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Thickness
  Difficulty: Advanced   Keywords: Strategy, Go term

Thickness = Strength + Influence

Atsumi is a Go-term meaning "the influence of strong stones". We translate it into English with the word thickness. In order to be thick, a group of stones must be strong and it must have influence in a certain direction.

Thickness, strength and influence are often used as synonyms of eachother, hence the discussion mentioned above.

Strength

A strong group is a group with no defects: the stones belonging to the group are connected and have sufficient potential for eyespace. Strength is the local property of a group of stones to stand on its own, the ultimate strength being the group living regardless of what the opponent plays in the neighbourhood.

Influence

Each stone has a certain influence on the board. Captured stones have an influence close to zero. Surrounded stones that make a live group, influence only the surrounding group. Stones that are in open space have an influence on that open space and the stones bordering that open space. Influence is a long range effect. For example: a ladder breaker changes the balance in in the opposite corner.

  • The stronger a group, the greater its influence on a neighbouring area.
  • The more open the neighbouring area, the greater the group's influence.
  • The weaker the other groups neighbouring that area, the larger the group's influence.

In Go, maintaining the balance of territory and thickness is very important.

Examples of thickness

[Diagram]
Diag.: Thickness arising from a sansan invasion

Black has the hoshi stone and the marked stone in place. White approaches with the keima kakari at 1. Black answers with the pincer at 2. White jumps into the corner with 3, and up to 8 the sequence is very common. White has thus taken territory but Black has created a group, consisting of a wall 4-6-hoshi, virtually connected to 2 and 8. The marked stone provides for sufficient space to make eyes for the group. The black configuration is strong and influences the center and the right side.



If the marked stone in the previous diagram is not in place, Black might block the ThreeThreePointInvasion from the other side, in order to create thickness.

[Diagram]
Diag.: Thickness arising from a sansan invasion (2)

Again, Black builds a wall. The marked stone is now closer to the wall, but because a white stone is already in the area, this makes perfect sense. This configuration is again regarded as strong, and influences the center and the lower side.



[Diagram]
Diag.: Thickness arising from a sansan invasion (3)

This is what happens when white immediately makes a ThreeThreePointInvasion. White 7 creates a weakness..


[Diagram]
Diag.:

The White stone is captured in a geta, but some aji remains. White can not run out at A immediately, however. Black is thick.


[Diagram]
Diag.: If white runs out

Black 2 sets up a geta. White 9 is at the marked stone.



Further reading:


Authors: FCS, HolIgor, MortenPahle, AlainWettach, DieterVerhofstadt


This subject was WikiMasterEdit-ed, but has been reopened for discussion --Stefan

This subject has been WikiMasterEdit-ed and re-referenced. The discussion can be found at OldAtsui. Material from OldThickness has been included. --DieterVerhofstadt


--Stefan: Even after the WikiMasterEdit, I feel we should reopen this page for discussion to include the thought provoking thickness concepts currently discussed on rgg. For those who missed the article, it started with this John Fairbairn message on December 9, 2001:

We have had discussions here (meaning rgg - SV) before about what aspects of go exist that the higher-level players know that the rest of us don't. I think it's fair to say our conclusions were dispiritingly fuzzy. In other words, we hadn't a clue and I imagine some of us feel that until Robert Jasiek unveils his long-promised books (this is the real crisis, Robert!) we are destined to remain blissfully ignorant.
However, I have bought a new book today, which seems to promise some relief. Called "A Go Reader for True 5-dans: Playing Thickly" (Jitsuryoku Godan Igo Dokuhon: Atsuku Utsu; Seibundo; ISBN 4-416-70142-X C0076) it is written by the editorial staff of the magazine Igo. There has been a small trend recently for books to be published by such staff in Japan and Korea, and invariably they are much better than the hack books written or ghosted by pros.
This book promises to be the same high quality. It begins thus: "Thickness is a part of thickness," And it tells us that an important skill is to know how to convert thickness into thickness.
This is a classic case of losing something in translation. I'm pretty confident that virtually every instance of go atsumi that has been translated into English as thickness. Ditto every case of atsusa. The opening sentence above actually says atsumi is a part of atsusa.
The adjective is atsui, root atsu-. In Japanese you can make abstract nouns from adjectives by adding -mi or -sa. There is, however, a difference. -sa is more abstract. -mi denotes something rather closer to, but not quite at, a concrete level. Thus, from takai = high, takami can often be translated as high place. Similarly, atsumi suggests to a Japanese structures such as walls, though as this book shows it is wrong to miss out the "such as" (and also quite wrong to think of it as influence).
So the skill we have to learn is to convert atsumi, which I think most dan players more or less understand (the book offers the meaning as something that has no weaknesses), to a more abstract kind of thickness called atsusa.
To help us reach this goal, the book shows examples of atsumi thickness characteristic of several top players. Amazingly different in each case, and I'd wager many people wouldn't even class some as thickness at all.
Then, as the conversion process is amply illustrated, it explains the difference between atsui katachi, atsui gokei and atsui keisei (the character for katachi and kei is the same = shape). I've only browsed through the book so far and I haven't got my head round this distinction - especially gokei. I've never come across this before.
The method of teaching is first to give a preamble for each section talking about definitions and theory. It seems to be very high level stuff, tersely written without the usual padding. Then examples (sorry, Robert), but a notable feature here is that rather than opening or middle game positions with a few key moves this book gives complete and well annotated games so that you can see the effects of atsumi evolve fully. My first impression is that atsusa only becomes truly evident at the endgame stage, so this would make sense if so.
There are a couple of other books in the same series. One is thinking about kikashi. The other is on countermeasures against overaggressive players.
This all strikes me as a pretty useful syllabus, and my first impression of the thickness book is that it sets a new high standard. It goes well beyond the invaluable Attack and Defence, I suspect. I'd be interested to hear what other readers think of it. It's probably too advanced to merit translation, unless a publisher is willing to take the long view.

What we knew (or rather , "were told", let's remain modest ;-) is that atsumi is for attacking, not fencing off territory. We were also taught that the objective of attacking can be killing groups (the objective most of us figure out by ourselves), but more commonly also making territory, gaining further atsumi, or something else that puts us ahead from a point of view of the balance of power and the balance of territory. Now from the above it seems that either: - there is another process than attacking to convert your atsumi in go, which could lead us to new ideas to plan our games; or - the attacking process is largely the same, but it is executed with another objective in mind than the usual ones I heard before


-- JanDeWit: This page looks strange right now! No line breaks anywhere to be found... In case it matters, I'm using IE5.5 on Win98...

-- TakeNGive: I think it was a copy-n-paste problem -- paragraphs were turned into "preformat" text. I couldn't stand it, so i made it into a "term:definition" list that looks kinda like "blockquote." I hope that's okay.

-- Stefan: That's a neat trick, TakeNGive! I didn't know about that one yet. Thanks for cleaning up my mess :-)


Newsgroups: rec.games.go From: "John Fairbairn" <johnfair@harrowgo.demon.co.uk> Subject: Re: Thickness for 5-dans Date: Sun, 16 Dec 2001 19:46:48 -0000

Here, rather brutally translated, is the intro to Part 2 of The Book.
VARIOUS KINDS OF THICKNESS
When we say "thick" (atsui) the usual image that comes to mind is "thick shape" (atsui katachi). However, you must appreciate that there are, in addition, a "thick game" (atsui go) and thick states (atsui keisei). We shall begin by distunguishing them.
"Thick shape" is also called "thickness" (astumi). The condition for atsumi is that remains stable even if the opponent approaches. If stones are simply facing the centre, they may have "influence" but they are not atsumi.
These thick shapes are in most cases acquired as compensation for giving actual profit to the opponent. It is clear, therefore, that the need to convert the atsumi somewhere or at some time into actual profit follows from the fact that the final result of the game is decided by the sizes of the territories.
If possible, you should want to convert your atsumi in to actual profit at an early stage by using it for attacks or moyos. However, there is a proverb that says "Do not play close thickness" and so chances to do this in the opening are not easily grasped.
Consequently, you turn your atsumi into atsusa and so bring about, overall, a "thick(er) game" (atsui go). If you get a thicker game, you are likely to be able to keep the initiative and to make decisive incursions by aiming at favourable trades.
With a "thick game" you have a margin in your favour in the power relations on the board, and you can bring the game to a "thick(er) state" (atsui keisei) without any tightrope walking. A thicker state is one where slightly but somehow it seems better for you. The various extra profits (yotoku) that are associated with atsusa will in the end materialise as a favourable position.
Kos often become a weapon when there is a thick shape, thick go or thick state. Even if a ko is not actually started, merely the possibility that it can arise can cause the opponent to retreat. It is a fundamental make-up of a position that there are no ko threats against atsusa and lots against thinness.
Attitudes towards atsusa differ in the opening, middle-game and endgame. However, the basic undercurrrent to all of them is a "thick way of playing".
Note from JF
Atsui go is tricky because go can be used to mean go, game, match and style. Normally when a pro says he has atsui go he means he has a thick style. That is not the meaning here, however, and that is probably why, when each of the listed types of thickness are discussed in detail later in the chapter, atsui go is changed to the new (?) term atsui gokei. Keisei = state refers to a well developed situation, and in go usually refers to a position where territories are not sealed off but are fairly well defined - they are countable in the sense of counting during a game. The Japanese word for this kind of counting is keisei handan (aka assessment of prospects).
Each of the three types of thickness are discussed next in the book by means of rather a lot of diagrams. I do not intend to deprive you of the joys of buying the book to learn more, but I will give a couple of examples from the thick shape section as I think they will surprise some people. Incidentally, despite what was said above, there does seem to be a gradation from atsui katachi to atsumi.When an atsui katachi is attacked and stones are added in its defence, the book says of one example: "This is also atsui katachi. Or perhaps such shapes are more generally acknowledged as atsumi." Another significant sentence is: "Solid groups which are clearly alive = atsui katachi."
1. The joseki: c4, e4, e3, f3, d3, f4, c6, k4 (or k3 - nb omitting i). In this position the positions of BOTH sides are thick. If k4 is omitted the three outside stones are NOT thick. Diagram: [1]
2. The Takemiya joseki: c4, e4, e3, f3, d3, f7. Is this outside shape thick or thin the book asks. It says one point of view is that it is thick because it does not fear attack. It has a cutting point but a cut leads to the outside player making a wall (this seems to be the only time wall is used in the book!). Diagram: [2]
3. The joseki: c5, d3, e4, e3, f4, g3, c10. The outside position is thick. However, it is the group as a whole that is thick. Take away the c10 stone and the wall left is not thick. Furthermore, if the other side now plays h3 (a "thick move"), the outside position is no longer thick. If the other side plays not h3 but g4, g5, h5, g6, h6, g7, h7, the h7 side's position is NOT thick because of the defect at h4. Diagrams: [3]
Compare all of this with traditional western views of thickness:
(a) From Jan van der Steen's Intergo dictionary: strong formation of stones facing the center or facing along a side
(b) From Sensei's Library: Thickness = Strength + Influence. Atsumi is a Go-term meaning "the influence of strong stones". We translate it into English with the word thickness. In order to be thick, a group of stones must be strong and it must have influence in a certain direction. [And also:] Influence is also refered to as thickness. Both terms, which have a slightly different feeling, can be a translation of the Japanese atsumi .

[1]:

[Diagram]
Diag.: Joseki

8 can also be at the marked point.


[2]:

[Diagram]
Diag.: Takemiya joseki


[3]:

[Diagram]
Diag.: Joseki

[Diagram]
Diag.: Continuation


This is a copy of the living page "Thickness" at Sensei's Library.
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