Flying Saucer Shape
The Flying Saucer Shape is dead
The critical elements are
- the black group's weak spots are occupied by white (
stones),
- the black group is blocked the second line at both ends (
stones), and
- these white blocking stones are connected to the rest of the white group (
and
).
It is not critical whether the circled liberties are occupied or not.
For an example of a flying saucer position where the third critical element is missing, see Kanazawa Problem 23.
For a general treatment, see Two Space Notchers Not Fully Connected.
Black Attempts to Live
White cuts at the other side than the one Black protects, then gives atari. She finishes off with , keeping Black at one eye. The position is symmetric, so if
at 3 then
at 5.
After , Black has a shape similar to six on the second row. He's dead.
gives major resistance, but after
, she can almost fill Black's eye space with three stones any time.
[1] I made up the term Flying Saucer for this shape myself and I'm not convinced it will make history. I just needed a pagename a bit catchier than Two Space Notcher With Both Weak Points Occupied. Dieter
Bill: It's a catchy term, Dieter. I like it. :-) I hope it catches on.