Late endgame exercise - Fujitsu 8 Game 9

Event: 8th Fujitsu Cup  on Jan van der Steen's web site
Round: 1
Date: 1995-04-01
Black Player: Yang Chae-ho
Black Rank: 9 dan
White Player: Komatsu Hideki
White Rank: 9 dan
Komi: 5.5
Result: W+3.5

Position at the end of the game record  

Black has to play in his own territory to prevent seki. Do you see where?

Solution