White neglected to play and a black move there killed the corner. However, backing up a bit, should White be able to live here?
If Black had played here instead, the sequence in the previous diagram would not work for White.
I fail to see how White can live. Can she?
Backing up further, here is the essence of the shape.
In the diagrams above, Black had made some forcing moves to disconnect and from the corner. I show this shape to raise the more general question about what variations exist for Black here. was played to coordinate with a Black star point stone in the upper right. Prior to this game, I had not seen the - combination before so I had to invent a strategy on the fly. I opted to seal off and , thinking I'd then kill the corner. But, had White not made an error, the corner would have lived. Was Black's strategy sound? Should the corner die if it is disconnected from and ?
Andre Engels: To understand more of zook's comments, please note that in the game sequence, black could have killed white with the combination of and . I myself would have played in zook's first diagram at , but it seems that both moves kill.
Thanks André, i had forgotten to come back. So here's the completed second diagram. is necessary to make an eye around , but then makes leaves a and b as equivalent. --Zook
Next Black can aim at the + combination, putting White into trouble.
Thanks Charles. So if White insists on living in the corner, I suppose one might expect the following.
Black might finish off by playing a for a very thick position. Depending on the position, perhaps a could be omitted for now. Notice that is very well placed, allowing Black to run to the edge. This partly explains the value of this two space low pincer. A more or distant or higher one would not work as well.