: ( 942)
Black will use the atari of in the hanezeki as a ko-threat just now, instead of connecting the hanezeki's tail.

FLAG E1: (A 946)
Black must avoid re-capturing the ko at a moment, when White's centre group has more than four liberties.

FLAG E2: (B 947)
Black does not have valid ko-threats on the left side, because White is able to simply capture the hanezeki's tail. Please remember that Black's group is below the Punishment Semeai Liberty Level.

:
Black's group is below the Punishment Semeai Liberty Level, so only those ko-threats are valid ones that threaten to torpedo White's capturing of the hanezeki's tail. If White captured at , instead, Black simply would capture at , and win.

:
However, reduced Black's liberties below the Punishment Semeai Liberty Level again, so Black must connect the hanezeki's tail with his next move.

:
Black does not have any single ko-threat left.

FLAG E3: (A 949)
As long as White's centre group has four liberties left, Black's atari at on the upper edge is no valid ko-threat.

FLAG E4: (B 951)
As before, there are no valid ko-threats for Black on the left side of the board. White's -group there, as well as White's centre group, has too many liberties.

:
White simply connects the ko. Black will be unable to give atari at .
White wins the main line of Joachim's ("late") ko-semeai.
Please note that White did not need to invest any "damage-threatening" ko-threats of her own. Simply occupying Black's liberties was sufficient to succeed, after she started the ko "late".