Basic living eye shapes
Four points in a row
Four points in a row, (whether straight four, bent four or twisted four), are enough to live.
In the straight four, and
in the diagram are miai.
Five-point eye shapes
Five-point eye shapes are alive except for the crossed five and the bulky five. Some examples:
Six-point eye shapes
Six-point eye shapes are alive except for the rabbitty six. An example is rectangular six.
Seven-points eye shapes
Almost all eye shapes of seven points are alive. See the Bulky Seven shape.
This shape (butterfly seven) is one that seems most likely to be killed, but after the position is seki.
Damien Sullivan All this is good, but I've had interest in minimal living shapes which aren't fully surrounded yet and may be peeped at. Assumptions: group is trying to live in place, not run away; all cuts work for white.
Black's ponnuki in the corner is alive, though it will have to respond to descents.