Knight's move net
Black to play and capture the stones.
There are quite a number of patterns of net; those built on knight's move relations are sometimes missed in games by amateur dan players. This less usual example is taken from a Korean book for use in schools.
After White can do nothing.
If is played one line closer, White can do plenty, and if Black resists White's escape, the
stones become weak.
David Foale: In the knight's move example, how can Black avoid a cut like this?
I come across problems like this every day and they're annoying to say the least! Or am I missing something? Got a feeling i'm making a fundamental defence error...
Joonas Tyystjarvi: the cut here doesn't really matter, since the white stones inside are captured. is better left unplayed - black could play straight at a (or b, if he wants to capture fast).
David Foale: I know the stones are dead, but nevertheless the cut annoys Black; those two stones could be a problem if White has thickness to the bottom. is there any way to avoid this?
Joonas Tyystjarvi: with a net, there's usually no way to avoid some kikashi - in this case, you could say that is a forcing move. Also see my earlier comment - there's no need to force White to make a two-stone group. If
is at a, black threatens a ladder capture, and if White plays
to prevent that, he becomes heavy.
Charles: Whether or not will turn out to have some value to White is not yet clear. White has some threats round here; but playing them clumsily may well increase White's local loss.
By the way, whether Black's atari is good would depend partly on whether here is playable. Let's make this Knight's move net/Reading question.
Another, harder example is at Shape Problem 6/Net variation.