This problem looks so comparatively simple. (It's unsolved...) I'll try!
Black plays first and gains. (Let's never mind how Black even got the privilege of playing first in this problem.)
White blocks in Sente and gets the other gap. Six takes the vital point of the Bulky Seven in the corner. On second thought, starting with the Hane on the bottom may have been better.
Five is a hasty inside play. Seven insists on living inside. Eight looks for more fighting liberties. Ten raises the stakes. The inner white stones depend on the Ko and White has local Ko threats starting with A. Depending on the circumstances this might be playable.
Black has another Ko threat at A. White's chance of winning the first stage is one third. If White wins, Black plays at A, White connects at B and Black takes back the Ko. White's chance of winning the first stage again is one third. If White wins the first stage, White's chance of winning the second stage is one third. White's chance of killing the whole group is one twenty seventh. White can also connect at Seven after taking the first stage leaving the other as a ten thousand year Ko. This is slightly more likely to work with one ninth... (By the way, Five dies.)