Flying Saucer Shape

    Keywords: Life & Death

The Flying Saucer Shape is dead

[Diagram]

The Flying Saucer Shape is dead

The critical elements are

  1. the black group's weak spots are occupied by white (WS stones),
  2. the black group is blocked the second line at both ends (WC stones), and
  3. these white blocking stones are connected to the rest of the white group (W1 and W3).

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

[Diagram]

Attempt 1

White cuts at the other side than the one Black protects, then gives atari. She finishes off with W6, keeping Black at one eye. The position is symmetric, so if B1 at 3 then W2 at 5.

[Diagram]

Attempt 2

Black ends up with a 3 point big eye with W2 already at the vital point.

[Diagram]

Attempt 3

After W2, Black has a shape similar to six on the second row. He's dead. B3 gives major resistance, but after W4, she can almost fill Black's eye space with three stones any time.

[Diagram]

Attempt 4

This reverts to attempt 3.

[Diagram]

Attempt 5

[Diagram]

Attempt 5 - alternative


[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.


This is a copy of the living page "Flying Saucer Shape" at Sensei's Library.
(OC) 2007 the Authors, published under the OpenContent License V1.0.
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