Live shape
A big eye that is not a dead shape.
One could also include big eyes that result in ko for life.
[edit]
Examples
- Bent Four - except in the corner
- Twisted Four
- etc.
Alex Weldon: In the middle of the board (and, I think, on the edge, but correct me if I'm wrong), any eye of seven points or more (where the surrounding stones form a single group) is a live shape. As always, special properties of the corner can change this.