It's playable for black if black has stones in the bottom right. Otherwise, white has too much influence.

I've used this a lot in games. When white's influence/thickness isn't too much and white takes gote, I'm happy. At my level, white sometimes tenuki, and you have to punish it:

Click Here To Show Diagram Code

[go]$$c (White tenukis)
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . X 5 . |
$$ | . . . . . . . . . . . . . . . O O 3 . |
$$ | . . . . . . . . . . . . . . . . . 4 . |
$$ | . . . . . . . . . . . . . . . 2 1 . . |
$$ | . . . . . . . . . . . . . . . 7 . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Anyway, it doesn't really matter what other people think about the position regarding if it's joseki or not.

How do you feel about it? Just keep it in your pocket as a possible option during your games, and when you think the resulting situation will be good for you, pull it out.

_________________
be immersed

Half the pro games in my database where this appears, White tenukis after 5 with no special advantage to either side. There is no example of 7. After White cuts, how does Black 'punish' White?

_________________
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

You can play S12 then, and white is split.

You don't have to do it immediately, but since this exists, white didn't get much of a position locally compared to if he takes gote in the "joseki". Of course, it depends on the rest of the board.

In some board positions, it may well be better for white to tenuki. And in some board positions, it may not be good for black to select this line of play in the first place. But that's the same with anything.

Locally, though, I think black 7 above is often a good followup for black to split white up.

_________________
be immersed

You cannot "presume that both players have strived to create good shapes". Some variations get avoided because of shape issues. One of the simplified variations of the taisha joseki is usually not played because it gives black better shape. See below.

Click Here To Show Diagram Code

[go]$$c joseki
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . , . . . . . , . . . . . , 2 . . |
$$ | . . . . . . . . . . . . . . . 3 4 . . |
$$ | . . . . . . . . . . . . . . . 5 . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Click Here To Show Diagram Code

[go]$$c joseki?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . , . . . . . , . . . . . , 2 . . |
$$ | . . . . . . . . . . . . . . 5 . 4 . . |
$$ | . . . . . . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

But as I understand, your method will give the same number to both.



Okay now I understand what you are doing. Still, I believe you should have more justification than simply that 399 of 400 joseki positions suggested by pros fit to your formula. There's also some chicken and egg problem here since you're assuming the pros have made a correct decision to file out locally optimal exchanges as 'josekis'. You haven't yet explained what makes up a joseki, what comes before a sequence of locally optimal plays is completed.

I very often think about playing this variation but have played it out few times. The diagonal attachment starting this joseki is often called a bad move. But the end result do seem playable for both. I found 36 pro games starting with the invasion in the middle, so professional players seem to think at least this is playable. I found this variation in a book which is a dictionary of new josekis, and I was very surprised when the author Kim Seongrae 8p named this as '정석 (joseki)'. I have had many thoughts about this position, so I happened to ask for people's opinion.

MinjaeKim, I have provided more justification elsewhere. "Chicken and egg": I have used pro input for the initial calibration of the ratio range; now afterwards, my method stands on its own. The method provides a joseki evaluation, but you are right that this evaluation alone is not a definition of what is a joseki and everybody is right that a local joseki evaluation does not clarify whether a variation fits a global strategic context. Reading and strategic planning remain necessary.

However, for josekis in their model discussion, there is no such thing as "a sequence of locally optimal plays" because "optimum" must be dynamic and allow a set of possible aims to choose from. For different possible strategic aims, different sequences can be locally optimal. What you can do is to assign every joseki-like variation a superset of set of aims for which it can be good in at least some global contexts.

Kirby, it is not only the amount of generated influence you are interested in but the amount of influence that can be used well.

oren, maybe not everybody speaks of a joseki, but maybe some would call such a sequence a joseki-like follow-up sequence:)

Yes, I agree. Maybe it wasn't clear from my post, since I didn't explicitly state it like this.

That's why I think this is okay for black when white doesn't have a position in other parts of the board (e.g. bottom right) where white's resulting influence can be used well.

_________________
be immersed

It would maybe be clearer not to use a term like "joseki", which is anyway ambiguous. If one speaks of say "dictionary joseki" one gets more context. Before the go database, there were not only small (one or two hundred) and large (up to 5000 and more) collections made of corner sequences; and typically standardised judgements attached (for that time, country, and implicitly editorial policy).

I recently bought a modern Japanese joseki dictionary, and opening it at a random page the judgements on three diagrams are "joseki", "former pattern" and (I think) "unclear" as a continuation of that former pattern. A big part of amateur appreciation and improvement is reverse engineering of pro judgements. So, we should want to know at least what judgement is involved in the verdict "joseki".

It is also true that judgements made on corner patterns without context (i.e. sub-board judgements) are of only a limited value. Another part of amateur appreciation and improvement is reverse engineering of "joseki choice". And another part, I have to say, is "looking at sides as a unit", which I made much of on Sensei's Library a dozen years ago, when the go databases started to kick in.

Still, Robert's data mining seems to be much to do with "dictionary joseki", and this is the sort of area that SFKs might well find useful, as a pedagogic point. Go is a global game, and therefore there is no such thing as "a sequence of locally optimal plays" is a sort of knockdown argument for anything at all. But I don't think it should be used that way. It is properly used as a caveat. (As for example if you are discussing the endgame, and have to say "unless ko threats are important".)

What I think would help me (or at least my knowledge of Japanese, and Korean because the big joseki dictionary I have is a Korean edition) is to shade what Robert has done with some other of the stock judgements that resemble shorthand descriptions.

As for the sequence originally posted, I would classify it as "joseki" in the sense of set pattern, and also in the sense of "shape-fixing pattern" (an underestimated concept). But not as "dictionary joseki" for at least a couple of reasons (as has been said, the sample of sequences is sparse, and also it is a follow-up sequence).

It is more than reverse-engineering: it also involves invention of previously not described theory.

True, and as I understand you, this is wht White 4 is counted as "influence" stone in your calculations.

But cannot the same be said for some of the Black stones, most notably Black Q16? I would say it has a big influence on the Black thickness and on the effectiveness of the other Black stones, not to mention on the number of territory points. So should it not also be counted as "influence stone" for Black?

And if not, where is the line separating such "stones important for thickness greatly" from stones which are important for thickness but not quite that greatly?

_________________
- Bantari
______________________________________________
WARNING: This post might contain Opinions!!

1) The other black corner stones have the major purpose of protecting territory.

2) Their outside influence is dominated by the outer black influence stone and the white influence stones.

3) Therefore they are not significant as outside influence stones.

Sorry to harp on this like that, but I honestly do not see a difference in this respect between, say, White 4 or 6 and Black Q16. None of these stones exert direct influence, but all of them certainly contribute to the stones which do excert influence (and the overall structure) to be stronger. So if White 4 and 6 are counted, why not Black Q16? Is that because, as you say, it secures territory and therefore cannot be counted towards influence? But can't a stone fulfill two functions equally well?

From what you say, this is what I understand:
Black Q16 has the major purpose to secure territory, and the influence is dominated by Black O17 anyways, thus Q16 is not counted.
White 4 has the major purpose to make the White group strong, and in spite of influence being dominated by other White stones, White 4 is counted.

So the main difference is that Black Q16 secures territory while also strengthening the group, and White 4 strengthens the group while also securing territory (although less than Q16).

So where is the line that separates what you count and what you do not count as "influence stone"? Is it "more territory" vs "more strength? Or "mostly territory" vs "mostly strength"?

Or is there another metric, which you did not provide, which makes the support stone on White 4 count as "influence stone" while Black support stone at Q16 not count?
__________
PS>
As a matter of fact, from my intuitive perspective, I would see that Black Q16 does exert some small measure of influence, while White 4 does not. Both stones strengthen the groups they belong to. What's more - again, from my intuitive perspective - I would say that White group exerts exactly the same influence with or without White 4, while Black's influence is slightly lower without Black Q16.

In my intuitive approach, White 4 contributes not to what I would call "influence" but to "strength" - as in "projecting strength" - by making the White group stronger. The concepts are related, but not the same. I am not sure if this is also part of your theory, but I found such distinction useful in the past - between "influence" and "projecting strength", and how the stones contribute to each of those concepts.

In my mind, if you assume that White 4 contributes directly to influence, then is that safe to assume that you consider those two concepts one and the same? Or do you make other distinctions which I do not see here? Or are these concepts in this form meaningless to you and your theory?

_________________
- Bantari
______________________________________________
WARNING: This post might contain Opinions!!

A stone can fulfil multiple functions but, for the concept of influence stones, I define them to be counted only if outside influence rather than inside territory is their major purpose.

It helps you to recall how (active) influence is generated: as degrees of connection, life and potential for making additional terriory later.

The influence of one particular white stone is not dominated by the influence of the other white stones, but each white stone is essential for constituting the white group of thickness with its effect of generating influence.

You ask for a line exactly where influence stones are distinguished from non-influence stones, i.e., a set of criteria exactly which are versus are not fulfilled in combination. I cannot provide this exactness of algorithmic quality. All I have is ca. a dozen principles with which the distinction can be made in most practical cases.

The stone White 4 on the board or not makes this difference to the white group: without the stone, the white group does not have two eyes and can be attacked. With the stone, the white group has two eyes and (apart from minor aji) cannot be attacked. This difference has a great impact on the degrees of influence the white group represents on the outside.

I have defined thickness and I have defined influence. Simply speaking, thickness (or, in a weaker form, "a group of influence [generating] stones") is the property of stones. Influence is the property of other intersections affected by such stones.

http://senseis.xmp.net/?Thickness
http://senseis.xmp.net/?Influence

Could you teach this to others to a level that they can apply it and reach the same verdicts as you on novel positions, or have you?

_________________
Occupy Babel!

Answer: viewtopic.php?f=17&t=12402

Well, for this kind of thing, and in particular for the claim that your interpretation/theory goes beyond standard ideas of strong player, the difference between esoteric and exoteric is key. In other words something teachable is what is wanted.

Something teachable is nice, of course.

Do the standard ideas of strong players offer anything teachable that relates stone difference, territory and influence so that two different, abitrary corner positions can be compared? It is rare that the stone difference and amount of territory are mentioned at all. What is not even mentioned cannot be related to influence. If a degree of (source of) influence is stated at all, it almost always is very rough, as in "the group is thickness". One cannot decide which position has the stronger group if each is called (e.g. ordinary) "thickness" indifferently. Without measuring group strength or influence, they cannot be related well to stone difference and territory.

Even if your assessment of influence stone difference is imprecise (because so far I have taught it only as "significant" and by ca. 500 value-asssigned examples), it IS a measurement of influence at least. This is much more useful, quickly applicable, accurate and teachable than anything I have seen from professionals or other amateurs. Of course, you can and should criticise me for not having provided a mathematical definition of 'influence stone' (and the mentioned principles also do not offer it yet - and I have not solved the game...) but you should also recognise that what I offer has a much greater precision than what the "strong players" offer.

Achieving teachability does not have to mean dumbing down. The Japanese, for example, have covered Robert's elements in ways that demand a little more from the reader. I'm from a generation that was used to that way of being taught and it was sometimes frustrating, but I'm still inclined to believe it's the best way.

It's interesting to compare the approaches in some detail for the present case. The elements Robert seems to emphasise most in the current context are stone count, influence stones, current territory, and he restricts his domain mostly to josekis. Let us look at the different approaches.

Stone difference
In his dictionary, Robert specifically mentions the difference in number of White and Black stones in each position. The Japanese only very occasionally do this, rather more often hint at it (e.g. by saying one side gets sente can tenuki), but usually assume the reader can and will count. Of course some of us are too lazy to count...

Current territory
The Japanese call this 確定地 - settled or confirmed territory, and define it in terms such as "points a player can expect to belong to his own final territory." Here is a very simple example from O Rissei, but this concept is in very widespread use in Japan.



I think Robert would demarcate the same area but as I understand it he would say White's current territory is 12 points. O Rissei puts it at "a little above 10 points". This vaguer way of expressing it is typical in Japan. It could be argued it's a cultural thing, as people go out of their way in ordinary conversation to avoid directness, but since the verdicts on confirmed territory are very often accompanied by phrases such as "Black is slightly thicker overall" I think it is safe to assume that the go usage is merely expressing a pro's feeling for future probabilities. It's probably also a matter of personal taste as to whether you prefer more precise numbers are whether you regard precision in such cases as spurious (noto to the mention the important difference between precision and accuracy).

Influence stones
For grammatical and reasons the Japanese are disinclined to use such terms themselves (e.g. singular and plural are not distinguished and 'stone' can also mean 'group'). The term they use in this case is atsumi, which is often rendered as 'thickness' in English, but that loses the important contrast with atsusa, which is also usually rendered as 'thickness'. However, diagrams take most of the burden and here is an example that shows a couple of the problems Robert likewise faced in the "joseki" above.



Sticking with Robert's term for convenience, O Rissei says the triangled stones are 'influence stones' but the squared stone is not (the reason being that: "If it can be cut off it cannot be deemed strong, and so it is not [atsumi] thickness").

I don't think many of us would have any problem with that particular point, but of more interest here is the situation with the white stone on C16. This does not face the outside but if we look at reasons why it might be counted as an influence stone (Charles's 'reverse engineering', perhaps) we might deduce that it helps with a potential squeeze against Black's pyramid hat group, which would extend White's influence.

A more prosaic hypothesis might be that it's solidly connected to the other stones designated as influence stones. But that's unlikely. For one thing, O also gives the following position:



The stone on R4 is not counted as an influence stone (triangled).

Going back to the previous diagram, the connected-stone hypothesis would mean that if White adds a stone at 'A' he would be adding two influence stones. Actually, Abe Yoshiteru discusses this point in his book on how to count thickness. He says that stones on the second line are not usually counted as part of a thickness wall, but can be in some situations (he gives examples). We see an example also from O Rissei, in the position above (Q2).

Abe and O talk about influence stones for reasons somewhat different from Robert's. O is talking about the "pitfalls of thickness [te-atsusa]" and his more general topic is atsumi thickness and moyos. Abe is using walls as a way of counting thickness (the formula is n * n-1 / 2 where n is the number of discrete stones in the wall, usually on the third line up, but the wall can also bend round). There are other aspects of go covered by other people writing in similar vein. The aspect that interests Robert, josekis, is usually covered in joseki books - obviously - but most often in sections/books/articles on tewari. But where numbers are used, e.g. to compare thickness vs territory in a joseki, it is again the case that the Japanese will reduce these to "about n", "a little over n," etc. One reason for delegating the 'theory' part to tewari discussions and the like is that the Japanese approach is most often to reach techniques that are applicable to all phases of the game. Again it is a matter of taste whether you try to build your Lego model by following the instruction book or by just looking at the picture on the box.

Thank you for throwing some light on Japanese pro contibutions! Which are the sources (books)?

I do not restrict the concepts to joseki study, but, when I speak of my joseki evaluation method, it applies only to joseki-related study. The concepts are very useful also for other purposes.

I agree that professionals are aware of stone difference and expect (too much) of every amateur to determine it without saying. It is nice to hear that Cho Chikun has not been the only Japanese pro to consider settled / confirmed / current territory, but I wonder how clearly aware they are of a maintained sente condition.

Being imprecise about numbers of points etc. can be excused in verbal talk. In writing, it shows a lack of courage for the fear of being criticised for possibly stating an amount of territory that is 1 point off from others' consensus. It is (attempted) precision that has enabled me to find my joseki evaluation method at all, because I noticed consistent value relations at all when writing down the values for hundreds of example positions.

I agree with O's markings of influence stones, except where his different purpose of application lets him make a distinction about a stone that can be cut. In particular, a stone behind the outside front line but contributing much to eyespace of thick shape must be counted. I am glad that O gets this right. (EDIT: due to different application purpose, I would nevertheless count differently, when such a stone has the major purpose of making territory.) Also it is right not to count every string-connected stone.

IMO, the Japanese pro emphasis of tewari has historic reasons: it is an old Japanese concept having some useful applications. My mind is more detached from traditional impact of earlier go theory:)

O seems to study something different here: 'thickness-constituting stones' rather than 'influence stones'. The three inner white triangled stones have several purposes: protect territory, protect eyespace, contribute to forming thick shape, contribute to forming thickness, increase the value of outside influence by increasing the life and (less so) connection degrees of the thick shape / thickness stones. The three inner white triangled stones are thickness-constituting but, as potentially counted influence stones, are dominated by the outer triangled stones. Therefore, I do not count the inner triangled stones as significant outside influence stones. I count the three outer triangled and the squared stones as significant outside influence stones.

The maybe more interesting question is: why don't I count any black stones as influence stones? White has the forcing exchange F17 - E18, after which none of the black stones is on the outside (and F17 itself is too weak to count as a significant influence stone).

Note that the cut is White's disadvantage compensating is advantageous values.