3.6 Solutions

One solution is to play by territory rules, under which every unnecessary reinforcing move made inside your own territory costs you one point. Another solution is the following: Let's say that if Black fills the last neutral point in Dia. 3-7 he gets only half a point for that stone, and the other half point is given to White. If Black reinforces at 'a' then he will be the last to fill a neutral point, and will lose one point: half a point will be subtracted from his territory and added to White's. If White also makes an unnecessary reinforcing move somewhere in Dia. 3-7, then White will fill the last neutral point. Compared with Black's filling last, White will lose one point because no half-point transfer takes place. So if either player reinforces blindly he loses a point.

Dia. 3-7

Instead of talking about filling the last neutral point, we can say with slightly greater generality that half a point is deducted from Black's score and added to White's score whenever Black makes the last competitive move. This rule, known as the Taiwan rule, is an extremely interesting modification of area rules. In formulating this rule, the key problem is how to define the last competitive move. A concise but complete definition would be highly significant; it would put the finishing touch on area rules.