To determine the strength of Gobble we had it play several games on the 9x9 board against Many Faces of Go, the excellent go program by David Fotland. Many Faces of Go has earned a 12 kyu rating in hundreds of games against human opponents on the Internet Go Server. In 1986 [10], Fotland writes, ``I would love to have other computer programs to compete with. ... It is hard for me to tell how good it really is.'' To have Many Faces of Go available (public domain, xgo.s800, rev. 7.34) has been very helpful since it provides a strong, unvarying opponent. Table 1 shows the results of twenty games with Gobble playing Black at different handicaps and Many Faces of Go playing White at level 10 (medium strength).
For strategy A, Gobble played 500–1000 games to find its moves. Strategy B is an extension of strategy A to the first halfmove. In the left column for strategy B, 400 games were played and then the 4 best moves performed and evaluated with another 400 games each. In the rightmost column, games 1 to 3 were played with 500 games per evaluation and 3 trial moves, and for games 4 and 5 the number of games was doubled. Handicap stones are placed on the star points.
One should keep in mind that such a small sample can only give a rough overview. The sample is representative in the sense that except for a few test games used to adjust the parameters all games the author had time to play are shown. The scores vary a lot because the players are weak by human standards, and the boardsize is small. Nevertheless, there is clear and perhaps unexpected evidence that Gobble plays respectable novice computer go. Gobble's strength for strategy B seems to be in the 20 to 25 kyu range.
Strategy A requires three handicap stones to have a chance against Many Faces of Go, but although this is a huge advantage, Gobble displays a basic capability to stay alive and also to kill its opponent. Strategy B brings an improvement of about one handicap stone. Gobble's strategy, stated in general terms, is to build a strong center, while Many Faces of Go tries to increase its influence along the borders. Gobble only wins a game if it succeeds in cutting off and killing one of its opponents groups. Otherwise, Many Faces of Go wins because of its superior territorial skills.