Life In 19x19

Hi All ,

I have a question regarding rabbitty-6 shape:


I saw on youtube video that if white places at A then black is dead (e.g. A is considered the 'vital point' of that 'rabbitty-6' shape)... yet I wonder if subsequently black placed at 'D' and white 'flubbed' and then black also managed to place at 'C' -- doesn't that make a 'second eye' and resurrect the shape, even though 'vital point' / A is occupied by white?

Yes. When we say X kills a group, we assume correct alternating play from both sides subsequently. Sometimes there will be no moves which threaten to live that need answering (e.g. when you kill straight 3), but sometimes as here there are threats which need answering correctly to keep it dead. If the players aren't total beginners then the more likely scenario for the black group to come back to life after white A is if black played D as a ko threat, white ignores to win the ko, and then black got C to live. That's why if you are black and white plays A you shouldn't immediately play D and hope your opponent is stupid, but read ahead and see D then C keeps you dead so save D for a ko threat for a future ko which might arise.