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Eye versus No Eye Capturing Race
Path: EyesCollection   · Prev: EyeVersusEyeCapturingRace   · Next: NoEyeVersusNoEyeCapturingRace
    Keywords: Life & Death

If one of the groups has one eye and the other group not, there is no seki possible. We calculate the capturing race (semeai) as follows:

The eye party counts their outside liberties, their eye liberties and the inside liberties. The no eye party counts their outside liberties. The threshold thus becomes

OL1 + EL1 + IL = OL2

If the numbers are equal, the one who has sente kills the other. If one number is larger, the other party is dead already. The reason why eyes win semeais is that all inside liberties go to the eye party.

Example

[Diagram]
One eye versus no eye

At first glance Black seems to have more liberties than White (6 against 5). When we apply the theory, however Black cannot win the semeai even if playing first. a + b + circled points yields 5. The c points yield 4.



Remark: A complicating factor is that when there are big eyes (four spaces or more), the number of liberties also is higher than a naive count would suggest. See Four Is Five And Five Is Eight And Six Is Twelve or counting liberties for this effect.

See also the pages in the Eyes Collection.


Authors: Morten Pahle (10 kyu), Arno Hollosi (1 dan), Andre Engels (2 dan)

Revision by Dieter, so the original authors may now disagree with the content.



Path: EyesCollection   · Prev: EyeVersusEyeCapturingRace   · Next: NoEyeVersusNoEyeCapturingRace
This is a copy of the living page "Eye versus No Eye Capturing Race" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.