TalkChess.com

[Jon Dart]

Arasan played in the recent ACCA Americas' Computer Chess tourney
(http://taccl.org/ACCAChampionships/ACCA2009Championships/2009AmericasChamp.html).

Arasan's first round game was against Tinker. Arasan and Tinker
have played over 700 games on ICC, with Arasan scoring quite a
bit better. Arasan played an English Opening and was in book
through move 17. It looks like this was the crucial point:

[D] 4r1k1/3qnppp/p7/1pR5/5P2/1Q1PpNP1/PB2PnKP/8 b - - 0 28

Here Tinker played 28. .. Qh3+, which certainly looks reasonable, but
after 29. Kg1 Qd7 30. Qc3!! Black is losing.

Against zct in round 2 Arasan played a French Defense. Arasan used
not to play the French at all but I've decided it's not all bad.
Arasan was in book through move 15. With 21. .. Rd2 Arasan posted
a Rook on the 7th and by move 35 it had two Rooks on the 7th - this
is a deadly combination. Arasan converted the following endgame to
a win.

Arasan-Amateur in round 3 was a main-line Nimzo-Indian. This looked
pretty even up until move 25:

[D] 3r2k1/p3qppp/8/nP1n4/4p3/P6P/2R1QPP1/2B2NK1 b - - 0 25

Here Amateur played .. f5?! and this allowed Arasan the nice forced
sequence 26. Ne3 Nxe3 27. Bxe3 Qxa3 28. Rc7! with a strong Rook
on the 7th rank. Another 8 moves and it was all over. Black might
have improved here:

[D] 3r2k1/p1R3pp/8/nP3p2/4p3/7P/4QPP1/q1B3K1 b - - 0 29

with 29. .. h6 instead of 29. .. Qa4? 30. Kh2! and
White is winning.

Arasan had Crafty in round 4. Crafty played a fairly harmless Bishop's Opening. In the middlegame Crafty misplaced its pieces and wound up losing its loose a pawn. Arasan continued to gain advantage and won another pawn. But I was having intermittent Internet problems - Winboard kept going unresponsive even though the router appeared to be up and I could still ping the server. Finally Arasan disconnected for the 3rd time and was forfeited (Myrddin, which I was operating, forfeited too, but it was about to be mated anyway). Disappointing but it just goes to show anything can happen in a tournament.

The final position was this:

[D] 1r4k1/5p2/p4p1p/3p4/2n5/1p6/1P1NKPPP/1R6 b - - 0 43

It's impossible to be sure what would have happened from here, but
it looks to me like White is busted. Rybka expects Nxd2 44. Kxd2 Rc8
45. Rc1 Rxc1 46. Kxc1 when Black is two pawns up and should win easily.
If White resists exchanging Rooks, Black can play .. Rc8 and .. Rc2.

Next round Arasan had Black against Rybka. Rybka played the relatively
rare line 5. dxe5. The best reply is probably Nc5 as in
Navara-Kramnik, Prague 2008. But Arasan pulled the inferior line with
.. Be7 6. O-O O-O out of its book. That's what playing against a pro
booker does to you. Although White's king was exposed, Black really
had no counter-chances. Arasan's score stayed positive for quite a
while. After 27. Rg1 it failed low but Arasan still didn't see White's
attacking potential. After 37. Bb2+ Black's position suddenly fell
apart.

Last round was Arasan-Telepath. This was another Nimzo-Indian. Starting around
move 20, Arasan's score started to gradually climb. At this point:

[D] r5k1/4qppp/2bN1nn1/2P1p3/8/pr2PP2/3RB1PP/B1QR2K1 b - - 0 29

Black's position is already difficult but Telepath should maybe have
tried Bd5. Instead it played .. Nh8 and after
Bc4 Arasan has grabbed a key diagonal and gained a tempo to boot.
Arasan went on to win a couple of pawns and the game, which was
played out until checkmate.

Arasan was 3rd after Crafty + Rybka. It would likely have been
2nd if not for the Internet malfunction in round 4.