Seventy-third KGS Computer Go Tournament

Sunday July 3rd, 2011

These results also appear on an official KGS page which links to the records of all the games.


format20-round Swiss
board size9×9
time9 minutes plus 10/30s


The first round started at 16:00 UTC.

Result table

Zen9 pachi ManyF AyaMC Czech Orego oakfo Simpl PNUGo Stone
W13R BJ9 W010R B114R B14R W113R B018R W12R B112R W120R W17R BJ15 W116R W15R B119R B16R W11156 B182 B117T 17218161½Winner
2pachi2 B03R WJ9 B110R W014R
W15R B017R W119R B17R W011R B115R W12R B113R W14R B116R W18R B120R B1616 W11860 W112 B112T 15½226148
3ManyFaces2 W04R B013R W118R B05R W117R B019R
W13R B010R W116R W16R BJ11 W18R W12R B114R W11224 B1158 W194 B1206 B17T 14½209120
4AyaMC B02R W012R B020R W07R B111R W015R B03R W110R B016R
W15R B118R W11R B114R B19R W113R W1424 B11714 W162 W18T B119T 13217106
5CzechBot B07R WJ15 B016R B02R W013R B06R WJ11 B05R W018R
W09R B112R W14R B117R B182 W11014 B12012 W134 B1192 W11T B114T 1120256½
6Orego12 B05R W019R B04R W016R B08R B01R W014R B19R W012R
W13R B010R WJ15 B122 WJ7 B1114 WJ17 B1182 B16T W113T B120T 181½37½
7oakfoam W06R B08R W020R B02R W014R W09R B013R B04R W017R B03R W110R BJ15
B111 W1710 B11912 W1122 B016R B15T W111T B118T 183½33½
8SimpleBot B01156 W0616 B01860 B01224 W0158 B0424 W01714 W082 B01014 W02012 W022 W011 B0710 W01912
B152 W11314 B11416 B13T W19T B116T 618918
9PNUGo W082 B012 B094 W0206 B062 B034 W0192 BJ7 W0114 BJ17 W0182 B0122 W116R W052 B01314 W01416
W14T B110T W115T 6169½
10StoneGrid W017T W012T W07T B08T W019T B01T W014T W06T B013T W020T W05T B011T W018T W03T B09T W016T B04T W010T B015T

In the table above,
   0 indicates a loss
   1 indicates a win
   J indicates jigo
   a superscript indicates the round in which a game was played
   a subscript shows how the result was determined:
      R for resignation
      T for time
      F for forfeit
      a number for the points difference after counting.
All the 0s, 1s and Js are links to the game record.

The numbers in the table do not add up as you might expect. This is because two entrants, not listed above, were removed after two rounds.

Twelve players entered. These included break9, and it was present on KGS earlier in the day, so I registered it. However it disappeared from KGS before play started, and had not reappeared by midway through round 2. Therefore I removed it from the tournament; and to keep the numbers even and avoid byes, I also removed WeakBot50k. This left the ten players shown in the cross-table above.


In round 1, StoneGrid obtained a won position against CzechBot, but then stopped moving, and lost on time. It continued to play throughout the tournament, but never made any more moves, and so lost all its games. I twice "kicked" it from the server, in the hope of waking it up; each time it reconnected after five minutes, but still did not move. Its author John Fan later emailed me "It seems the StoneGrid got stuck into an infinite loop in the first game. I thought I had fixed it but it is still there. It does not occur often, but obviously when it occurs, it is a quite serious issue. And I am sorry for the inconvenience it had caused".

In round 8, CzechBot outplayed SimpleBot, and could easily have won by 48 points. However it preferred to suicide its group in a seki, and win by 2 points.

After round 8, all the players were on different scores: Zen9 8,  pachi2 7,  ManyFaces2 6,  AyaMC 5,  CzechBot 4,  Orego12 3½,  oakfoam 3,  PNUGo 23½,  SimpleBot 1,  StoneGrid 0.

Round 9 gave Zen9 its first non-win: a jigo against pachi2.

In round 10 Zen9 and pachi2 played again. (The pairing algorithm sometimes appears eccentric, but I, at least, am very pleased with the way it operates. It chooses the pairings which will be most informative about how the players rate against each other.) This time, pachi2 won.

Many Faces of Go vs Zen9
Moves 31-44

In round 18, Many Faces of Go and Zen9 played an interesting game. The final 14 moves are shown in the diagram to the right. After move 44, Zen9 resigned, it has lost the semai on the right side.

I should probably not comment, as I am considerably weaker than either of the players – but my impression is that move 31 was unnecessary. If instead Zen9 had played to connect on the right edge (between 32 and 35), Many Faces could have pushed at 31, starting a semeai between the two groups on the top edge, but I think Zen9 would have won this semeai.

Players receive points for the 2011 Annual KGS Bot Championship as follows:

Many Faces of Go3


Details of processor numbers, power, etc.

Aya, running on 6 cores of an i980X 3.3GHz
a development version of MoGo current as of 2010-10-06, running on an 8-thread i7 920, 6GiB RAM
Many Faces of Go, running on a 12 core Xeon
Oakfoam, probably running on an AMD Athlon(tm) 64 Processor 3000+.
Orego, probably running on one of the five nodes of a custom Linux cluster built by PSSC Labs: the node has two AMD Six Core Dual Opteron 2427 2.2 GHz (12 cores total), 8 GB RAM, Centos Linux.
pachi, running on 64 unspecified platforms, using 22 cores of each.
GNU Go, unspecified platform
running on one processor of a 4GiB RAM, AMD Athlon(tm) 64 X2 Dual Core Processor 4000+, shared with WeakBot50k
running on an Intel Core2 Quad Q9400 2.66GHz
Zen, running on a Mac Pro 8 core, Xeon 2.26GHz