TsumegoFromGames55/Attempts

My attempt  

Grauniad: I don't see how White can live after a Black move at the same point.

Answer  

prevents ko and makes miai of a and b. This and move are not obvious to me, and I suspect there may be holes in the reasoning.

Different Answer  

Ed?: White is alive here at 'a' or 'b'.

ko  

ed?: here threatens to separate the the white stones by pushing through at . If the exchange of for is not sente then black can kill.

ko  

White throws in with to make a ko. White will play at either point 'a' to finish the ko.

Alternative for black 7  

White is alive here.

Alternative for black 5  

White is alive after

Increasing eye space  

If the exchange of for is not sente for white black can kill.

approach ko  

Black can get a sente seki by exchanging 'a' for 'b'. Playing 'c' instead leaves open the possibility of a ko. White 'b' in response to 'c' leaves a 1000 yr ko, although if white starts it early by throwing in at 'a' it is a direct ko for white but black will need a lot of approach moves. If black can play 'c' and white tenuki's, black 'b' makes it a direct ko.

This diagram seems to be white's best option.

Playing underneath 1  

Here white dies. at would give ko after black pushes through at .

Playing underneath 2  

'a' and 'b' are miai so white must fight the ko

Not clever  

Resisting with is clearly bad, white collapses.

Seki  

This attack leads to seki. at 'a' would lead to ko. Again white is dead if the exchange of for isn't sente.

Seki  

If at then white lives with territory at 2.

(Hicham): Isn't 4 atari?

Ed? True white needs to exchange 'a' for 'b' before playing