Arasan @ WCRCC tournament
Posted: Mon Jul 23, 2007 4:02 pm
A few notes from Arasan's games at the recent ACCA WCRCC tourney:
IkarusX played a strong game against Arasan in round 2. Arasan's
score just went straight down - no obvious blunder but it was
outplayed.
In round 3, Arasan played Clarabit, came out of book on move 12, and
then apparently couldn't find anything better than a draw by
repetition. So the game was drawn on move 15. Generally the book is
pruned to eliminate quick draw lines but this one was still
there. Still, Arasan should have avoided this by search if possible:
it generally will not take a draw against a lower-rated opponent.
Could be a bug, although in the next game it correctly declined
several draw offers from Tinker.
In round 4, Arasan had Tinker as an opponent. Arasan crashed on move
15, and when I re-started and re-connected, it crashed again in the
same position. This is peculiar because I've run it for days
(literally) without problems - I guess it is the "tournament effect,"
where bugs show up when least welcome. I restarted it the 3rd time
running with 1 CPU and left it in that mode until round 8. I didn't
see any more problems. I also can't reproduce this crash by reloading
the game and starting it to search at move 15, so it is probably some
obscure bug that depends on prior search status, like hash table
contents. It ran fine with 2 cpus from round 8 on.
Against Quark in round 5, Arasan built up an impressive-looking attack
but it petered out. In the endgame it was even but Arasan blundered
here:
[D] 2R5/8/8/2Bp4/1Pk1p3/5pPK/1r6/8 w - -
by playing Kg4. I think it could have held, despite Black's
impressive-looking pawn chain. I can't make it play Kg4 offline, so
this is another item to investigate.
Arasan lost in round 7 against LearningLemming - a bit disappointing
since Arasan has a + score against this program on ICC. Arasan
came out with a - score from the opening and never got better.
I am not clear where it went wrong but after 31. Rc5 (which it
did not expect), its score dropped decisively.
Round 8 was a nice win against DirtyX. Arasan was in book until move
20 and DirtyX went wrong very soon afterwards and was smashed by
a strong attack.
The game against Weid in round 10 was interesting. Arasan got an
advantage out of the opening and was up over +1 at one point. But its
advantage dwindled. Finally it lost in the endgame.
This is the position at move 64:
[D] 5r2/5B2/3p1n2/B1pP4/P1N1pp1P/5k2/2K5/8 w - -
Arasan still showed a small + score here, but the key issue is that
the White King really can't go anywhere, while Black's king is mobile
and is next to the connected passers. White's 2 pieces for the Rook
and two passers don't count for anything. A couple moves later,
Arasan's score dropped and it lost. I don't see a blunder here, but it
mis-evaluated the position and should have avoided this endgame if
possible. Weid's score went up several moves before Arasan saw any
danger.
Overall Arasan wound up in 11th place which is about where you'd
expect based on its initial seeding.
--Jon
IkarusX played a strong game against Arasan in round 2. Arasan's
score just went straight down - no obvious blunder but it was
outplayed.
In round 3, Arasan played Clarabit, came out of book on move 12, and
then apparently couldn't find anything better than a draw by
repetition. So the game was drawn on move 15. Generally the book is
pruned to eliminate quick draw lines but this one was still
there. Still, Arasan should have avoided this by search if possible:
it generally will not take a draw against a lower-rated opponent.
Could be a bug, although in the next game it correctly declined
several draw offers from Tinker.
In round 4, Arasan had Tinker as an opponent. Arasan crashed on move
15, and when I re-started and re-connected, it crashed again in the
same position. This is peculiar because I've run it for days
(literally) without problems - I guess it is the "tournament effect,"
where bugs show up when least welcome. I restarted it the 3rd time
running with 1 CPU and left it in that mode until round 8. I didn't
see any more problems. I also can't reproduce this crash by reloading
the game and starting it to search at move 15, so it is probably some
obscure bug that depends on prior search status, like hash table
contents. It ran fine with 2 cpus from round 8 on.
Against Quark in round 5, Arasan built up an impressive-looking attack
but it petered out. In the endgame it was even but Arasan blundered
here:
[D] 2R5/8/8/2Bp4/1Pk1p3/5pPK/1r6/8 w - -
by playing Kg4. I think it could have held, despite Black's
impressive-looking pawn chain. I can't make it play Kg4 offline, so
this is another item to investigate.
Arasan lost in round 7 against LearningLemming - a bit disappointing
since Arasan has a + score against this program on ICC. Arasan
came out with a - score from the opening and never got better.
I am not clear where it went wrong but after 31. Rc5 (which it
did not expect), its score dropped decisively.
Round 8 was a nice win against DirtyX. Arasan was in book until move
20 and DirtyX went wrong very soon afterwards and was smashed by
a strong attack.
The game against Weid in round 10 was interesting. Arasan got an
advantage out of the opening and was up over +1 at one point. But its
advantage dwindled. Finally it lost in the endgame.
This is the position at move 64:
[D] 5r2/5B2/3p1n2/B1pP4/P1N1pp1P/5k2/2K5/8 w - -
Arasan still showed a small + score here, but the key issue is that
the White King really can't go anywhere, while Black's king is mobile
and is next to the connected passers. White's 2 pieces for the Rook
and two passers don't count for anything. A couple moves later,
Arasan's score dropped and it lost. I don't see a blunder here, but it
mis-evaluated the position and should have avoided this endgame if
possible. Weid's score went up several moves before Arasan saw any
danger.
Overall Arasan wound up in 11th place which is about where you'd
expect based on its initial seeding.
--Jon
