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Illegal

Referenced by
BentFourInTheCorner
Suicide
Oshitsubushi
Move
WomenDiscussion
HardHeartedness
WhatIsGoAbout

 

Illegal Move
   

An illegal move is a move which violates the rules of go.

Typical illegal moves are

  • playing twice in a row
  • recapturing a ko without playing somewhere else first
  • playing a stone on top of another one
  • playing a move so that the group is left without liberties if suicide is forbidden.
  • playing in a way that the board position repeats, when the rules contain some variant of the super-ko rule.

Andrew Grant: Recently (on 2nd Oct. 2003) Cho Hunhyeon played an illegal move in a major tournament game and had to forfeit the game.

(Sebastian:) Which illegal move? There aren't many chances to do them in Go!

Andrew Grant: Cho played a non-capturing move on a point with no liberties.

[Diagram]
Cho Hunhyeon 9d v. Choi Cheolhan 5d. Kisung tournament.

B1 seems bizarre, but Cho was probably intending to take the ko at a and just played on the wrong point.

It's easy to make this kind of blunder if a ko is involved. Most likely Cho's mind was preoccupied with counting and evaluating ko threats, and he failed to pay due attention to the trivial task of taking the ko.

Something similar happened a few years ago in (I think) the Meijin tournament in Japan, where Cho Chikun took a ko without making a threat. But on that occasion the game was annulled rather than forfeited, since Cho had asked the referee if it was his turn to take the ko and the referee had answered wrongly.



(Sebastian:) Poor guy. I think that Go is too hard-hearted. (Ensuing discussion moved to hard-heartedness)

uxs: Black playing at a instead of at B1 seems bizarre too. White seems to be in such a better position there that black should just give up and tenuki, imho.



This is a copy of the living page "Illegal Move" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.