Temporary seki

  Difficulty: Intermediate   Keywords: Life & Death, Go term

In order for two or more groups to be in seki, the surrounding group(s) must be alive. Therefore, a temporary seki may refer to any of the following three meanings:

  1. An apparent seki but at least one of the surrounding group is dead. In this case, we say that the seki has collapsed, or that the seki is false.
  2. A seki where the surrounding group(s) are not unconditionally alive.
  3. A seki where a player decides to give it up as a ko-threat (e.g. an self-atari). Since this will then be a loss-making threat of quite serious proportions, it is not very common to occur in games.

When a seki is not temporary in the first or second sense, we say that that it is permanent.

Example of temporary seki in the first sense

[Diagram]
Temporary seki  

Although the black+circle and white+circle stones appears to be engaged in a seki, however, the black+square stones are dead. Hence, this seki is said to be false or collapsed.

[Diagram]
Proof  

To see why this seki is false, we see that White can play W1, W3, W5 and W7. Black can do nothing to prevent White from playing these moves and removing the black+square group off the board.

[Diagram]
Proof  

With the black+square stones taken off, it is now obvious that the remaining black+circle stones are plainly dead.


Example of temporary seki in the second sense

[Diagram]
Temporary seki  

Although the black+circle and white+circle groups are currently engaged in a seki, the black+square stones are not yet unconditionally alive. So there is always a distinct possibility that the black+square stones get captured later in the game. (A similar comment may be made for the white+square stones.) We say that this is a temporary seki in the second sense, and this seki may collapse.


Example of temporary seki in the third sense

[Diagram]
Starting position  

Suppose white+circle has just taken the ko in the fight to live. Note that there is a seki in the corner.

[Diagram]
Temporary seki  

If both Black and White is out of ko-threats elsewhere, Black may choose to play a loss-making threat at B1 and take the ko at B3. In this case, the seki in the corner was only temporary in the third sense.


See also


Temporary seki last edited by tapir on June 29, 2015 - 10:54
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