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Miai values list
  Difficulty: Advanced   Keywords: EndGame

Charles: I suggest that we compile a reference list of miai values. These are rational numbers, but I propose we round to two decimal places to keep things relatively clear: 0.005 of a point is really a matter for the experts.

Bill: In practice, 0.5 +/- is good enough precision. E. g., 1.0- is better than 0.5+. There will be times when a tiny fraction of a point will make a difference, but figuring that fraction is not usually easier than reading it out, anyway. ;-)

In fact, as I add plays, I'm starting to feel that 2 decimal points is tedious. Yes, there is a difference between 1.73 and 1.75. But really!

Charles: It gives an ordering. When this list gets spread out over many pages I think this level of detail will look appropriate.

Bill: Bueno, Carlos! :-)

See Miai Values List Discussion for questions and discussion about material on these pages.

Important footnotes: [1][2]

Convention: All examples are framed by empty spaces. There are no alternative plays in the frame, and all stones that are connected to the frame are alive.


Bill: For posters: Please show territory unambiguously. E. g., close it off.

Suggestion 2: If your diagram leaves more play, say how much the next play is worth. That will help the reader look it up. Also indicate the value of any sente followup.


0.00

[Diagram]
Fill neutral point

There are other types of neutral (dame) points including: protective moves (teire) against the cut when outside liberties are filled; capturing stones in seki, etc.



0.33

[Diagram]
Connect ko

[Diagram]
Take ko

HolIgor: This move together with the one above should give a point, shouldn't it?

Bill: Yes, but Black started with 1/3 point net equity in the White stone in atari, so each move gains 1/3 point, on average. :-)

See half-point ko.


[Diagram]
Hidden ko

B3 fills.
1 and 2 are miai points.[3]



[Diagram]
Make ko



[Diagram]
Take ko in sente



[Diagram]
Make ko



0.5

[Diagram]
Take away point

[Diagram]
Defend point

[Diagram]
Take stone

[Diagram]
Jump to take point

[Diagram]
Take away territory

B3 at 1.


[Diagram]
Defend a point

[Diagram]
Take away a point

[Diagram]
Take away point

[Diagram]
Defend point

[Diagram]
Real half-point ko, W komaster



0.58

[Diagram]
Real half-point ko, B komaster



0.67

[Diagram]
Take away point, set up ko capture

[Diagram]
Defend point, set up ko capture

[Diagram]
Take stone to set up ko

Ambiguous.


[Diagram]
Make ko

[Diagram]
Take two stones

[Diagram]
Take away territory (i)

[Diagram]
Take away territory (ii)



0.75

[Diagram]
Take away point (corridor)



0.83

[Diagram]
Defends a point, sets up 0.67 position

[Diagram]
Takes away a point

[Diagram]
Sente

Take stone in sente, leaving 0.67 point play.


[Diagram]
Reverse Sente

Save stone, leaving 0.5 point play.


[Diagram]
Protect, threaten 0.67 play



0.88

[Diagram]
Take away point (corridor)

[Diagram]
One more number

[Diagram]
Take away partial point



0.94

[Diagram]
Take away point (corridor)



For higher values see miai values list - 1.00 to 1.99, miai values list - 2.00 and more.


[1] Territory scoring, naturally; add one for area scoring (see Miai counting - ratio explanation, 'pedantic note about scoring method' for why, and note that points in seki may make a difference as well). Explanations can be added to this page, and annotations (links to other pages, too). The point would be to consolidate a list.

[2] Black to play first (AFAICS we aren't adhering to this Charles): the sequence shown will naturally be Black's sente or ambiguous exactly when White is shown as the last to play. The default for values involving ko is the 'divide by three' miai counting convention. Some values, though, depend on the komaster concept.

Bill: Mea culpa, Charles. If I have just copied a diagram I haven't bothered to change the colors of the stones. Also, when showing both sides of a play, I think it's better to keep the stable stones the same and change who plays first.

[3] Bill, now I'm confused - I think. Black's sente - I've switched the colours for B1, W2. OK, so using miai values means sequences don't need to be flagged as such (sente, or gote). Ah, I get it: White connecting on either side leaves

[Diagram]
Hidden ko (2)



where Black has in effect 0.33.

Leaving this comment for others' benefit. Charles

Bill: This is an ambiguous position. Its miai value is 1/3, but Black can take one stone and threaten to connect with sente. Then, OC, the position still has a miai value of 1/3, and Black's sente has gained nothing locally. (It may have been a ko threat.) In thermographic terms, it has a blue mast up to temperature 1 2/3.



This is a copy of the living page "Miai values list" at Sensei's Library.
(OC) 2003 the Authors, published under the OpenContent License V1.0.