Eyespace

Eyespace^[1] is, informally, the space available for a group to make an eye or eyes. In practice, eye space consists of points on the board almost or entirely surrounded by a player.^[2] In tsumego problems, it is often important to reduce the eye space from the outside, for example by a hane.

In the early stages of a game, a group's eye space is provided for by the group's base, giving eye potential. For eye spaces that are effectively surrounded by one colour, their quality depends on their eye shape.

See also

• Base
• Eye Potential
• Eye shape
• Eye shape, Eye space - Discussion
• Formal Definitions Of Eye
• /Jasiek's formal definition of eyespace
• There is death in the hane
• Two eye formation
• Eyespace Values in Go by Howard Landman

[1] Eyespace is a term used also by Howard Landman in his paper Eyespace Values in Go. Unlike "eye shape", the more frequent spelling is as one word: eyespace.

[2] 'Eyespace' in English is synonymous to 'futokoro' in Japanese. However, in Japanese vernacular 'futokoro' means 'pocket', and in go is less general than English 'eyespace'. Futokoro is surrounded, or nearly so, by stones of the group attempting to make eyes.