TsumegoFromGames170/Attempts

Black lives in sente  

Herman: This looks like it is the best black can do. Life in sente.

Any other move than results in all white's stones being captured. is necessary to live, otherwise Black can kill with the descent to a.

Reuven: Everybody who looks at it, comes up with this at first! :) But was the overall position shown, it'd be clear that B needs more than this (W is let off a bit easily here). And in fact, does have something significantly better!

Reuven: Ah sorry - What I thought was an unconditional kill, seems like a direct ko, afterall... Just when I thought I managed to avoid it, too... :( Btw, in this sequence, you could skip the 1-2 exchange, couldn't you?

ko  

Reuven: Like this Ba Wb is a ko. After it seems rather forced up to (If at , at would kill). B could try at but W would atari at c.