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 Post subject: The six point rule
Post #1 Posted: Sat Feb 10, 2024 11:42 pm 
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Anyone heard of the six point rule?

The six point rule (6目ルール) is that surrounding 6 points will usually secures life.

Let's first apply the rule to two groups to see how it works.

Click Here To Show Diagram Code
[go]$$B Shape
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X . . . .
$$ | . O X . . . .
$$ | . O O X . . .
$$ | . . O X . X .
$$ | . . O O X . .
$$ | . . . . . . .
$$ +--------------[/go]


In this shape it looks like white has surrounded 6 points. If we are naive about it then we would reach a dead shape, see the next diagram, though it could be possible to escape :scratch: However, with a better defense, seen in the next-next diagram, it is clear that white does survive and indeed has 6 points.

I'd say that the rule predicts that white is alive based on the more naive variation. That is white is surrounding 6 points on the face of it. It is a useful visual guide for spotting tsumego in your own games but you need to be very careful.

Click Here To Show Diagram Code
[go]$$B Shape has six points (on the face of it)
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X . . . .
$$ | 3 O X . . . .
$$ | 4 O O X . . .
$$ | . . O X . X .
$$ | . . O O X . .
$$ | . . 2 1 . . .
$$ +--------------[/go]


Click Here To Show Diagram Code
[go]$$B Shape is alive
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X . . . .
$$ | . O X . . . .
$$ | . O O X . . .
$$ | . . O X . X .
$$ | 2 . O O X . .
$$ | . . . 1 . . .
$$ +--------------[/go]


Now, here is a shape where white does not have six points. White could be said to have 5 points, on the face of it. This shape is therefore predicted to be dead if black attacks.
Click Here To Show Diagram Code
[go]$$B Shape
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X X . . .
$$ | . O O X . . .
$$ | . . O X . X .
$$ | . . O O X . .
$$ | . . . . . . .
$$ +--------------[/go]


Click Here To Show Diagram Code
[go]$$B Shape has 5 points
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X X . . .
$$ | 1 O O X . . .
$$ | 2 . O X . X .
$$ | . . O O X . .
$$ | . . 4 3 . . .
$$ +--------------[/go]


Click Here To Show Diagram Code
[go]$$B Shape is dead (You just have to believe me)
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . 3 . . . . .
$$ | 2 X X X . . .
$$ | 8 O O X . . .
$$ | . 9 O X . X .
$$ | 4 7 O O X . .
$$ | . 5 6 1 0 . .
$$ +--------------[/go]


Here are some shapes that are alive, have six points and I shamelessly lifted from the linked youtube video.

Click Here To Show Diagram Code
[go]$$B
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . X O . . O X . . . . X O O X X . .|
$$ | . . X . O . O X X X X X X O O . . . .|
$$ | . . . , O . . O O O O O O . . O X X .|
$$ | . X X X O . . . . . . . . . . . O X .|
$$ | . O O O . . . . . . . . . . . . O O .|
$$ | . . . . . . . O O O O O . . . . . O .|
$$ | . . O . . . O . X X X . O . . O O X .|
$$ | . O . . . . O X . . . X O . O X X X .|
$$ | . X O O . . O X . , . X O . O X . . .|
$$ | . X X X O . O . X X . X O . O X . . .|
$$ | . . . X O . . O O X . O . . O X X X .|
$$ | . . X O . . . . . O O . . . . O O X .|
$$ | . . X O . . . . . . . . . . . . . O .|
$$ | . X X O . . . . . . . . . . O O . O .|
$$ | . O O , O O O O O , . . . O . , O O .|
$$ | . . O O X X X X X O O . . O X X X X .|
$$ | . . O X X . . . X X O . . O X . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]


Is this one of those ancient sage wisdoms that no one has heard of? Are there any other similar rules? I can't seem to think of any.

I think I recall hearing about it long time ago. Something passed on by a friendly Japanese man to the local Go club. I might not remember that correctly, I didn't believe in such rules back then :lol:

Now I heard about it (again?) from the Shibanos channel.

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 Post subject: Re: The six point rule
Post #2 Posted: Sun Feb 11, 2024 5:08 am 
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kvasir wrote:
Is this one of those ancient sage wisdoms that no one has heard of?


No, it pops up in quite a few books on life and death.


kvasir wrote:
Are there any other similar rules?


Y... Yes? Hundreds? Depending on your definitions of "similar" and "rules", of course.

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 Post subject: Re: The six point rule
Post #3 Posted: Sun Feb 11, 2024 8:33 am 
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kvasir wrote:
Anyone heard of the six point rule?

The six point rule (6目ルール) is that surrounding 6 points will usually secures life.

Let's first apply the rule to two groups to see how it works.

Click Here To Show Diagram Code
[go]$$B Shape
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X . . . .
$$ | . O X . . . .
$$ | . O O X . . .
$$ | . . O X . X .
$$ | . . O O X . .
$$ | . . . . . . .
$$ +--------------[/go]


In this shape it looks like white has surrounded 6 points. If we are naive about it then we would reach a dead shape, see the next diagram, though it could be possible to escape :scratch: However, with a better defense, seen in the next-next diagram, it is clear that white does survive and indeed has 6 points.

I'd say that the rule predicts that white is alive based on the more naive variation. That is white is surrounding 6 points on the face of it. It is a useful visual guide for spotting tsumego in your own games but you need to be very careful.

OC you have to be very careful!

I never heard this rule and it looks to me quite interesting because it works quite well in a great number of cases.

At least I see an obvious exception to this rule with the following dead shape:
Click Here To Show Diagram Code
[go]$$W white to play and kill
$$ . . . . . . . . .
$$ . . O O O O O . .
$$ . O O X X X O O .
$$ . O X X . X X O .
$$ . O X . . . X O .
$$ . O X . . X X O .
$$ . O X X X X O O .
$$ . O O O O O O . .
$$ . . . . . . . . .[/go]

See the following application in the corner
Click Here To Show Diagram Code
[go]$$W white to play and kill
$$ | -------------
$$ | . . . . . . O .
$$ | . . . X O O O .
$$ | . . X X O . . .
$$ | . X X O O . . .
$$ | . O O O . . . .
$$ | . O . . . . . .
$$ | O O . . . . . .
$$ | . . . . . . . .
$$ | . . . . . . .[/go]

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 Post subject: Re: The six point rule
Post #4 Posted: Sun Feb 11, 2024 9:58 am 
Gosei

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The rule I learned is "6-7-8": (in general) a 6-point area in the corner is dead, a 7-point area is unsettled, and an 8-point area is alive. In-seong Hwang has a lecture about it on his Yunguseng Dojang site (not free).

This is off by two from your rule! I guess the difference is that when you do 6-7-8 counting, you don't worry about hanes. So for example in this diagram you count the squares as well as the triangles:

Click Here To Show Diagram Code
[go]$$B 8-point area
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X . . . .
$$ | . O X . . . .
$$ | S O O X . . .
$$ | T T O X . X .
$$ | T T O O X . .
$$ | T T S . . . .
$$ +--------------[/go]

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 Post subject: Re: The six point rule
Post #5 Posted: Sun Feb 11, 2024 10:40 am 
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Akura wrote:
No, it pops up in quite a few books on life and death.


Interesting.

Akura wrote:
Y... Yes? Hundreds? Depending on your definitions of "similar" and "rules", of course.


Please share but one 1% of those great wisdoms!

Gérard TAILLE wrote:
OC you have to be very careful!

I never heard this rule and it looks to me quite interesting because it works quite well in a great number of cases.

At least I see an obvious exception to this rule with the following dead shape:


Definitely. There are smaller shapes that are still alive as well as larger shapes that are completely dead. Everyone has to start somewhere. Many shapes that we think of as easy require recognizing some geometry, even some shapes I'd consider elementary are tricky if you try to brute force them. This rule is fairly simple and could it be said to point to the right direction as to how to learn life and death?

The Shibano that made the presentation on Youtube claimed that in his experience the rule works 80% of the time.

dfan wrote:
The rule I learned is "6-7-8": (in general) a 6-point area in the corner is dead, a 7-point area is unsettled, and an 8-point area is alive. In-seong Hwang has a lecture about it on his Yunguseng Dojang site (not free).


Interesting. Maybe it is an improvement over the 6 point rule but I like that it should be difficult to interpret the 6 point rule a s something exact. 6-7-8 at first sounds like there is some precision to it. I wonder if it is possible to test and compare different rules.

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 Post subject: Re: The six point rule
Post #6 Posted: Sun Feb 11, 2024 11:34 am 
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dfan wrote:
The rule I learned is "6-7-8": (in general) a 6-point area in the corner is dead, a 7-point area is unsettled, and an 8-point area is alive. In-seong Hwang has a lecture about it on his Yunguseng Dojang site (not free).

This is off by two from your rule! I guess the difference is that when you do 6-7-8 counting, you don't worry about hanes. So for example in this diagram you count the squares as well as the triangles:

Click Here To Show Diagram Code
[go]$$B 8-point area
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . X X . . . .
$$ | . O X . . . .
$$ | S O O X . . .
$$ | T T O X . X .
$$ | T T O O X . .
$$ | T T S . . . .
$$ +--------------[/go]

With this example the 6 rule and the 6-7-8 rule gives the same result.
I do not see clearly in which circumstances the 6-7-8 can be applied. It seems to cover positions where two hane exist. If it is true I prefer the simple 6 rule which take into account the hane.

Just a simple example
Click Here To Show Diagram Code
[go]$$B Black to play
$$ ---------------------------
$$ . O . . . S T T S . . . O .
$$ . O O O X X T T T X O O O .
$$ . . . . O X X X X X O . . .
$$ . . . . O O O O O O O . . .
$$ . . . . . . . . . . . . . .[/go]
With the two hane the two rules look equivalent but ...
Click Here To Show Diagram Code
[go]$$B Black to play
$$ ---------------------------
$$ . O . . X T T T S . . . O .
$$ . O O O X X T T T X O O O .
$$ . . . . O X X X X X O . . .
$$ . . . . O O O O O O O . . .
$$ . . . . . . . . . . . . . .[/go]

Click Here To Show Diagram Code
[go]$$B Black to play
$$ ---------------------------
$$ . O . . . S T T T X . . O .
$$ . O O O X X T T T X O O O .
$$ . . . . O X X X X X O . . .
$$ . . . . O O O O O O O . . .
$$ . . . . . . . . . . . . . .[/go]
in the two above positions, with only one hane, the 6 rule is correct where the 6-7-8 rule does not work.

The 6 rule tells us that with 6 points the group is in general alive
Do you have examples for which the 6 rule fails while the 6-7-8 gives the good result?

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 Post subject: Re: The six point rule
Post #7 Posted: Sun Feb 11, 2024 12:33 pm 
Gosei

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Gérard TAILLE wrote:
I do not see clearly in which circumstances the 6-7-8 can be applied. It seems to cover positions where two hane exist. If it is true I prefer the simple 6 rule which take into account the hane.

Well, for example, the L group has 6 points, both L+1 groups have 7, and the L+2 group has 8. So it covers all of those cases nicely. Maybe it really ends up being equivalent to "6 points after hanes is alive" in the end. Today is the first time I encountered this basic "six point rule", so I haven't examined the differences closely yet. I suppose I should watch In-seong's lecture again!

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 Post subject: Re: The six point rule
Post #8 Posted: Sun Feb 11, 2024 12:53 pm 
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I haven’t come across the 6-point rule in an Oriental language in that specific form, but it comes up indirectly quite often in tsumego books whenever Flower Six (James Davies’ rabbity six).

I haven’t come across 6-7-8 in that form but it does seem to align with the way Davies treated the L and groups.

When I saw the title of the thread I was expecting it to be about the Korean heuristic that a moyo can be counted as worth 6 points for each (unopposed) stone in it.

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 Post subject: Re: The six point rule
Post #9 Posted: Sun Feb 11, 2024 1:47 pm 
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dfan wrote:
Gérard TAILLE wrote:
I do not see clearly in which circumstances the 6-7-8 can be applied. It seems to cover positions where two hane exist. If it is true I prefer the simple 6 rule which take into account the hane.

Well, for example, the L group has 6 points, both L+1 groups have 7, and the L+2 group has 8. So it covers all of those cases nicely. Maybe it really ends up being equivalent to "6 points after hanes is alive" in the end. Today is the first time I encountered this basic "six point rule", so I haven't examined the differences closely yet. I suppose I should watch In-seong's lecture again!

Oops there is some misunderstanding because I put on my diagram "black to play" instead of "white to play". Sorry for that.
Click Here To Show Diagram Code
[go]$$B White to play
$$ ---------------------------
$$ . O . . X T T T S . . . O .
$$ . O O O X X T T T X O O O .
$$ . . . . O X X X X X O . . .
$$ . . . . O O O O O O O . . .
$$ . . . . . . . . . . . . . .[/go]

Click Here To Show Diagram Code
[go]$$B White to play
$$ ---------------------------
$$ . O . . . S T T T X . . O .
$$ . O O O X X T T T X O O O .
$$ . . . . O X X X X X O . . .
$$ . . . . O O O O O O O . . .
$$ . . . . . . . . . . . . . .[/go]

In the two above diagrams the 6 rule says that the black group is alive. What is the answer of the 6-7-8 rule?

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 Post subject: Re: The six point rule
Post #10 Posted: Sun Feb 11, 2024 2:01 pm 
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Click Here To Show Diagram Code
[go]$$B White to play
$$ . . . . . . . . . . .
$$ . . . O O O O O . . .
$$ . . O . X X X . O . .
$$ . . O X . . . X O . .
$$ . . O X . , . X O . .
$$ . . O . X X . X O . .
$$ . . . O O X . O . . .
$$ . . . . . O O . . . .
$$ . . . . . . . . . . .[/go]

Taking one of the examples presented by kvasir.
The 6 rule says that the black group is alive. What about the 6-7-8 rule?

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 Post subject: Re: The six point rule
Post #11 Posted: Mon Feb 12, 2024 5:22 am 
Gosei

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If these questions are directed at me, I'm afraid I don't know the answers. My recollection was that it was a general principle and not meant as a hard-and-fast rule. (It may even have only been meant to apply to corners.) I don't use the heuristic myself and watched the lecture a long time ago. I hope I didn't come across as an expert on the subject.

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