Cutting the sake bottle shape

    Keywords: Shape, Tactics
[Diagram]

Cutting the sake bottle shape

As one can see here, the sake bottle shape created by B1 in a can be cut at the weak point W2 in b, where Black’s weaknesses are marked circle. Black can, however, choose which two of his three stones to keep connected, by playing as in c or d, where the cut-off stones are marked black+circle.

[Diagram]

Another way to cut (ladder-breaker required)

Another way to cut is with the W2-W4 combination in e, which is only possible if White has ladder-breakers for both ladders starting at circle in e, to prevent Black playing f or its mirror image. If White does have such ladder-breakers, Black’s cut-off stones may need to escape – for example with B11 at black+square in g.

A third way to cut off one of the two bottom stones is shown in h; however, Black again gets to choose which and has the option of reducing this to f (or its mirror image) if, instead of defending with B3, he attacks at W4. Hence White again needs both ladder-breakers, in which case B7 in h does not capture W6.


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