This is the version of the page on 2006 October 16.
A nakade (ナカデ or 中手) is a play inside an opponent's eye.
(Written in katakana or kanji in Japanese. Hiragana is wrong. Borrowing is not the only criterion for katakana. Italicisation and replacement for kanji are other uses.)
The nakade sequence, - , makes seki.
Unsettled eyeshapes are those eyeshapes where a killing nakade is possible.
Basic living eye shapes are those where a killing nakade (in one move) is not possible.
Dead eyeshapes are those where a nakade is not needed to kill: the group is already dead.
Be aware however that these basic shapes ignore two major effects:
For several possible reasons, the eye shape may contain more enemy stones. Any eye shape which is filled with stones so that almost filling it with a killing shape is inevitable, is dead. These patterns are listed at killable eyeshapes.
A combination of both circumstances can be found at Biggest known eye space for which there is a nakade
Now neither group can approach at a without putting itself in atari.