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 Post subject: Re: Japanese books on endgame
Post #21 Posted: Wed Mar 08, 2017 11:52 am 
Honinbo

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Here is an SGF file with four copies of position S. Note that Black, given a choice, should always take the reverse sente instead of the gote.



Moral: When you are evaluating an ambiguous position, assume that it is played as sente. Doing so preserves the original count. :)

----

Remember that I said that ambiguous positions are sometimes treated as sente, sometimes as gote in the go literature? O Meien did both in the space of a few pages, treating Q as sente and S as gote. ;)

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 Post subject: Re: Japanese books on endgame
Post #22 Posted: Wed Mar 08, 2017 4:54 pm 
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Thanks bill, I think I understand now. I only have one question. In both of the examples where white plays first there are two outcomes, white keeps sente and the count is unchanged or black is slightly down and gains sente. My question is, if you account for sente in the value of whites last move is the theoretical count unchanged but white at an advantage by playing the last move on the board?

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 Post subject: Re: Japanese books on endgame
Post #23 Posted: Wed Mar 08, 2017 5:10 pm 
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Razor0310 wrote:
Thanks bill, I think I understand now. I only have one question. In both of the examples where white plays first there are two outcomes, white keeps sente and the count is unchanged or black is slightly down and gains sente. My question is, if you account for sente in the value of whites last move is the theoretical count unchanged but white at an advantage by playing the last move on the board?


Using the method of multiples for gote (where all the followers are also gote) you can always find some number of multiples such that they are strict miai, and it does not matter who goes first, the resulting score is the same. Dividing the result by the number of multiples gives you the count.

But with sente or ambiguous positions the result will depend upon who goes first. As the number of multiples increases, the average of the two results will tend to the theoretical count.

In the SGF files some of the variations are mistakes. When White plays first and Black replies correctly in the S example, Black always gets an average of 12 points. When White plays first in the Q example, with correct play Black always gets an average of 9 - 1/N, where N is the number of multiples.

See http://senseis.xmp.net/?MethodOfMultiples .

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 Post subject: Re: Japanese books on endgame
Post #24 Posted: Wed Mar 08, 2017 6:05 pm 
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Bill Spight wrote:
Razor0310 wrote:
Thanks bill, I think I understand now. I only have one question. In both of the examples where white plays first there are two outcomes, white keeps sente and the count is unchanged or black is slightly down and gains sente. My question is, if you account for sente in the value of whites last move is the theoretical count unchanged but white at an advantage by playing the last move on the board?


Using the method of multiples for gote (where all the followers are also gote) you can always find some number of multiples such that they are strict miai, and it does not matter who goes first, the resulting score is the same. Dividing the result by the number of multiples gives you the count.

But with sente or ambiguous positions the result will depend upon who goes first. As the number of multiples increases, the average of the two results will tend to the theoretical count.

In the SGF files some of the variations are mistakes. When White plays first and Black replies correctly in the S example, Black always gets an average of 12 points. When White plays first in the Q example, with correct play Black always gets an average of 9 - 1/N, where N is the number of multiples.

See http://senseis.xmp.net/?MethodOfMultiples .


Very interesting! I can see your issue with the example. For now I'm just going to be happy knowing how to come up with a count and be aware that ambiguous situations exist. I'm still not totally confident I can find the value of moves properly so I'll try and get my head around that more before I dig into the nitty gritty bits.

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 Post subject: Re: Japanese books on endgame
Post #25 Posted: Wed Mar 08, 2017 6:31 pm 
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Razor0310 wrote:
I'm still not totally confident I can find the value of moves properly so I'll try and get my head around that more before I dig into the nitty gritty bits.


Learning proper evaluation will be a feather in your cap. :)

Bonne chance!

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