Twenty-third KGS Computer Go Tournament

Sunday February 4th, 2007

Rules

Format

Formal division: eight-round Swiss.
Open division: six-round Swiss.

Times

The first round started at 09:00 UCT for the Formal and 09:05 for the Open division.

Results

As usual, the tournament was held in two divisions, Formal and Open, with more restrictive entry conditions for the Formal division.

IdiotBot also registered for the Open division, and agreed to withdraw if this would make the numbers even.

The "real" names of the bots listed above, and of their programmers, are listed here: programs which have registered for KGS Computer Go Tournaments.

General

GNU played in both divisions. The version in the Formal division was the standard development version. The one in the Open division, MonteGNU, was a version modified to use a fairly standard and unsophisticated UCT search restricted to choosing among the moves normal GNU Go move generation would consider.

Formal division

In round 1, AyaBot won an interesting game against GNU. MoGoBot13 had an easy win against firstgo.

In round 2 MoGoBot13 outplayed AyaBot until it was clearly ahead, and then played moves that it knew were sufficient to win, allowing AyaBot to catch up and reduce the score difference to half a point. Meanwhile valkyria19 resigned against GNU.

In round 3, GNU, playing against MoGoBot13, played the marked move in the diagram. This is a blunder, as it abandons the group at the right. White could have saved this group by capturing at N1: Black must play at M2 to prevent it from making two eyes there, and then White plays at K3, capturing either K2 or K4 for another eye.
    Black correctly took advantage of the blunder by playing at K3, ensuring the death of the white group.
    I am grateful Sanghyeon Seo for supplying this analysis. I had misread several aspects of the fight in an earlier version of this report. He also reported on GNU's "thoughts": it was aware of the need to make two eyes, but failed to see the consequences of black K3.
    Two things impress me about this. One is that GNU read the fight better than I did (I am rated at 2-kyu). But more significantly, MoGoBot13, a UCT program, read it better than GNU did, despite GNU's having an explicit understanding of eyes.
    Meanwhile, valkyria19 was beating firstgo when valkyria19 crashed with an unknown bug.

In round 4 firstgo beat AyaBot. Valkyria19 resigned against MoGoBot13 before MoGoBot13 got into its "win by half a point" mode.

In round 5 valkria19 beat AyaBot, which was playing significantly worse than it does in events with longer time limits. GNU beat firstgo convincingly.

In round 6 MoGoBot13 played GNU again. MoGoBot13 twice showed no interest in fighting a ko which could have won it the game; GNU killed a group and won the game. This was MoGoBot13's only loss.
    Meanwhile AyaBot beat valkyria19.

Open division

In round 1 Orego showed some competence in fighting a ko against WeakBot50k.
     Unfortunately three of the four games in this round ended with status arguments, and not all of the the bots playing are able to do the game-end clean-up correctly. MonteGNU in particular suffered, failing to kill any of HBotSVN's four one-eyed groups, and losing the game as a result.

I did not notice anything remarkable in the next seven rounds. Bots continued getting the scoring wrong because they were unable to clean-up properly; and MoGoBot won all its games.