Alternating play

    Keywords: Ko, Rules, Theory

In the game of Go, players alternate turns. A turn can be a move or a pass. When analysing a global board position or a local group status we assume players alternate moves.


On the other hand in considering play on a sub-board we can and should try to understand the effect of tenuki plays, which break up the alternating pattern. When play isn't alternating in a local situation, the balance of plays there can become one-sided (as measured by the local tally). This often happens, for example in ko fights: the ko rule prevents alternating play, and follow-ups after the ko is dissolved are common.

The same effect can be achieved on a full board by using the rules for environmental go.


axd: I'm not sure if there is a page that describes the procedure to follow when a group's status is contested? once the game is finished. As far as I know, in such a case, players resume the game and play alternatingly around the contested group; passing is not allowed then, as it would influence the end score. Can anyone confirm this?

Bill: This situation is handled differently by different rules. Among current official rules, AGA Rules and Ing rules have clear procedures for continuing play in such cases.

axd (13k): reading the Ing rules draws my attention to the word disputed?, see also

Question About Japanese Scoring
has lengthy discussions about what to do - I (reluctantly) decide from there that the obligation to play an equal number of moves (i.e. not passing) is not essential. But I also understand that this is a dark area of the rules. A bit disappointing for someone who thought Go was simple :-)
Japanese Counting
some procedure exists...
Japanese Rules/Discussion
use a separate board to decide on the status of a contested group
Scoring/Discussion
Bill suggests playing out, including pass stones
Territory and Area Scoring
There are territory rules that allow disputes to be settled by play, such as the Lasker-Maas rules and Spight rules.

Quite disappointing (yes, welcome to the game, I know :) ... Not quite certain, but I believe I lost a potential (and most probably brilliant) Go player because he might have had problems with such issues.

Bill: You should have played him using area scoring, such as AGA rules. Even if you are used to territory scoring, the transition should be easy for you.



This is a copy of the living page "Alternating play" at Sensei's Library.
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