(Referenced by 160)

///:

:
It might be tempting, but Black should not use this ko-threat in the hanezeki.

Ko: ;

:
Black lost a move by this exchange, so White is able to play another protective move on the left side, to pre-empt all of Black's ko-threats there.

:
Black's last move was no valid ko-threat, so White connects the ko.

:
The end comes earlier than without Black's mistake in the hanezeki.