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KoFighting

Referenced by
ValueOfAMonkeyJump
KoThreatPlayingOrder
IfYouDontLikeKoDo...
ApproachKo
KoMonster
CountingProblem01
Corner12Connectio...
KoLoser
OG2M150HowBig

 

Ko Master
   

Professor Elwyn Berlekamp coined the term, komaster, for the person who can win a ko (or superko) without having to ignore a ko threat. The opponent is the KoLoser. It is possible, of course, that a ko has neither komaster nor koloser.

For certain kos, such as approach kos and ten thousand year kos, the count depends on who is komaster. Such kos, and similar ko positions, are called hyperactive. In some ko positions, who is komaster does not affect the count, but does affect the miai value; I coined the term active for such positions. Other ko positions are called placid.


Example of how who is komaster affects the count of an ApproachKo:

[Diagram]
Diag.: Black komaster

B 2 elsewhere. B 4 - W 5 = ko threat and response. B 6 takes ko. W 7 elsewhere.

If Black is komaster, White has nothing better than to make the approach move and convert this to a regular ko. Assuming that a is White territory, the local score is 14. Since this is, in effect, White's sente, that is the count of the original position.


[Diagram]
Diag.: White komaster

B 2 elsewhere. B 4 takes ko. W 5 - B 6 = ko threat and reply. W 7 takes ko. B 8, 10 elsewhere.

If White is komaster she can win the ko in 3 net plays, for a local score of -12. Black can win the ko in 1 play at a, for a local score of 15. (B 3 will be Black sente later. 4 plays make a difference of 27 points, so the miai value of the ko is 6 3/4, and this position has a count of 8 1/4. Who is komaster makes a difference of 5 3/4 points.



Note that the komaster won the ko after using only one ko threat. That threat was enough to make her komaster. If a komaster can gain from using additional ko threats to delay winning the ko, she is KoMonster.

--BillSpight



This is a copy of the living page "Ko Master" at Sensei's Library.
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