Re: [computer-go] Super Ko on KGS ignores player to move

["William M. Shubert" <wms@xxxxxxxxxx>]

John has it right. The chinese exact rules specify positional superko,
then they have generalizations that indicate that the TD may overrule
superko. The KGS source code of "Rules.java" contains this function:

  public final int getKoType() {
    if (type == JAPANESE) {
      return(KO_SIMPLE);
    } else if (type == CHINESE) {
      return(KO_SAMEBOARD);
    } else {
      return(KO_SAMESTATE);
    }
  }

Which is hopefully clear enough to a programmer to explain exactly what
to expect ("type" is a member variable of a rules description). When I
last researched this, I'm quite sure that it was correct, although since
then it is possible that one or more organizations have rewritten their
rules and I am out of date.

On Sat, 2005-08-13 at 13:48 +0200, john tromp wrote:
> On Aug 13, 2005, at 1:45 PM, Peter McKenzie wrote:
> 
> > I noticed this super ko rule a while back and decided to add a unit
> > test to my program to ensure it complies.  In designing my test I
> > tried to find the shortest possible game that had a superko.  Here is
> > what I came up with:
> >
> > a2 b1 b2 c2 b3 d1 a3 a1 c1
> >
> > Now the move b1 is illegal on KGS under Chinese rules (although legal
> > under all other KGS rule variants).
> 
> That's right. Chinese rules use the simpler positional superko,
> while AGA and NZ use situational superko, which also takes turn into  
> account.
> 
> So superko is a term that needs to be qualified...
> 
> regards,
> -John
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> 

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