Nakade

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Re: Nakade

Post by billywoods »

RobertJasiek wrote:1) to apply it as a player

2) to apply it for teaching

But concretely, how? Can you give me an example of a case that this formal definition has helped you understand, for example? Obviously, if I saw how you were managing to apply these things, I would count it as useful research, or at least research interesting in its own right. If you're just writing down abstract definitions with no clear goal for what to do with them, I'm not convinced that it's useful.
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Re: Nakade

Post by RobertJasiek »

The definition clarifies:

Click Here To Show Diagram Code
[go]$$B The marked region is a nakade
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O B O O . X
$$ | X X . C B B O . .
$$ | X . O O B C . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


As I notice now, the definition fails here, because,

Click Here To Show Diagram Code
[go]$$B The marked region should be a nakade
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O B O O . X
$$ | X X X . B B O . .
$$ | X . O O B O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


if the defender is assumed to occupy the adjacent intersections,

Click Here To Show Diagram Code
[go]$$B Occupying adjacent intersection
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O . O O . X
$$ | X X X O . . O . .
$$ | X . O O . O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


the inside string has lost its liberties and is removed. Now, according to the definition (second bullet point), the defender moves first

Click Here To Show Diagram Code
[go]$$W Partitioning play
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O . O O . X
$$ | X X X O 1 . O . .
$$ | X . O O . O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


and partitions the region into at least two regions.

Click Here To Show Diagram Code
[go]$$B Defender moves second
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O C O O . X
$$ | X X X O C C O . .
$$ | X . O O C O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


If we alter the definition and, in the second bullet point, let the defender move second, the region is identified as a nakade,

Click Here To Show Diagram Code
[go]$$B The marked region is a nakade
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O . O O . X
$$ | X X X O 1 . O . .
$$ | X . O O . O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


because White cannot partition it, but this is wrong; an unstable eye is not a nakade shape yet, but a shape in which the attacker's first move can create a nakade shape.

Now how to alter the definition? Require alternate play for the adjacent intersections and allow play also on them? Two or three cases, one for an already surrounded region, one for a not yet surrounded region with / without inside removals?

EDITED
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Re: Nakade

Post by RobertJasiek »

Draft 2:

A _nakade_ is a region of connected intersections so that

* if the players play only within the region and on its adjacent intersections, the defender moving first can necessarily fill all but one of the intersections of the region,

* if the players play only within the region and on its adjacent intersections, the defender moving first cannot necessarily permanently partition it into at least two regions and surround them,

* if the initial position is the starting position, the players may play anywhere and either player tries to prevent the other's new independent life, neither player can force occurrence of a seki or ko ban involving the region, and

* if each intersection adjacent to the region is occupied by the defender's stone without any outside liberty, the players play only within the region, and either player tries to prevent the other's new independent life, neither player can force occurrence of a seki or ko ban involving the region.

The second bullet point applied:

Click Here To Show Diagram Code
[go]$$W Example 1
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O B O O . X
$$ | X X . C B B O . .
$$ | X . O O B C . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


Click Here To Show Diagram Code
[go]$$W Example 1 typical variation
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O X O O . X
$$ | X X . 1 4 X O . .
$$ | X . O O X 3 2 X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


White cannot partition, so it is a nakade.

Click Here To Show Diagram Code
[go]$$W Example 2
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O B O O . X
$$ | X X X . B B O . .
$$ | X . O O B O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


Click Here To Show Diagram Code
[go]$$W Example 2
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O X O O . X
$$ | X X X 1 2 X O . .
$$ | X . O O X O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


White cannot partition, so it is a nakade.

Click Here To Show Diagram Code
[go]$$W Example 3
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O C O O . X
$$ | X X X O C C O . .
$$ | X . O O C O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


Click Here To Show Diagram Code
[go]$$W Example 3
$$ ------------------
$$ | . O X X X X X X .
$$ | O O . . . . . . .
$$ | X . O . O O . X .
$$ | . X O O . O O . X
$$ | X X X O 1 . O . .
$$ | X . O O . O . X .
$$ | X . . . O O . X .
$$ | X . X . . . X . .
$$ | . . . X X . . . .[/go]


White can partition and surround three parts in the initial region, so it is not a nakade, as it should be.

Draft 2 of the definition seems to make progress.

EDIT:

The next question I am having is whether "play only within the region and on its adjacent intersections" is necessary or bad in the second bullet point.
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Re: Nakade

Post by RobertJasiek »

Click Here To Show Diagram Code
[go]$$W Example 4
$$ ------------------
$$ | O O . X O . . . .
$$ | O O . X O . . . .
$$ | X X X X O . . . .
$$ | O O O O O . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


Now I recall why, if the first bullet point is needed at all, it needs its further semeai-eye condition "and do not remove any surrounding stone":

Draft 3 (first bullet point):

* if the players play only within the region and on its adjacent intersections and do not remove any surrounding stone, the defender moving first can necessarily fill all but one of the intersections of the region

Click Here To Show Diagram Code
[go]$$B 2 = pass prescribed by the definition
$$ ------------------
$$ | O O 3 X O . . . .
$$ | O O 1 X O . . . .
$$ | X X X X O . . . .
$$ | O O O O O . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]
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Re: Nakade

Post by cyclops »

A black cy3_nakade_ is a set of connected intersections, empty or occupied, surrounded by black stones such that ....
.. A white cy3_nakade is defined mutatis mutandis likewise.


can necessarily???

I can necessarily be confused by your idiom. No idea what you mean apart maybe from the existence of a valid ( unrefutable ) strategy to achieve something.
How would you translate "can necessarily" into German? "Kann unbedingt"?
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Re: Nakade

Post by RobertJasiek »

Derive necessarily from force in the Japanese 2003 Rules v35a or in one of the ko definition papers. "set of intersection": sure, if you want to avoid informal use of "region".
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Re: Nakade

Post by billywoods »

cyclops wrote:How would you translate "can necessarily" into German? "Kann unbedingt"?

I presume Robert means what most people would mean informally by "can unconditionally".
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Re: Nakade

Post by RobertJasiek »

Force is not about being unconditional, but involves the opponent's resistance.
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Re: Nakade

Post by wineandgolover »

Funny, I feel that I understand the Japanese go-terms better than I do the English interpretations being thrown around in this thread. :scratch:
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Re: Nakade

Post by RobertJasiek »

Maybe you imagine one string surrounding a space with exactly one obvious vital point and being surrounded by opposing stones? This is the simple case. However, there is a much greater variety of shapes, even if you think in Japanese language:)
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Re: Nakade

Post by Cassandra »

RobertJasiek wrote:Maybe you imagine one string surrounding a space with exactly one obvious vital point and being surrounded by opposing stones? This is the simple case. However, there is a much greater variety of shapes, even if you think in Japanese language:)

But then it would be very advisable to choose another term.

"Nakade" is strongly connected with the property of being a vital point for eye shape.

If a group has another eye elsewhere already, as in some of your examples, "Nakade" loses its entire meaning.
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Re: Nakade

Post by RobertJasiek »

Cassandra wrote:But then it would be very advisable to choose another term.


Also eyespace has a great variety of meanings. Rather than introducing new terms, one can identify varieties by denoting the types, as in nakade-(type-)1, nakade-(type-)2.

"Nakade" is strongly connected with the property of being a vital point for eye shape.


No. Rather a few types / uses of the word are, while other types / uses are not. In particular, there is also the use "no vital point" (because it is occupied by a stone of one of the attacker's strings or because the shape does not have any vital point, such as an empty block of four).

If a group has another eye elsewhere already, as in some of your examples, "Nakade" loses its entire meaning.


It does not lose its meaning. Quite contrarily, it still exists in a richer context! E.g., "A group with two separate nakade eyes can be killed by a ko threat and its follow-up cutting the group and its eyes apart."

*************************************************************

Click Here To Show Diagram Code
[go]$$B necessary fill condition
$$ ------------------
$$ | C W W X . . . . .
$$ | W C W X . . . . .
$$ | W W X X . . . . .
$$ | X X X . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


The "fill" condition is necessary so that an opponent's independently live formation is not confused with a nakade. (Black cannot almost-fill and cannot partition the marked region.)

Click Here To Show Diagram Code
[go]$$B necessary cannot partition condition
$$ ------------------
$$ | X C C C X . . . .
$$ | X C X C X . . . .
$$ | X X X X X . . . .
$$ | . . . , . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


The "cannot partition" condition is necessary so that a connected part of an eyespace providing at least two eyes is not mistakenly identified as a nakade. (Black can almost-fill and can partition the marked region.)

EDIT: corrections
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Re: Nakade

Post by daal »

Robert, is there a significant difference between:

...the defender moving first can necessarily fill all but one of the intersections of the region...

and

...the defender moving first can fill all but one of the intersections of the region...?

If so, what is it?
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Re: Nakade

Post by RobertJasiek »

daal wrote:...the defender moving first can fill all but one of the intersections of the region...?


Anyway, what must be expressed or implied is that the players alternate and the opponent resists (tries to oppose) the defender's aim. "can" is too weak, because it could mean "let the defender play successive moves". "necessarily" is a gentle reminder that it is not the dullest meaning of "can"; maybe too gentle:) If you think so, write "force", or even explain it or at least its implications (opponent's opposite aim, per turn at least one move fulfilling a purpose versus none / all) in a commentary for such definitions.

Defender's aim: almost-fill.
Attacker's aim: prevent the defender from almost-filling.
The opposite of either aim is the other's aim.
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Re: Nakade

Post by Bantari »

RobertJasiek wrote:The value of research, building on top of prior work, cataloguing, pushing the overall knowledge a step further has a tremendous value not only for the theorists, but also for practical applications. Maybe not always immediately, but surely later. It is the general effect of fundamental research. This is so also for a careful definition of nakade.


This sounds right in principle, but has it been actually demonstrated in the field in question? This is part of my unease about the value of what you do. As you can say is that generally speaking, formal research is a good thing. But what if Go is different, what if in Go formal research does not bring much fruit?

I base that uncertainty mainly on two points:

Point #1:
After all this time, it is absolutely not clear to me what practical value is there in all this. Can I get stronger by reading a formal definition of 'nakade'? You keep saying 'eventually', but it seems 'eventually' never comes... Or if it does, it comes too slow for me to notice. You're at it for what? 20 years? 30? 40? When do you expect to see measurable practical results due to all this research? In general.

Point #2:
The fact that I look at other similar fields. For example: chess. I know a lot of formal research has been done in chess, especially in the old Soviet Union, tremendous amounts of money have been spent, and yet it did not seem to have contributed very much. From what I understand, the high level of play in SU was due mostly to incentives and refining traditional methods, not formal theoretical research. They had tons of paid researchers, formal institutes, and what not. But after all this huge effort spanning decades and backed up by resources of a whole country, it seems that the best and fastest way to learn chess is still the old-fashioned way of rote memorization, examples, tactical problem solving, and simply experience.

I mean - I know you are having fun, but is this research only for the sake of research, or to appease some personal itch you have?

RobertJasiek wrote:Aims of nakade definition research: I am doing this research, because I am in urgent need for its application when teaching life and death more profoundly than by only repeating known standard examples.


I seriously hope you are not going to roll out your formal definitions when teaching.... No offense.
But that's beside the point here.

RobertJasiek wrote:Traditional methods: why. There has been (almost) only one method: teaching by examples:) Even you will admit that more methods can be better than only one method. Careful definitions are a means to then develop more methods.


Can I really admit that? Again - this is something that "in general" sounds good, but is it true in this case? What if the traditional method is the best and most efficient? What do we gain by putting so much effort ad resources into developing alternate methods. Maybe if you put all this effort into studying Go the traditional way, you would have been a top pro by now? We will simply never know...

Look at the chess example I gave above.

True, you might say we never know until we try, and you are right. But then the best we can say is: lets try and see how it goes. We cannot say: what we do is extremely valuable and/or important. We simply do not know... yet. Indications seem to go both ways, depending which field of study you look at.

So, back to your statement of me admitting that more methods is better than one. Yes, I can. If we have a cheap choice, if a new method or a bunch of new methods is handed to us, I would say - sure, take it. We lose nothing, even if these methods are not very good or very practical. However - this is not the case here, we are faced with a lot of effort to derive at these new methods (true, not my effort, but still effort) - so in principle, some kind of cost-to-reward analysis would be interesting.

Well - its all moot anyways, because I suspect you are simply having a lot of fun doing all that, and you would do it even if it could be proven that it will never have much practical use. More power to you, I have no problem with that. What I question is you repeatedly stressing how important and valuable it is what you do. I am not saying you are wrong, I am just saying this has not be demonstrated yet.
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