: ( 273)
Black connects in the upper left corner, which is not correct, and will lose a point.

:
This move creates ko-threats for the forthcoming endgame ko.

Ko: ; ; ; ;

:
Black cannot win the final ko on the left side. Black has eight ko-threats () available, as many as White has (). It's Black's turn to take the ko, so Black would need at least one ko-threat more than White to win this ko.

White wins this sub-variation by two points.

However, if Black did not play any throw-in in the hanezeki, White would have two prisoners less, so the game would end in a draw.