White forces with and (the order of which is important) then with threatens to make a second eye: Black can't make it false at the marked point, because White will push through at a and take two stones. So he plays , upon which White connects at .
Surprisingly enough, White captures with and , making miai of replaying under the stones!! For reference ...
There are many opportunities for White to go wrong. Let's analyze some:
(To be continued - please contribute if you want.)
At , if White plays instead of a, Black answers at to keep White down to one eye. If next White captures two stones at a, he throws in at . White should capture simultaneously to make miai of Black's answers. The order of a and ( and White 11) is important.
If White plays at here (instead of connecting at ) Black captures at and the miai are destroyed.
If White changes the order of and , Black can answer at and make it ko with .
If the order of and didn't matter, then either one of the answers would be different.
But Black can answer at , then at as in this diagram. Next, White comes one move too late: after , a and b are miai.
Finally, what if White ataris from the other side ?
... the capture makes miai of a and b. So ?