Season 9, stage 1b, rounds 4-9 overview

There have been so many games on TCEC while I was away, and I have no way of going over all of them while the tournament continues. I'll just have a quick look at the results and write about things that look interesting.

Gaviota managed to draw Naum in the longest game of stage 1b (so far). Gaviota had an eval advantage but this only reflected a space advantage in a blocked position. The engines avoided the 50 moves draw several times, dragging the game for a long time.

Andscacs beat Chiron in another long blockade game. Andscacs found a way to get a decisive advantage, though parts of the game seemed like random shuffles. A win against one of the stronger engines of the stage shows that Andscacs is contender for qualification.

Arasan was able to hold Andscacs to a draw, and then it crashed. What a missed opportunity.

Stockfish beat Naum with black pieces. All the pieces were concentrated on the king side, and Stockfish's pawns limited Naum's movement until it was ready for the killing blows. This was the first strong engine Stockfish beat this season.

Jonny - Fire ended in a draw. Jonny is doing well so far in this stage, better than I expected.

Stockfish - Nirvana was a 21 move miniature that ended in a 3-fold repetition. Nirvana is also doing very well so far, and Stockfish is not dominating the field.

Andscacs couldn't get more than a draw against Fruit, a little disappointing for the ambitious newcomer.

After 6 rounds the top of the table was:
Nirvana 5
Jonny, Stockfish, Andscacs 4.5
Naum, Chiron, Fire, Critter 4
Vajolet2 3.5

Chiron lost to Jonny after it went for an early pawn sacrifice which did not work. Another important win for Jonny in the qualification race.

Naum beat Andscacs in a long and technical RB vs RB endgame, using an advanced passed pawn on the queen side to win pawns on the king side. An important result for both engines in the qualification race.

Nirvana beat Critter in a rook ending. Critter playing with tablebases seemed to blunder a drawn ending, and Nirvana playing without tablebases saw the win 10 moves before Critter did. Critter will have to work hard to qualify, while Nirvana's performance is excellent.

Gaviota was a pawn down against Fire, but managed to hold a pawn line, filling the gap with rooks. When Fire broke through to avoid the 50 move draw Gaviota was able to draw with perpetual checks. Respectable result for Gaviota, Fire still in danger considering it also crashed earlier.

Andscacs had an eval advantage over Nirvana but it never seemed that Nirvana was in any danger and the game ended in a draw. Another solid result for both engines.

Vajolet2 could only get a draw against Fruit. Vajolet's qualification chances are declining.

Arasan - Jonny reached a RN vs RB endgame on move 16, Jonny sacrificed pawns to get a dangerous passer but Arasan got the draw through perpetual check. Arasan won't qualify but it can still be a tough opponent.

Naum - Vajolet2 was a long and complicated game. In the bishop ending Vajolet2 kept seeing a Naum win while Naum was shuffling without an idea of how to proceed. Ironically it was Vajolet2 that moved a pawn, resetting the 50-move counter and letting Naum see the path to victory.

I would have thought that the Fire - Stockfish game would be the fight for first place of stage 1b, but that is not the case. In the game Stockfish never had an advantage but it also never gave Fire anything to work with. Fire thought it had something near the end but it was just an illusion, the game ended in a draw.

After 9 rounds the top of the table was:
Nirvana 7.5
Jonny, Stockfish, Naum 7
Andscacs, Chiron, Fire, Critter 6
Vajolet2 5