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 Post subject: About Capturing Races
Post #1 Posted: Tue Jun 16, 2020 11:30 pm 
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It's about Capturing Races. Do good Go players today rather use the counting method of Richard Hunter from his book "Counting Liberties and Winning Capturing Races", or do they read 10 - 15 moves deep variants each time?
I tend to get used to Richard Hunter's method from the beginning.
What do you think? What´s better?

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 Post subject: Re: About Capturing Races
Post #2 Posted: Wed Jun 17, 2020 12:26 am 
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I don't know how strong players proceed, but in any case some reading to find the correct shape is unavoidable.

Here is a capturing race that both players missed (2k vs. 3k on KGS, I was white), although the problem is not particularly difficult. It shows we are lacking tesuji practice.

White to play and kill the marked stones.

Click Here To Show Diagram Code
[go]$$Wc White to play and kill the marked stones
$$ ---------------------------------------
$$ | . . X X X . . O O . . . . . O X X . . |
$$ | . . O O . X X O X O X O . . O O X . . |
$$ | . . . . O X . X X O X O . . O X . . . |
$$ | . . . O . X X . X O O . . . O , X . . |
$$ | . . . . . . . X O . . . O O X X . . . |
$$ | . . . O . . . X O . . . . X . . . . . |
$$ | . O O O . . X O . . . X . . X . . . . |
$$ | . X X O X . . O . . . . . . . X . . . |
$$ | . . . X . X X . . . . O X X . O X . . |
$$ | . . . X . X O . . , . . O O . O . . . |
$$ | . . . X X . . . O . . . . . . . . . . |
$$ | . . X . . X . X X O . . . . O O O X . |
$$ | . . . . O . . . . . . . O . X O X . X |
$$ | . . O . . O O O . O . O . O X O O X . |
$$ | . . . . . . X X X O . O O X O O X . X |
$$ | . . . O X X . O X O B O . X X X X X . |
$$ | . . . O O X . O O B B . O . O X . . . |
$$ | . . . . . . X . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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Post #3 Posted: Wed Jun 17, 2020 1:42 am 
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Pros read.

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 Post subject: Re: About Capturing Races
Post #4 Posted: Wed Jun 17, 2020 2:32 am 
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Pros read, but they also count. Even if they don't say so.

For instance:

Click Here To Show Diagram Code
[go]$$ Capturing race
$$ . . . . . . . .
$$ . X X X O O O .
$$ . X O O X X O .
$$ . X . O X . O .
$$ . X . O X . O .
$$ . . X O X . O .
$$ . X . O X . O .
$$ . X . O X . O .
$$ . X . O X X O .
$$ . X . O . X O .
$$ ---------------[/go]


Experienced players see that White wins this capturing race, even if Black plays first. But to read it out fully, even assuming we know White's plays, requires reading 720 variations, because Black has a choice among 6 first moves, then 5 moves on her second turn, 4 moves on her third, and so on. OC, because of transpositions, not all of these variations have to be read out to the bitter end. But nobody does that, not even the pros. If it is not obvious to us, we just count the liberties. :)

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Post #5 Posted: Wed Jun 17, 2020 2:34 am 
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EdLee wrote:
Pros read.


They do but they also prune. A pro seeing an L-group ahead will prune it as dead, not read it out to the bitter end. Likewise a pro seeing a "eye vs no eye" capturing race will count the shared liberties for the eye group, rather than reading it out to the last liberty. They probably haven't read Richard Hunter for the purpose. I did and I found it very helpful.


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Post #6 Posted: Wed Jun 17, 2020 2:58 am 
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Knotwilg wrote:
EdLee wrote:
Pros read.


They do but they also prune. A pro seeing an L-group ahead will prune it as dead, not read it out to the bitter end. Likewise a pro seeing a "eye vs no eye" capturing race will count the shared liberties for the eye group, rather than reading it out to the last liberty. They probably haven't read Richard Hunter for the purpose. I did and I found it very helpful.


Pros also learn the number of liberties, in the sense of moves to capture, inside large eyes of certain sizes. Doing so does not make sense if they don't count other liberties. :)

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 Post subject: Re: About Capturing Races
Post #7 Posted: Wed Jun 17, 2020 5:52 am 
Tengen

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Liberty counting is not limited to Hunter's theory but also relies on much more theory by me and others.

Having studied capturing races in actual games during the previous 10 months, half require counting_liberties (because shapes are basic) and half require reading (because shapes are not basic). Among those requiring reading, these percentages occur:


66% only reading

17% reading + counting_liberties

7% reading + techniques

4% reading + counting_liberties + techniques

5% reading + endgame_points


Despite the literature over-emphasising easy-to-write-about techniques (such as related to tesujis), note that only 11% of capturing races with required, hard-to-write-about complex reading are accelerated by applying techniques.


Bill, correct your numbers because pass / play elsewhere is also a move!

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 Post subject: Re: About Capturing Races
Post #8 Posted: Wed Jun 17, 2020 8:31 am 
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On the equivalence of counting and reading

Click Here To Show Diagram Code
[go]$$ Capturing race
$$ . . . . . . . .
$$ . X X X O O O .
$$ . X O O X X O .
$$ . X 1 O X 2 O .
$$ . X 3 O X 4 O .
$$ . . X O X 6 O .
$$ . X 5 O X 8 O .
$$ . X 7 O X 0 O .
$$ . X 9 O X X O .
$$ . X . O . X O .
$$ ---------------[/go]


Playing liberties in a set order makes reading and counting isomorphic. You just, in effect, count one liberty for one player and then one liberty for the other, going back and forth, instead of counting all the liberties for one player and then all the liberties for the other. :)

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At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

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 Post subject: Re: About Capturing Races
Post #9 Posted: Wed Jun 17, 2020 11:43 am 
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Bill Spight wrote:
On the equivalence of counting and reading

Click Here To Show Diagram Code
[go]$$ Capturing race
$$ . . . . . . . .
$$ . X X X O O O .
$$ . X O O X X O .
$$ . X 1 O X 2 O .
$$ . X 3 O X 4 O .
$$ . . X O X 6 O .
$$ . X 5 O X 8 O .
$$ . X 7 O X 0 O .
$$ . X 9 O X X O .
$$ . X . O . X O .
$$ ---------------[/go]


Playing liberties in a set order makes reading and counting isomorphic. You just, in effect, count one liberty for one player and then one liberty for the other, going back and forth, instead of counting all the liberties for one player and then all the liberties for the other. :)


Today I read the first two chapters in Richard Hunter's book (the german version), and now I can see/count/read, in about 10 seconds that white wins the race in the above position. Whether it's his move or not. I couldn't do that this morning after getting up.
And I'm a beginner.
So Richard Hunter must be able to explain very well ;-)


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 Post subject: Re: About Capturing Races
Post #10 Posted: Wed Jun 17, 2020 1:33 pm 
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As to whether counting liberties or reading is better:

1) If counting liberties is applicable to a capturing race as the only needed method, it is faster to very much faster than instead using reading.

2) If reading and counting liberties are applicable to a capturing race as a combination of the two methods, usually the method of reading transforms it to a basic capturing race in some or all variations so that, at their ends, counting liberties is applicable as the only needed method. In such cases, it does not make any sense to call application of either method better than the other.

3) If counting liberties is inapplicable to a capturing race, then the method of reading is not only better but even necessary.

Given my aforementioned statistics, one must be able to apply both (and the less frequently applicable additional) methods well. The more complicated capturing races tend to require (more) reading.

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 Post subject: Re: About Capturing Races
Post #11 Posted: Wed Jun 17, 2020 10:43 pm 
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In chess, where I have almost 2300 Elo, it is a great advantage to get a hint about your prospects in a complicated position. That is why, for example, smartphones are banned in tournament halls. When God tells me: "Matthias, your position is better". Calculate correctly and you will win". Then this is a big advantage, because even top players are never sure during the competition.
So if counting in Go tells me that I should win in a capturing race, then this information alone is an advantage. In this respect I think that this theory should be very valuable.

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 Post subject: Re: About Capturing Races
Post #12 Posted: Wed Jun 17, 2020 11:48 pm 
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Counting liberties, endgame counting and positional judgement (including territory counting and many other aspects) are different things, except especially that determination of status of a capturing race is also part of positional judgement.

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 Post subject: Re: About Capturing Races
Post #13 Posted: Sat Jun 20, 2020 11:53 pm 
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In his book Richard Hunter speaks about "weak eyes". Eyes that have less liberties as it seems, but there is not so much explanation about this. As far as I can see those eyes are mainly in the corner, where its most easy for the attacker of the eye to create a eye within the eye.
Is there any theory about this?
Thanks!

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 Post subject: Re: About Capturing Races
Post #14 Posted: Sun Jun 21, 2020 12:26 am 
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If you think you have weak eyes, a drive to Barnard Castle can help with the diagnosis. </UK politics joke>

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Post #15 Posted: Sun Jun 21, 2020 1:17 am 
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Quote:
If you think you have weak eyes, a drive to Barnard Castle can help with the diagnosis. </UK politics joke>


I was surprised at the time not to see any reference to what that area is really famous for - the geet big goggly eyes of the Lambton Worm. Another sign we are losing touch with our history, perhaps?

Geet big goggly eyes is actually a geet (great) word for nakade shapes, and of course the nakade itself should be a 'hoy in' in English.

The song, of course, begins "One Sunday mornin'" and I read this on a Sunday morning. It's a sign. IT'S A SIGN!!!

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 Post subject: Re: About Capturing Races
Post #16 Posted: Sun Jun 21, 2020 4:07 am 
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jumapari wrote:
In his book Richard Hunter speaks about "weak eyes". [...]
Is there any theory about this?


See https://www.lifein19x19.com/viewtopic.p ... 67#p257667


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 Post subject: Re: About Capturing Races
Post #17 Posted: Mon Jun 22, 2020 8:56 am 
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RobertJasiek wrote:
jumapari wrote:
In his book Richard Hunter speaks about "weak eyes". [...]
Is there any theory about this?


See https://www.lifein19x19.com/viewtopic.p ... 67#p257667

Thank you! Next time I'll read your comments with more attention ;-)

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 Post subject: Re: About Capturing Races
Post #18 Posted: Mon Jun 22, 2020 10:12 am 
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Reading often implies not only the iteration of possible move candidates, but also pruning out branches where the end state is already known. Everybody does this.

One example that comes to mind is a heuristic I heard that says, "in life and death problems, if one side captures 3 stones, they get an eye for that capture". I think this isn't 100% true, but it's true very often. So it means that while I'm doing life and death problems, except for those exceptional cases, I can treat the capture of >= 3 stones as an eye - and I don't have to read out the actual formation of an eye. It speeds things up a little bit, and I can come to recognize exceptions to this rule and revisit as necessary.

Anyway, rules like this help with pruning, which is something that good readers do all of the time - either explicitly or by experience.

But it's important to understand the nuances of things so that when those pruning heuristics aren't applicable, you don't accidentally apply them.

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 Post subject: Re: About Capturing Races
Post #19 Posted: Mon Jun 22, 2020 10:50 am 
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jumapari wrote:
In his book Richard Hunter speaks about "weak eyes". Eyes that have less liberties as it seems, but there is not so much explanation about this. As far as I can see those eyes are mainly in the corner, where its most easy for the attacker of the eye to create a eye within the eye.
Is there any theory about this?
Thanks!


Depends on what you mean by theory. ;) A theory can be a set of facts, i.e., an explicit theory. It can be, and usually is, an implicit theory, i.e, a description of those facts. I think that the explicit theory of weak eyes is complete. That is, every weak eye with the relevant play has been recorded somewhere. As for the implicit theory, what Hunter said is an implicit theory of weak eyes.

BTW, there are eyes that have fewer liberties than they appear to have that are not weak eyes. They are called big eyes. That's not exactly what Hunter said. There is a formula for counting the liberties of big eyes. But there are some big eyes where the formula is wrong. It gives too many liberties. The reason, as Hunter indicates, is that the opponent may make an eye inside the big eye or threaten to do so. Even if correct, that implicit theory is not much help without some of the explicit theory as a guide.

Fortunately, Sensei's Library provides some of the explicit theory on this page. https://senseis.xmp.net/?BigEyesCanBeSmallInTheCorner :)

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The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.


Last edited by Bill Spight on Mon Jun 22, 2020 11:41 am, edited 1 time in total.
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 Post subject: Re: About Capturing Races
Post #20 Posted: Mon Jun 22, 2020 11:37 am 
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Kirby wrote:
Reading often implies not only the iteration of possible move candidates, but also pruning out branches where the end state is already known. Everybody does this.

One example that comes to mind is a heuristic I heard that says, "in life and death problems, if one side captures 3 stones, they get an eye for that capture". I think this isn't 100% true, but it's true very often.


One result of capturing three connected stones.

Click Here To Show Diagram Code
[go]$$W One eye
$$ --------------
$$ . X C C C X .
$$ . O X X X X .
$$ . O O O O X .
$$ . . . . . . .[/go]


Click Here To Show Diagram Code
[go]$$W One eye
$$ --------------
$$ . X 1 2 C X .
$$ . O X X X X .
$$ . O O O O X .
$$ . . . . . . .[/go]

If :w1:, :b2: makes an eye at :ec:.

Another result of capturing three connected stones.

Click Here To Show Diagram Code
[go]$$B No eye
$$ -----------------
$$ . X X C C C X X .
$$ . . O X X X O . .
$$ . . O O O O O . .
$$ . . . . . . . . .[/go]


Click Here To Show Diagram Code
[go]$$B No eye
$$ -----------------
$$ . X X 1 . 2 X X .
$$ . . O X X X O . .
$$ . . O O O O O . .
$$ . . . . . . . . .[/go]

If :b1:, :w2: prevents an eye, except a defective or "false" eye.

(N.B. There are rare cases where the defective eye produced by capturing :w2: will make life.)

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.


Last edited by Bill Spight on Mon Jun 22, 2020 11:45 am, edited 2 times in total.
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