Shape for DDKs -- and thickness, too!

Bill Spight · Post by **Bill Spight** » Sat May 30, 2015 10:32 pm

I have prepared some thoughts and material on the basics of shape and thickness. I by no means intend this thread simply to reflect my thinking and opinions. Please join in the fun.

Shape for DDKs

Discussions about shape often start out by classifying some shapes as bad, others as good. But IMO the basics of shape come before such classifications.

What is shape? A shape is a local configuration of stones of the same color. Shape as a topic is about the efficiency or effectiveness of shapes. The study of shape, then, includes how shapes relate to stones of the opposite color. Shapes can be overconcentrated, so that they use more stones than necessary to achieve their effect; they may even be heavy, so that not only do they invest a number of stones, they do not achieve their effect and are weak. On the other hand, shapes can use too few stones to achieve their intended effect, and can be thin and weak.

Suzuki Tamejiro, the teacher of Kitani Minoru, emphasized three basic two stone shapes for beginners, the nobi, a solid extension to an adjacent point, the kosumi, an extension to a diagonally adjacent point, and the tobi, a one space jump. The most frequent moves in go form one of these shapes. Depending on the circumstances they often go by different names. Of course, in themselves we cannot say whether these shapes are good or bad; we have to take into account their surroundings. I will also emphasize these shapes, as well as another one, the keima, or knight’s move, an extension two points in one direction and then one point in a perpendicular direction.

Click Here To Show Diagram Code: [go]$$B Nobi $$ . . . . . . $$ . . . . . . $$ . . X 1 . . $$ . . . . . . $$ . . . . . . $$ . . . . . .[/go]

Locally the nobi is strong. It cannot be cut. It is also slow.

The next two diagrams show the nobi with an opposing stone.

Click Here To Show Diagram Code: [go]$$B Nobi (ii) $$ . . . . . . $$ . . . . . . $$ . . X 1 . . $$ . . . O . . $$ . . . . . . $$ . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$B Nobi (iii) $$ . . . . . . $$ . . . . . . $$ . . X 1 . . $$ . . O . . . $$ . . . . . . $$ . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$B Kosumi $$ . . . . . . $$ . . . . . . $$ . . X . . . $$ . . . 1 . . $$ . . . . . . $$ . . . . . .[/go]

The kosumi develops more quickly, but it is not as strong as the nobi. It can be cut if Black ignores the threat to cut. The next diagrams show the kosumi with one or more opposing stones.

Click Here To Show Diagram Code: [go]$$B Kosumi (ii) $$ . . . . . . $$ . . . . . . $$ . . X . . . $$ . . . 1 O . $$ . . . . . . $$ . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$B Kosumi (iii) $$ . . . . . . $$ . . . . . . $$ . . X . . . $$ . . O 1 . . $$ . . . . . . $$ . . . . . .[/go]

This kosumi, AKA hane or block, is an attacking play, but it can be cut.

Click Here To Show Diagram Code: [go]$$B Kosumi (iv) $$ . . . . . . . $$ . . . . . . . $$ . . X X . . . $$ . . O O 1 . . $$ . . . . . . . $$ . . . . . . .[/go]

This hane is normally a very good play. Go proverb: Don't look, hane at the head of two stones.

Click Here To Show Diagram Code: [go]$$B Kosumi (v) Counter hane $$ . . . . . . . $$ . . . . . . . $$ . . O X . . . $$ . . . O 1 . . $$ . . . . . . . $$ . . . . . . .[/go]

Many players are unaware of this play, but it is normally a good one.

Click Here To Show Diagram Code: [go]$$B Tobi $$ . . . . . . $$ . . . . . . $$ . . X . 1 . $$ . . . . . . $$ . . . . . . $$ . . . . . .[/go]

The tobi develops even more quickly, but is weaker than the nobi or kosumi. White to play can cut it — but usually does not.

Click Here To Show Diagram Code: [go]$$B Tobi (ii) $$ . . . . . . $$ . . . . . . $$ . . X . 1 . $$ . . . . O . $$ . . . . . . $$ . . . . . .[/go]

This jump attachment is often seen.

Click Here To Show Diagram Code: [go]$$B Keima $$ . . . . . . $$ . . . . . . $$ . . X . . . $$ . . . . 1 . $$ . . . . . . $$ . . . . . .[/go]

The keima, or knight’s move, is quicker than the tobi, but, curiously, harder to cut.

Click Here To Show Diagram Code: [go]$$B Keima (ii) $$ . . . . . . $$ . . . 5 . . $$ . . X 2 . . $$ . . 4 3 1 . $$ . . . . . . $$ . . . . . .[/go]

White may cut with :w2:

and

, but

may be able to capture :w2:

in a ladder.

Click Here To Show Diagram Code: [go]$$B Keima (iii) $$ . . . . . . $$ . . . . . . $$ . . X . O . $$ . . . . 1 . $$ . . . . . . $$ . . . . . .[/go]

is often seen.

Bill Spight · Post by **Bill Spight** » Sat May 30, 2015 10:36 pm

On studying shape

Aside from excellent material in books and online, professional games provide a wealth of material on shape, because almost all pro moves are locally efficient, and therefore are good shape.

You just have to examine them from that standpoint.

The basics of efficiency

A number of years ago I studied professional plays in local contexts. At first I categorized them in terms of the number of Black stones and number of White stones. But I discovered that a better classification was in terms of the total number of stones and the difference between the number of Black stones and White stones. What I discovered about efficiency can be applied even by beginners.

The first principle of efficiency is that the efficiency of a shape or move decreases, in general, with the total number of stones of either color in a local area. The main exception is when a move captures a number of stones or saves them. This is obvious on the whole board, as moves become worth much less at the end of the game than they were at the beginning. But it also holds true, as a rule, in local situations. As they start to become settled, it is often time to play somewhere else.

The second principle of efficiency is that the efficiency of a shape or move decreases, in general, with the difference between stones of different colors. The most frequent plays are those that start from an equal number of stones by each player, so that one player gets one stone ahead, or those that end with an equal number of stones, so that one player catches up. The next most frequent plays are those where a player adds a stone from two stones behind, or where he gets two stones ahead. Getting three stones ahead in a local area is often inefficient. Not that it never happens, but in general it is to be avoided.

The second principle is related to the first. For instance, suppose that the players have played in four different local areas of the board, one stone in each of three areas and five stones in the fourth. The plays in the fourth area are likely to be less efficient than the other plays. Suppose also that one player has played only in the fourth area, while the opponent has played one stone in each. In the fourth area that player is three stones ahead, but by the first principle as well as the second, his stones are likely to be less efficient that the stones of the opponent.

Bill Spight · Post by **Bill Spight** » Sat May 30, 2015 10:38 pm

Strength and thickness

It is, in my opinion, important for DDKs to learn to make strong shapes and to play thickly. (I speak from the opposite experience. At that level I did not play thickly.) While it is true that strong shapes can be slow and thus inefficient, weak shapes invite disaster. Once a player has made thick, strong shapes, she can then use those shapes to attack the opponent’s groups. The attacking moves need not be, and usually are not thick, but thinner and quicker. Thus the attacker avoids developing too slowly. Many players bemoan the fact that they do not understand how to utilize thickness. If they had started out playing thickly and using that thickness to attack, they would not have that problem.

Because of the danger of playing slowly when making thickness, handicap games, particularly high handicap games, offer a good practice field to learn thick play and attack. A little slowness will not lose the game. I have usually recommended that players who wish to advance take handicaps of 5 stones or more. For DDKs wishing to learn about thickness and attack, I recommend taking handicaps of 7 - 9 stones.

Hattori Inshuku, founder of the Hattori School, wrote a multivolume set about handicap go openings called Okigo Jizai. In his high handicap volumes he shows how to make thickness and use it to attack. Though it was written two centuries ago, and shows it, handicap go has not changed all that much since then, especially high handicap go.

Next I will use some high handicap variations from Okigo Jizai to illustrate how to make thickness and how to use it.

Bill Spight · Post by **Bill Spight** » Sat May 30, 2015 10:40 pm

A nine stone game from Okigo Jizai.

Enjoy!

Bill Spight · Post by **Bill Spight** » Sat May 30, 2015 10:42 pm

A seven stone game.

Krama · Post by **Krama** » Sun May 31, 2015 11:19 am

At first diagram I would play black 28 at N15.

Joelnelsonb · Post by **Joelnelsonb** » Sun May 31, 2015 11:52 am

Thank you very much for this! There can never be too much information on fundamentals.

Bill Spight · Post by **Bill Spight** » Sun May 31, 2015 2:55 pm

Krama wrote:At first diagram I would play black 28 at N15.

That may work out. But you should be aware that that play, a kosumi, generates a weakness for Black, since Black cannot afford to give up the N-15 stone.

Hattori's hane undercuts White's potential base while making a base for Black. Such plays are big.

oren · Post by **oren** » Mon Jun 01, 2015 10:14 am

Bill, have you seen this book?

http://www.amazon.co.jp/%E7%AD%8B%E5%A0 ... 4062192357

It's an interesting discussion on shape with good examples as well.

John Fairbairn · Post by **John Fairbairn** » Mon Jun 01, 2015 11:35 am

It's an interesting discussion on shape with good examples as well.

Yes. I await the book. So far I've only seen this on Yoda's blog but if the early promise is sustained this will be a major contribution to go theory for amateurs. It's a kind of tewari, but it seems to work for all contact fights.

The key word is sujiba, which is word Yoda made up. It denotes certain key liberties.

Imagine an independent line of connected same-colour stones. Let's say two. These have six liberties, but sujiba refers to the liberties on the wall sides, four in this case.

Imagine two lines, one white, one Black, of three stones facing each other a space apart somewhere away from the edge. Each line of stones has six sujiba, and three of them are shared.

The basic premise is that it is inefficient to play on a sujiba, so if you look at a completed position and see any stones on sujiba, you have spotted a likely inefficiency.

Yoda's technique is to illustrate his theory mainly by re-examining standard proverbs. With the caveat that I've only seen a few examples, it is impressive stuff. One example is the crosscut. Weak amateurs tend to respond by playing Atari on both sides, but when the opponent extends out of Atari, the end result is that the atari-er has inefficiently played on sujiba. So the proverbial advice to extend one side from a cross-cut is justified. Obviously, just like tewari, sujiba is not a magic bullet, but it does seem that if you treat walking on sujiba like walking on the cracks in pavements, you are much less likely to trip up.

He mentions that amateurs probably haven't heard of this, apparently implying that pros already know about it, but not under any special name. Given Yoda's track record of revealing major insights into pro techniques, this too seems plausible.

Bill Spight · Post by **Bill Spight** » Mon Jun 01, 2015 11:37 am

oren wrote:Bill, have you seen this book?

http://www.amazon.co.jp/%E7%AD%8B%E5%A0 ... 4062192357

It's an interesting discussion on shape with good examples as well.

Looks interesting. Thanks.

EdLee · Post by **EdLee** » Mon Jun 01, 2015 1:10 pm

Question for those more proficient in Japanese:

The bottom marketing quote:
「3目強くなることを私が保証します」(依田紀基)
Does it say -- I guarantee a 3-stone improvement,
or a 3-point improvement ?

oren · Post by **oren** » Mon Jun 01, 2015 3:53 pm

John Fairbairn wrote:He mentions that amateurs probably haven't heard of this, apparently implying that pros already know about it, but not under any special name. Given Yoda's track record of revealing major insights into pro techniques, this too seems plausible.

It's been a while, since I read the intro but my memory says that he mentions this theory is something he came up with while trying to teach. He runs a school, and he knew what good shape was, but no one knew how to really teach it. Then he noticed how virtually all good/bad shape could be taught with tewari and sujiba (which boils down to places that make empty triangles for you or your opponent. It's not just empty triangles of one color but for both players). I've gone through about half the book so far.

I think first was the videos for Igo Shogi channel and then the book.

http://www.nicovideo.jp/watch/1417099940

oren · Post by **oren** » Mon Jun 01, 2015 3:54 pm

EdLee wrote:Question for those more proficient in Japanese:
image.jpg
The bottom marketing quote:
「3目強くなることを私が保証します」(依田紀基)
Does it say -- I guarantee a 3-stone improvement,
or a 3-point improvement ?

It does look like 3 point improvement. I guess he doesn't expect it to help much.

Bantari · Post by **Bantari** » Mon Jun 01, 2015 5:35 pm

oren wrote:
EdLee wrote:Question for those more proficient in Japanese:
image.jpg
The bottom marketing quote:
「3目強くなることを私が保証します」(依田紀基)
Does it say -- I guarantee a 3-stone improvement,
or a 3-point improvement ?

It does look like 3 point improvement. I guess he doesn't expect it to help much.

3 points improvement for a pro might be more than 3 stones improvement for us.

Life In 19x19

Shape for DDKs -- and thickness, too!

Shape for DDKs -- and thickness, too!

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Re: Shape for DDKs -- and thickness, too!

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Re: Shape for DDKs -- and thickness, too!

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Re: Shape for DDKs -- and thickness, too!

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