Symmetric Evaluation

A possible strategy would have been to given the evaluation function a set of terminals which would provide access to each individual square within the board. Although this is a viable strategy (albeit slow), it does not take advantage of the inherent symmetry of the board position. For example, if a player should determine that the (2,2) point is not a good play during the early and middle game, then it is reasonable to assume that this holds true for the (7,2), (2,7), and (7,7) points as well.

Therefore, the board has been divided into a slice covering one eighth the board as follows:

This slice is then replicated seven more times over the board. Terminals are then provided to access each independent element of this slice. To determine the number of white, black, or empty pieces, three sets of terminals have been provided for each slice element. There is therefore a total of thirty new terminals, letted from 'A' through '^'. The legend below explains each terminal and its location within the slice.


The addition of these terminals immediately revealed Edgar as a fairly weak player. Unuasually simple trees were able to beat it. The following tree won with a score of 38 to 26 against Edgar. Many such one-leveled trees were observed. However, it was interesting to note that these one level trees were initially obtained from penalizing complexity (length). Even after removing the penalty, the species still often produced simple one-level depth trees which were sufficient to beat Edgar. It therefore appears that Edgar has many inconspicuous, but significant, flaws which can be profited from.