I think the best Black can do is save some of his stones and let the left part get pinced off. White´s stones are protected by a snapback-threat to both sides. Correct? -- SvenB
unkx80: General idea is correct. However, White's moves are slightly suboptimal. The hint is "snapback", which is in the title of the problem.
Hmmm... I don´t see how White could prevent Black from saving the right half - what am I missing? -- SvenB
unkx80: Actually, you can't prevent Black can saving the stones on the right half. I mean there is an even better way for capturing the stones on the left half.
Shaydwyrm: If black resists with , creates a snapback. Black can't capture at a because white will then capture at b leaving black dead in the corner. I took Bill's suggestion for extending the right side of the problem in order to clarify that b is not the edge of the board, so capturing there does not create a ko. I don't know if anyone else was confused by that, but I was...