Common line - forced moves  

- is forced. It's easy to verify that allowing White to play at makes life. Next, is tesuji, making miai of a and b.

The corner tesuji

Life  

wedges and then is a splendid move. Whatever Black does, will do the trick. If Black plays the shape point , then is atari and next White lives at a. If Black responds to at , then White can play and make two eyes at b or c.

The center sequence

Life  

If defends on the left, then after , Black has a problem. White can play at a to get an eye at b or capture black, or at c to capture either black or black . See next diagram

Continuation  

After white threatens a capture on the left and a ladder on the right.

Variation 3  

Black gets caught in net. ignoring 5 does not lead to ko as white will force eye at 'a'