# # # # # # # . . . # # A # O . . . .
O # O # . # O # # # O # # # O . . . .
. O . O # O O # O O O O O O O . . . .
O O O O O O # O O , . . . . . , . . .
# # # # # # # . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .
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As it stands, this position has balanced liberties, and neither side may
start the ko. But Black may play at A, after which the internal liberties
no longer balance and he may fight to capture White's corner stones.
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# # # # # # # . . . # . A # O . . . .
O # O # . # O # # # O # # # O . . . .
. O . O # O O # O O O O O O O . . . .
O O O O O O # O O , . . . . . , . . .
# # # # # # # . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .
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Here Black may play at A and then fight the ko. It is debatable whether
Black is entitled to start the ko in the position as shown, without first
playing at A. It is clear that White A is a good move in this position,
as it will now take Black two moves to attain a position in which he may
start the ko.
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