Ko:

(Referenced by 250)

: ( 418)

!!! Please assume - for demonstrative purposes - that Black has further ko-threats on the left side of the board. We have added the marked Black stone for a more plausible scenario. !!!

Ko: ; ;

:
White does not have own ko-threats any more, so she pre-empts further Black ko-threats on the left side.

:
Black's internal ko-threat is decisive here.

:
Black captures the ko for the last time. He will give atari at with his next move, and win the game.

Please note that White's original move at - capturing Black's nakade stones - is the only option that White has to pre-empt Black from gaining at least the two additional ko-threats of this sub-variation.