In a locale, a player's
- 0-territory is his current territory,
- n-territory is his current territory he does not have after n - 1 but has after n successive plays of his.
Usually in practice, only 0-territory and 1-territory are needed. Points of 0-territory contribute 100% while points of 1-territory contribute only 50% to a count.
The terms have been invented in Joseki Volume 2 Strategy to assess outer parts of territorial framewords, to compare different degrees of influence and thickness and to define general, theoretical models of both. Besides n-territory had previously been applied in iterative yose calculations but did not have a name yet.