Deiri Counting

    Keywords: EndGame

The value of a play indicates its importance or urgency. We may also use the metaphor of temperature. Larger plays are hotter than smaller plays. Normally you should play the largest play, but there are exceptions. (See tedomari.)

The two main styles of evaluating plays are deiri (DEH-EAR'-EE) counting and miai (ME-EYE') counting. Miai values directly indicate the urgency of plays, while deiri values do so indirectly.

Let me start with a couple of examples.

[Diagram]

Gote

If Black plays first she scores four points, represented as a positive integer, +4.

If White plays first she scores two points, represented as a negative integer, -2.

The deiri value is the difference between these two results (the swing), or 6 points.

We might call the deiri value of a play its swing value.

[Diagram]

Sente.

After B1, White must play W2 to live, and the net score is +2 (2 points of territory + 2 prisoners for black - 2 points of territory for white = +2).

If W1 at B1 instead, the score is -5. (4 points of territory + 1 prisoner)

The deiri value is the difference between these two results, or 7 points.

We may define deiri values as the difference between the count of the first stable position after Black plays first (called a Black follower) and that of the first stable White follower, assuming normally correct play.

A stable follower is one that is cooler than the original position. There is a potential circularity here, but a line of play eventually ends, as here, in a scorable position, or in a repetition, which is prohibited by the rules. (If it is not, the original position does not really have a value.)

--BillSpight


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This is a copy of the living page "Deiri Counting" at Sensei's Library.
(OC) 2005 the Authors, published under the OpenContent License V1.0.
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