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Basic Kofight Example
Difficulty: Intermediate
Keywords: Ko
Here is an example of a simple ko fight. Black has just taken a white stone at a. If Black manages to connect at a, his bottom group will live. Although there are only two territory points in it, if his group dies, then White will gain 25 points, so the difference between winning and losing the ko is 27 points. Since that is a difference of 3 plays, each play is worth on average 9 points by miai counting. White knows this as well so she tries to play a ko-threat.
This move threatens to make the white bottom left group alive again (If Black connects the right hand ko, White plays at
However, Black has a series of good threats and is confident of winning the ko, so he responds to the ko threat by playing at
Of course, Black cannot retake the ko, so Black plays
If White doesn't respond then Black plays
If White doesn't play
White should therefore answer the ko-threat at
In this diagram, White has no more ko-threats.
Black has another local ko threat at As can be seen from this sequence, White could not win this ko, since she had fewer ko-threats than Black. Kiko (5k): So really, assuming White saw she could not win the ko, she should not fight the ko at all. In the given sequence, she loses two/three stones on the lower edge unnecessarily. Like trying to save your stones by playing the first few moves of a ladder, and then realizing that it doesn't work: better not to have started it in the first place!
BillSpight: First, White does not lose any stones on the lower edge. The diagram was confusing. I have corrected it to show that
Second, there is what is called a ko exchange. White gets something in exchange for Black's winning the ko. Sometimes that occurs when Black ignores White's ko threat. In this case, where Black has more threats, that occurs when White gets an extra play somewhere else. This ko is worth nine points. Suppose that the ko arises when other plays are worth around seven points. Then we might get this kind of ko fight.
Black takes and wins the ko, and gets one move elsewhere, while White gets three moves elsewhere. If these moves are worth around seven points, White gains 14 points in exchange for the ko. But if White does not fight the ko, but just plays elsewhere after Black takes the ko, leaving the ko until the end of the game, then she will get only seven points in exchange for the ko. At the end she will just fill dame or pass while Black fills the ko.
(Actually, Needs WME? This is a copy of the living page "Basic Kofight Example" at Sensei's Library. ![]() |