False Eye

  Difficulty: Introductory   Keywords: Life & Death, Shape, Go term

Chinese 1: 假眼 (jia3 yan3)
Chinese 2: 卡眼 (qiǎ yǎn) - to falsify eye
Japanese: 欠け眼 (kakeme)
Korean: 옥집 (okjib)

A false eye is something which possibly looks like an eye, but really isn't one.

[Diagram]
One eye is false  

The black group has a real eye and a false eye. The false eye is the one at a. Notice that the marked black stones have an incomplete connection with the rest of the group: a suffers from both marked white stones.

Also, if White fills up the exterior liberties at b and c, the two black stones are in atari. If Black connects them at a, the "eye" obviously disappears. Just the same if Black allows their capture.

Thus, a false eye is not an eye.


There are four basic types of false eyes (see also recognizing an eye) :

[Diagram]
Diagonal false-eye  
[Diagram]
Bottleneck false-eye  
[Diagram]
Side false-eye  
[Diagram]
Corner false-eye  



False eyes are fundamentally bad shape, and they can be taken advantage of in order to reduce eyespace or cause shortages of liberties.

[Diagram]
False-eyes are detrimental to eyespace  

This White group may seem alive at first glance, because it seems to have more eyespace than a straight four group, but it actually has less and is unsettled !

[Diagram]
Kills  

B1 kills, next a and b are miai. (B1 at a also kills.)

[Diagram]
Lives  

W1 lives.

[Diagram]
Also unsettled  


Also, forcing the opponent to create false eyes is a very common technique to reduce the number of liberties of a group. Squeeze tesujis and capturing problems very often involve false-eyes.

[Diagram]
Black to save his corner stones  
[Diagram]
Solution  

After B3, the marked stones are captured.


See also:


False Eye last edited by Timm on April 2, 2015 - 05:31
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
RecentChanges
StartingPoints
About
RandomPage
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Goproblems.com
Login / Prefs
Tools
Sensei's Library