Arasan games from WCRCC

[jdart]

Arasan had a hard time in a couple of games, despite being on an 8-core machine.

It was in a drawn position against Almond, but here at move 92:

[D] 2b5/1pk1r1p1/p4p2/P2p1P1p/3N2rP/2P1PRP1/3K4/1R6 b - - 0 91

Arasan went wrong with 91. .. g5 and got into an inferior endgame, despite having even material. Other moves seem fine, for example Rge4.

This is mysterious because I couldn't seem to get it to play g5 when I tried the same position on my quad Windows box. I'm still looking this game and probably Arasan made other errors - its endgame play needs some work.

I don't know much about Almond but is doing reasonably well in the tourney.

In the game against Tornado, Arasan was a pawn down in the endgame but had an advanced passer. For a long time Arasan had an even score. At this point:

[D] 8/3k4/8/b2B1p1P/4p3/p4p2/P4P2/5K2 w - - 0 61

Arasan played h6, and its score dropped to about -1.4. But this position may be still be drawn. The real error seems to be later, at move 69:

[D] 8/6bP/4B3/5p2/8/p3kp1K/P7/8 w - - 0 69

Here Arasan played Bc4, and after .. Kf2!, White is lost. But Arasan didn't fail low until the next Black move, move 70.

The only saving move appears to be 69. Kg3, which seems to still draw.

Both programs were hitting 20+ ply depths so this seems to be just a case of horizon effect.

[Kirk]

Arasan had a hard time in a couple of games, despite being on an 8-core machine.

It was in a drawn position against Almond, but here at move 92:

[D] 2b5/1pk1r1p1/p4p2/P2p1P1p/3N2rP/2P1PRP1/3K4/1R6 b - - 0 91

Arasan went wrong with 91. .. g5 and got into an inferior endgame, despite having even material. Other moves seem fine, for example Rge4.

This is mysterious because I couldn't seem to get it to play g5 when I tried the same position on my quad Windows box. I'm still looking this game and probably Arasan made other errors - its endgame play needs some work.

I don't know much about Almond but is doing reasonably well in the tourney.

In the game against Tornado, Arasan was a pawn down in the endgame but had an advanced passer. For a long time Arasan had an even score. At this point:

g5??

SOS and Shredder Solid had Kd6

15 0:15 -0.15 1...Kd6 2.Rb6+ Ke5 3.Kd1 (9.461.081) 618
15 0:20 0.00 1...Bd7 2.Kd3 Re5 3.Rb4 Kc8 4.c4 dxc4+ 5.Rxc4+ Kd8 6.Rf4 Rxf4 7.exf4 (12.508.153) 622
15 0:20 0.00 1...Rge4 2.Kd3 Bd7 3.Rb3 R4e5 4.Ke2 Re4 5.Kd3 (12.764.846) 622

[Kirk]

Arasan had a hard time in a couple of games, despite being on an 8-core machine.

It was in a drawn position against Almond, but here at move 92:

[D] 2b5/1pk1r1p1/p4p2/P2p1P1p/3N2rP/2P1PRP1/3K4/1R6 b - - 0 91

Arasan went wrong with 91. .. g5 and got into an inferior endgame, despite having even material. Other moves seem fine, for example Rge4.

This is mysterious because I couldn't seem to get it to play g5 when I tried the same position on my quad Windows box. I'm still looking this game and probably Arasan made other errors - its endgame play needs some work.

I don't know much about Almond but is doing reasonably well in the tourney.

In the game against Tornado, Arasan was a pawn down in the endgame but had an advanced passer. For a long time Arasan had an even score. At this point:

[D] 8/3k4/8/b2B1p1P/4p3/p4p2/P4P2/5K2 w - - 0 61

Arasan played h6, and its score dropped to about -1.4. But this position may be still be drawn. The real error seems to be later, at move 69:

[D] 8/6bP/4B3/5p2/8/p3kp1K/P7/8 w - - 0 69

Here Arasan played Bc4, and after .. Kf2!, White is lost. But Arasan didn't fail low until the next Black move, move 70.

The only saving move appears to be 69. Kg3, which seems to still draw.

Both programs were hitting 20+ ply depths so this seems to be just a case of horizon effect.

Both Solid and SOS played with Bc4 for awhile

Solid stayed with Kg3 after awhile

[jdart]

> Both Solid and SOS played with Bc4 for awhile

> Solid stayed with Kg3 after awhile

After Bc4? Kf2! Black actually has a forced mate, in 40 moves or so.

--Jon

[jdart]

I have posted some annotated games here:

http://arasanchess.org/games.shtml

A couple more notes -

After the the loss to Almond in Round 3 in a drawn endgame, I suspected something was wrong. So for the round 6 game against Tornado I switched from the 8-core Linux box to my Windows quad. Arasan lost that game, too, though.

Then for the remaining games I went back to the Linux machine but I disabled history pruning, which I've put in rather recently (Arasan 11.7 does not have it). I didn't see any more real blunders. Arasan went down very quickly and decisively to Rybka but it had a big hardware advantage, not to mention the software! So overall Arasan did ok after a shaky start.

[Kirk]

> Both Solid and SOS played with Bc4 for awhile

> Solid stayed with Kg3 after awhile

After Bc4? Kf2! Black actually has a forced mate, in 40 moves or so.

--Jon

Stranger is The Triple Brain chooses Bc4 over Shredder Solid's Kg3!

[Kirk]

I have posted some annotated games here:

http://arasanchess.org/games.shtml

A couple more notes -

After the the loss to Almond in Round 3 in a drawn endgame, I suspected something was wrong. So for the round 6 game against Tornado I switched from the 8-core Linux box to my Windows quad. Arasan lost that game, too, though.

Then for the remaining games I went back to the Linux machine but I disabled history pruning, which I've put in rather recently (Arasan 11.7 does not have it). I didn't see any more real blunders. Arasan went down very quickly and decisively to Rybka but it had a big hardware advantage, not to mention the software! So overall Arasan did ok after a shaky start.

Arasan has come a long way!