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Subject: Arasan in CCT8

Author: Jon Dart

Date: 19:12:51 02/26/06


A few notes from Arasan's games in CCT8:

Arasan is playing on faster hardware this year and
also has gotten a significant speed boost (20% or so)
from being built with Visual C++ and Profile-Guided
Optimization (PGO). I tried the Intel compiler with
PGO, but did not get as good results.

It has also had quite a bit of eval tuning in the
last year and now is using history pruning, besides
all the other pruning tweaks version 8.4 has.

The first game was against "Crash Test Dummy", ctd,
which Arasan won decisively. ctd has no opening book but
played quite a reasonable opening. However, it allowed
too many pawn weaknesses. 24. b4 starts an attack that
opens up the position, gains material and leads to a
passed pawn that can't be stopped

Arasan was smashed by Ikarus in round 2. Ikarus played
1. g3 and Arasan was out of book fairly quickly. Arasan
had a + score through most of the opening, but 31.
bxc5 was unexpected and after that it was in negative
scores. Ikarus pushed two pawns to the 6th, cutting off
the Black bishop and posing threats. The end was ugly
as Arasan tried to throw away material to stave off mate.

witchess had Black against Arasan and played a weird kind
of Nimzo/QGA hybrid (it is another program without a book).
The game looked ok when I stepped out to run an errand, but
when I came back Arasan had lost. 33.. Rxa3 was surprising -
Arasan did not expect this, but also didn't see any big
problem from it. 57 .. f4+ was another unexpected blow, much
more decisive. Good game from witchess.

I was still gone and didn't watch the game against
Chompster. Chompster played 1. d4 Nf6 2. f3, which put
Arasan out of book right away. Then it followed up with 4.
g4 and 5. g5, which might make Grob fans happy, but can't be
good. After 25.  Rxf7 Qxf7 26. Rxf7, Black has two Rooks for
the Queen, which Arasan was happy to take. Arasan ate some
pawns and eventually pieces, to finish up with a big
material plus.

Next round, jsbam played some strange Gruenfeld variation
and was in trouble right away (Arasan's score on move 7 was
0.5 out of book). Arasan won easily.

Next game was Crafty. I remarked online that Arasan
has beaten Crafty in casual ICC games, but has never scored
against it in a computer chess tournament. I know Bob has
been tweaking the eval recently and that has probably led to
some decrease in playing strength. Crafty is still
incredibly fast - it was searching 4 million NPS or so (vs.
1-1.5M for me). But Arasan was getting more depth in some
cases (may not mean much because Arasan is fairly selective
and you can miss a lot that way).

Arasan played the Meran variation and was in book until move
23. The Meran is full of opportunities for both sides
to go wrong, but against a properly booked opponent
it seems to be drawish (in my experience) and that
proved to be the case here. I had a little scare when
Crafty's eval went briefly above +1, but basically it
was a boring endgame, ending with draw by repetition.

The next game was against Quark, which is a pretty strong
program. Arasan got an advantage soon out of the opening
(Ruy Lopez). 19. Nf5 looks strong and Quark failed low
at this point. At move 23, Arasan expected .. a5, but
Quark played .. Re6, and in the following tactics, Quark
lost a Rook for a Bishop. Arasan simplified down, but
in the end it had a rook file passer vs. Quark's one on
the c file. Quark was able to block the pawn and draw by
repetition.

The 8th round Arasan was Black against Hossa. Hossa has
been challenging competition in the past, but now I think
Arasan is stronger. The opening was a fairly even English
Opening. I don't think Arasan would play 18. f4, which
opens up the King side. Also 28. b4 and 29. bxc5 open up
the b file, which Arasan winds up occupying. Arasan's
35 .. Rdb8 doubled Rooks on the b file and led to a
massive advantage.

Against Glaurung, Arasan played a QGD Tarkatower.
I was not very happy to see this opening since Arasan
doesn't have a particularly good track record against
it. Arasan was out of book on move 10 (older versions
have 10 .. c5 as a book move but the current version
doesn't). I am not quite sure where Glaurung went wrong.
The culmination of a lot of piece manouvering and some
exchanges was that Arasan had an outside passer on the
b file, and this proved to be decisive.

Overall I was glad to score 6/9, which is a personal best
for Arasan in CCT.

I greatly appreciate Peter's organizing and directing
this.


--Jon




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