seem to be losing their mind these last rounds. A draw would probably not be enough to qualify, but now Fizbo is also out.

In the Hakkapeliitta-Protector both engines thought white had a significant advantage when a RRB vs RRB ending was reached on move 28, with Hakka a passed pawn up. The evals dropped after the rooks were exchanged, leading to a opposite color bishop ending, where one pawn is usually not enough. Did Hakka blunder the endgame?

In the last game of the stage Raptor beat DisasterArea in black to qualify for stage 2. The game reached a RRB vs RRN ending after 25 moves. Raptor's pawn attack on the king side trapped DA's king and allowed Raptor to create a passed pawn on the queen side. DA was forced to lose a bishop to avoid queening, losing the game.

Featured game: Houdini - Komodo
Stage 1a, round 15
Link to game on TCEC

This was the game that decided who will finish first in stage 1a. Komodo was 0.5 points ahead so Houdini needed a win. Komodo is usually stronger but in one game anything can happen.

In the first 20 moves the game was very balanced with evals close to 0. The game seemed to be heading for a draw, but Komodo's evals were slightly in its favor. Houdini's pieces were a bit cramped on the back row, but could Komodo find a crack in the position?

There followed a few inaccuracies by Houdini, at least considering what Komodo recommended as well as the resulting position. Komodo was able to concentrate all its firepower on the king side with open files ready to attack. Houdini's defense was looking shaky and vulnerable.

Houdini tried to defend as best it could, but in the aftermath of the attack Komodo was a pawn up, still threatening the white king and with too many pawns that had to be blocked.

Houdini continued to lose material and the game ended a few moves later. Komodo is the unbeaten champion of stage 1a !!!

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