Some notes on Arasan games in ACCA America tourney

[jdart]

Arasan played in the recent ACCA Americas' Computer Chess tourney
(http://taccl.org/ACCAChampionships/ACCA ... Champ.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.

[michiguel]

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.

Ouch. That hurts...

Miguel

[fern]

Steadily and slowly your program climbs to the summit.
My congrats
Fern

[Rolf]

Miguel

Congratulation for the fine play of Gaviota against Crafty. Although with only half the time rest. As a human I wouldnt have defended so well against the pressure on f-file! -Rolf

[jdart]

We had talked about playing the round 4 game out unofficially, although Bob had some concerns about repeated resuming messing up the learning function. At the time we had some difficulty resuming it but this morning I was actually able to get it to resume and Arasan did go into the pawn endgame and win, as I predicted:

[Event "?"]
[Site "chessclub.com"]
[Date "2009.11.16"]
[Round "?"]
[White "crafty"]
[Black "Arasan 11.6"]
[Result "0-1"]
[ECO "C55"]
[WhiteElo "2678"]
[BlackElo "2516"]
[TimeControl "2700+10"]

1. e4 e5 2. Bc4 Nf6 3. d3 Nc6 4. Nf3 Be7 5. O-O O-O 6. Re1 d6 7. c3
Na5 8. Bb5 a6 9. Ba4 b5 10. Bc2 c5 11. Nbd2 Re8 12. Nf1 Bb7 13. Ne3
Bc8 14. Bd2 Bd7 15. a4 Qb8 16. Nf5 Bxf5 17. exf5 b4 18. cxb4 cxb4
19. Rc1 Qb7 20. Bb1 h6 21. Kf1 Nd7 22. d4 exd4 23. Nxd4 Bf6 24. Qg4
Rxe1+ 25. Rxe1 Ne5 26. Qd1 Nec4 27. Bc1 b3 28. Be4 d5 29. Bf3 Rd8
30. Bh5 Rb8 31. Qd3 Qb4 32. Rd1 Qxa4 33. Qg3 Be5 34. Bf4 Bxf4
35. Qxf4 Qb4 36. f6 Qd6 37. Qxd6 Nxd6 38. Bf3 Ndc4 39. Ra1 Nd2+
40. Ke2 Nxf3 41. Nxf3 Nc4 42. Rb1 gxf6 43. Nd2 Nxd2 44. Kxd2 a5
45. Ra1 Rc8 46. Rc1 Rxc1 47. Kxc1 a4 48. Kd2 d4 49. Kd3 Kh7 50. Kd2
Kg6 51. Kd3 Kf5 0-1 {crafty resigns}

[michiguel]

Miguel

Congratulation for the fine play of Gaviota against Crafty. Although with only half the time rest. As a human I wouldnt have defended so well against the pressure on f-file! -Rolf

Thanks, I was sweating bullets. I will post later a couple of positions that are interesting.

Miguel