Difficulty: Beginner   Keywords: Go term

Ja-Choong-Soo (자충수 Revised Romanization: Ja-Chung-Su, McCune-Reischauer: Cha-Ch'ung-Su) is a Korean go term. It literally means "self filling up move", which we can polish as "a move that reduces one's own liberties".

See Minue's HaengMa Tutorial For Beginners for a definition at length.

Basic Example

Really stupid  

Example from [ext] this baduk site

B1 is a really stupid ja-choong-soo (except maybe as a losing ko threat), because it destroys the seki.

Example from Minue's explanation

Joseki mistake  

The beginning of the discussion starts with this joseki mistake. Typically, after W2, black will hane at a, white extends with W4, and black will play at b to make good shape. However in this example, black makes a mistake and plays B3. This is an example of ja-choong-soo, a self filling up move.

The point is that one expects a net growth of liberties for each move:

The black 3-4 stone has 3 liberties after the attachment. The two black stone group has three liberties after W4. Literally, there is no reduction in liberties. However, if we consider that a simple iron pillar increases liberties from 4 to 6 with the addition of the second stone, we can see that the second stone in the example mistake is a net decrease in liberties comparitively.

Ja-Choong-Soo last edited by MrTenuki on January 13, 2012 - 18:17
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