Monochrome shapes in black-and-white
Charles This is a point that has come up a couple of times recently on SL (I'm thinking of the big bulge and sake bottle shape pages). It's something fairly evident, but perhaps rarely formulated.
There are shapes of one colour that have names, and then a question about how many stones of the other colour one can add and still usefully apply the name.
We know that the empty triangle must be empty!
We can only call this black formation an empty triangle if there is no white stone at the circled point.
We would only call this a bamboo joint in case both circled points are empty.
In general, it seems, there are some covert 'rules' about the sensible matching of patterns with shape names.
Sebastian: What about the knight's move - do the squared points have to be empty?
Charles I say yes. So I don't like the keima attachment page title.
Sebastian: But this is always a kosumi, regardless of what's on the squared points?
Charles Pretty much: see also diagonal attachment.