Empty triangle
This shape is an empty triangle, empty referring to the unoccupied point at . Most people like to say that the empty triangle is bad, being inefficient and prone to shortage of liberties.
In contrast, the full triangle, with a White stone at , is good shape. This does not stop the existence of it being the best move on the board in some situations - good empty triangle.
is a hane on the second line. Black may fear what happens if he blocks. In the left diagram he creates an empty triangle. Things get worse with
, wrapping around it and reducing the liberties to 3. In the right diagram,
forces
to connect and
creates good shape with three in a row.
Further reading
Elsewhere on the web
- Guo Juan's AudioGoLessons has
three audiolectures on empty triangles.
- Empty Triangle is also the name of a Go
comic strip.