Value of a Ko Threat
Keywords: Ko
Several possible meanings.
- Black makes a ko threat, White ignores it, Black follows up the threat and White feels obliged to answer that play, leading to a settled position. Count the swing that makes, based on comparison with the ordinary plays in that part of the board. That number is the value to Black of the threat.
- Valuation, probably approximate, in the same context as 1 but open-ended (no assumption that White answers Black's follow-up so that Black emerges with sente).
- Valuation of a 'ko threat not intended as a threat', plus a second such, ie of Black making two plays in a row while White captures and finishes the ko.
One can also speak of the value of a ko threat that is answered. If the move played as a threat was for example a one-sided sente endgame play, its value isn't normally of serious importance (it was anyway the prerogative of the player). If the value is negative - the threat is loss-making - that's something to be taken very seriously before playing it.