L'ame du go

  Difficulty: Intermediate   Keywords: Shape, Theory, Books & Publications

Fan Hui has graciously allowed the following material from his book L'âme du go - les formes et leur esthétique (The soul of go: shapes and their aesthetics) to be translated into English and here incorporated into Sensei's Library.[1]

Table of contents

Chapter 2 -- Four basic shapes

In the previous chapter we looked at basic shapes made up of stones of only one colour. In this chapter we will look at basic shapes made up of both black and white stones.

There are four basic shapes which are seen frequently in any game. They are common shapes because they are efficient[2].

A) The ripped[3] keima

[Diagram]
A ripped keima  

The two black stones in this diagram make up a keima, but the two white stones separate them: they "rip up" the black keima. The white stones are solidly connected, whereas the black stones are divided and weak. This is a very bad shape for Black.

You may say to yourself "Each player takes turns to play, so if White tries to cut, Black won't let it happen. So this is just a theoretical diagram and never happens in practice!". It is true that if White does play the first move of this shape (to prepare the cut) then Black will answer. However in Go common situations are always turning up in different ways. The next diagram gives a real life example.

[Diagram]
diag. 2  

This is the beginning of a handicap game. White plays W1 and Black answers B2. Next White normaly plays at W5, but here he[4] makes a tobi and jumps with W3. Next Black has played B4 threatening to cut, and White connects at W5.

How does one evaluate these moves? Who gets the better deal? Is there a name for this shape?

[Diagram]
diag. 3  

The shape is quite simply a ripped keima. The exchange is clearly good for White. White never made a preparatory move to rip the Black's keima. Rather, Black set up a keima to be ripped!

This sort of sequence frequently turns up in a game. If you don't pay attention, you can make bad shape without even noticing it. That is why it's important to know the ripped keima shape, so as to be able to avoid it early enough.


B) The ripped tobi

[Diagram]
A ripped tobi  

This shape is called a ripped tobi. As with the ripped keima, the white stones are solid and the black stones are separated and fragile. This is also a bad shape for Black.

[Diagram]
diag. 5  

It is as if White plays W1, threatening to separate Black, and Black does not respond to this threat. So W3 rips up Black's tobi.

[Diagram]
diag. 6  

Here is one way this shape can arise: White has just played W1, a contact move on an isolated black stone. How should Black answer?

[Diagram]
diag. 7  

Can Black attack White's stone with B1? This seems like a very severe move, don't you think?

[Diagram]
diag. 8  

White simply moves up with W2, and we have a ripped tobi: the two white stones have ripped up the black stones. Conclusion: B1 in the previous diagram is no good.

[Diagram]
diag. 9  

Clearly B1 is no good either, otherwise White can make ripped keima, giving Black bad shape.

[Diagram]
diag. 10  

Black doesn't need to look for overly severe moves. Either she can move up with B1 or play a hane at 'a', reinforcing Black's first stone.

If after B1 White reinforces his weak stone with 'a', Black has a very good move to attack White, as we shall see later on.


C) The elephant's eye

[Diagram]
diag 11  

This is a rather special shape called an elephant's jump. It's quite different from a keima and has one weak point.

[Diagram]
diag 12  

Play in the middle of the elephant's jump! This move is called the elephant's eye and is the vital point of the shape. The shape is good for White.

But: there is only one white stone and two black ones! How can this be good for White?

[Diagram]
diag 13  

Black has only two ways to surround White's stone: 'a' or 'b'. Note that the four points marked 'a' are symmetrical, as are the two points 'b'.

[Diagram]
diag 14  

What happens if Black plays B1 ('a' in the previous diagram)?

White plays W2. Now look at B1 and black+circle: together with the two white stones, they form a ripped keima. Black has let White make good shape!

[Diagram]
diag 15  

If Black plays a tobi to try to connect her stones, White will clearly cut. Here again we see a familiar shape: a ripped tobi, equally good for White.

[Diagram]
diag 16  

When White plays W1, Black cannot find a good move locally. Both 'a' and 'b' give White good shape. Black's two stones have no way of connecting up with each other.

Hence, the elephant's eye is a very powerful shape.


D) Hane at the head of two stones

[Diagram]
diag. 17  

In order to understand this shape, one has to know what a hane is.

In this diagram B1 is at a diagonal with respect to the black stone already present. If this move is made in contact with one (or several) white stones, we call it a hane.

[Diagram]
diag 18  

The marked black stones in this diagram illustrate different types of hanes.

[Diagram]
diag. 19  

This diagram shows a hane at the head of two stones. This special sort of hane is a very powerful move!

Imagine, for example, two people of the same size, White and Black. If Black gets to push White's head down, then Black will be higher. Black gets the high ground and opportunities to enlarge her territory. White has to take second place.

[Diagram]
diag. 20  

If White plays the hane W2 after the hane B1 - answering a hane with another hane - Black can simply fall back peacefully at B3. Black's head is still in front of White's, and White's shape has a cutting point, which is quite a burden on White.

[Diagram]
diag. 21  

In this position Black starts with one extra stone than in the previous diagram. As she has a stronger shape, she can play a double hane. White has to retreat at W4, and then Black connects at B5, getting strong central influence.

[Diagram]
diag. 22  

If White tries to cut with W4, Black connects at B5. Locally Black has more stones than White and Black's shape is much stronger than White's, so White is in a very dangerous situation.

[Diagram]
diag. 23  

If White chooses to play atari on the other side, at W4, Black connects at B5. Then Black has a ladder at 'a' and an atari at 'b' as possible follow-ups. In both cases White is in trouble.

For all these reasons, it is said that a hane at the head of two stones is a very important move.

In the previous pages we have presented four fundamental shapes. We now shall explore these shapes by looking at two common examples.

E) Two common examples

Example 1

[Diagram]
diag 24  

White has a two-space extension. As White's stones are attacked from both sides, White should protect them with a move at 'a'. As White has omitted this move, how should Black attack?

[Diagram]
diag 25  

B1 is a mistake as W2 makes an elephant's eye which is bad for Black.

[Diagram]
diag 26  

How about the attack at B1?

Remember each line has its own function. The second line is reserved for yose, and for living or killing. It's rarely used for attacking. Black clearly can't kill with B1. At the end of the sequence White has good shape for moving out. As well, W2 reduces the top right corner. The conclusion is that as Black can't hope to kill White, B1 is not good.[5]

[Diagram]
diag 27  

If Black merely plays the tobi B1 in this diagram, she lets White off easily. White is happy to play W2 and make comfortable shape. This is not a success for Black!

[Diagram]
diag 28  

The correct way to attack is with a keima at B1. If White answers with another keima at W2, Black can play in the middle at B3, making an elephant's eye.

[Diagram]
diag 29  

White can't then play W4 as Black makes the ripped keima. This is very bad for White.

[Diagram]
diag 30  

Similarly, Black also rips up White's shape with W5. This is good for Black.

[Diagram]
diag 31  

White tries to close Black in with W4 but B5 makes another ripped keima!

[Diagram]
diag 32  

What if White tries to trap Black with the tobi W4? Black moves down with B5, and if W6 connects then Black pushes at B7 and then makes the diagonal move B9. Black now has a way out at 'a' and at 'b'. Also, there are two cutting points in White's shape at 'c' and 'd'. White can't protect them both. Black is satisfied with this result.

[Diagram]
diag 33  

If White defends with W2 then Black can play B3 and White has to defend W4. B5 pursues the attack. Black is doubly satisfied as her shape is nice and White's stones are still unsettled.

If White omits W4, then Black plays there instead. If White then connects at 'a' then Black makes a keima at 'b', separating White's stones. This result is even better for Black!

[Diagram]
diag 34  

The keima at B1 is thus the right way to attack. This move is a common way to attack, particularly for attacking two-space extensions. That's why it is very urgent for White to be the first to play in this area, preferably with a reinforcement at 'a'.


Example 2

[Diagram]
diag. 35  

White is under attack, and has just moved out with W1. How should Black pursue the attack?

[Diagram]
diag. 36  

Black may try a direct attack at B2. But White moves out with W3, making a ripped tobi. If Black cuts at B4, the moves to W9 follow. Black has captured one stone, but White is satisfied with settling his stones.

[Diagram]
diag. 35  

If Black tries to cut straight away, what happens? White answers at W3, then Black connects and White connects. Once again, we get the ripped tobi. As the black stone on the left is damaged, this is good for White.

[Diagram]
diag. 38  

The hane at B2 seems normal, but White calmy moves forward at W3, making an elephant's eye! Black cannot then push in either direction, as otherwise White will make a ripped keima. Also, White has a cutting point at 'a', so it's hard for Black to find a follow-up to for her attack.

[Diagram]
diag. 39  

The right way to attack is to fall calmly back at B2. If White pushes at W3, Black gets to play a hane at the head of two stones! Black may even get to play a double hane at B6, which is bad news for White.

[Diagram]
diag. 40  

If White plays tobi W5 to move out, Black exchanges B6 for W7 and then also plays a tobi with B8. After this White's stones are very heavy and Black has made position on both sides, which is an excellent result for her.

[Diagram]
diag. 41  

If White moves out with a diagonal move, Black simply follows. Black's stones on both sides are well placed; Black can be very happy with this result.

[Diagram]
diag. 42  

Summing up this example, Black can simply draw back with B2, avoiding unnecessary complications. This is a situation where Black has to avoid pushing White.



[1] This translation was made mostly by Malcolm, with Fan Hui's prior consent.

[2] Malcolm: I think the idea is that the shapes are efficient for one of the players.

[3] Malcolm: sundered keima, sundered tobi would also be good translations of traverse-keima, traverse-tobi.

[4] Malcolm: Following one of Berlekamp's books, I've decided White is male (Right White) and Black female (Belle Black) here.

[5] ajs3: 38 Basic Joseki suggests that this attack is a success for Black (p. 55, dia. 2). Locally the diagrams (i.e., in this wonderful excerpt and in the aforementioned book) are identical, but the corner positions are different.


L'ame du go last edited by Malcolm on May 15, 2015 - 10:42
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