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© 2014 Slate & Shell

Invasions

Making and Defending Against Invasions into Common Positions

Iwamoto Kaoru 9 dan

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Originally published in Japanese by the Nihon Ki-in

Translated by T. Ogoshi with assistance from Roger A. Newlander and initially published in the American Go Journal.

The permission of the Nihon Ki-in for the continued use of this material for the promotion and development of go in the West is greatly appreciated. It was initially translated by T. Ogoshi with the assistance of Roger A. Newlander and edited by Don Wiener for publication in the American Go Journal in the 1980’s. It was then re-edited and republished by Slate & Shell as part of Keshi and Uchikomi: Reduction and Invasion in Go which has been out of print for several years. The section on invading has again been re-edited for this publication with substantial reworking of both the diagrams and the text, correcting some errors. A new edition of the material on reducing is also planned.

Introduction

“Invasion” in go, uchikomi in Japanese, is a direct attack inside the opponent’s intended territory. The aim is to deprive the opponent of area that has not yet been fully defended. This usually involves placing a stone inside the opponent’s formation that you must save in order to succeed in the attack, either by running out or by living inside the opponent’s position. Sometimes the initial invading stone can be used as a sacrifice to gain benefits. That is, an invasion can sometimes turn into a reducing move (keshi in Japanese), though reducing moves normally press on the opponent’s position from the outside. In this volume the focus is on direct invasions. Reducing moves will be the subject of a separate book.

Diagram A

The essential point to remember when considering an invasion is that one must not enter an area only to help the opponent consolidate an even larger area. Diagram A is an example where there is room for an invasion into the black area on either the right or the upper side. However, an invasion into either of these areas may enhance Black’s outside influence, consolidate the other side, and also threaten the invading forces. These considerations are especially important when the area is fortified by extensions from both sides (the stones) as here. In such cases one must not try an invasion, but instead use the reduction techniques to be discussed in the later book on reducing.

Iwamoto Kaoru

Copyright Page

© 2014 Slate & Shell

All rights reserved. Reproduction in whole or in part is prohibited.

Slate & Shell
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Edited by William Cobb and Richard Hunter

Cover design by Laurie M. Crammond

Conversion to SmartGo Books by William Cobb and Richard Hunter

ISBN of print edition:
1–932001–69–7

Table of Contents

Invasions: Making and Defending Against Invasions into Common Positions

Introduction

Copyright Page

The chapters in gray are included only in the full book.

Formation 1

Formation 2

Formation 3

Formation 4

Formation 5

Formation 6

Formation 7

Formation 8

Formation 9

Formation 10

Formation 11

Formation 12

Formation 13

Formation 14

Formation 15

Formation 16

Formation 17

Formation 18

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Formation 1

Formation 1

In Formation 1, White wants to invade Black’s formation. Let’s consider the points A–D.

Diagram 1

If White invades at 1, Black can easily respond with 2 and then cut off White 3 with Black 4. This sequence could also occur by White starting at 3, followed by Black 4, White 1, and Black 2.

Diagram 2

White can invade at this 1. Answering with Black 2 is common. White 3 and Black 4 may follow, making a general advance into the center. Black has secured the corner and has A to aim at. This sequence is not disadvantageous to Black.

Diagram 3

Against this White 1, Black has the simple reply at Black 2. White 1 has little effect on the corner and is floating by itself. It lacks power and does not deserve consideration.

Diagram 4

If White 1 is here, the jump to Black 2 is a common reply that is suitable when Black does not aim to surround the invader. (Attempting to surround White usually results in trading outside influence for White’s group living inside—more later about that.) White could slide toward the corner with 3, but not far enough to menace Black’s base. That play is likely to result in White having a burdensome group later. Black could also play 4 at A.

Diagram 5

Black can also respond to this White 1 by putting more pressure on White with 2. White 3 is flexible and White’s best response.

Diagram 6

White could play 3 this way, but Black 4 makes White a little uncomfortable. See the possible continuation in Diagram 7.

Diagram 7

After White 5, White cannot avoid being pushed around while Black develops considerable outside influence. White’s gain from the invasion is offset by the dangers created by Black’s growing strength in the center.

Diagram 8

After this White 3 (as in Diagram 5), Black could play this 4. It forces White 5 and Black simply leans with 6. White 7 accomplishes little. Black 4 denies White a base and White has not seriously disturbed Black’s area.

Diagram 9

If Black simply jumps out with 4, White gets some shape by playing 5 at that point. So this point is key to both attack and defense. It is very important to grasp the difference between Diagrams 8 and 9.

Diagram 10

Black can attack more strongly with this 4. After White 5, Black stops White at 6. White 7 follows, and …

Diagram 11
12 at

… Black can then hem White in.

Diagram 12

Play might continue like this. After White’s cut with 17, …

Diagram 13

… Black must connect with 18, after which White would make a live group through White 25. White’s invasion has lived, but Black has sealed White in and can gain considerable outside influence with a play around A.

The only possible worry for Black in this case is a move by White against the four black stones including 20 and 22, but it is doubtful that White can succeed by starting to move out to the left from 17 immediately. If this is a worry for Black, a different line such as that in Diagram 4 can be chosen.

Diagram 14

The reason for playing White 17 as in Diagram 12 (at 19 here) is that if White captures a black stone with this 17 instead, as here, Black would play 18 and later Black would not need a stone at A whereas Black does in Diagram 13.

Diagram 15

Black 4 here is not recommended because White gains an advantage by playing this 5. If Black wants to attack, Diagram 10 should be followed.

Diagram 16

Another possibility that may not be obvious is to play White 3 this way. Play may continue as in the next diagram.

Diagram 17

White can make an invasion all right so this is a plan White can consider, but Black has consolidated the corner by attacking White. So this position is not bad for Black either. After White 9, Black would probably jump out to A.

Diagram 18

Going back to this White 3 (as discussed in Diagram 6), if Black instead plays 4 this way, the position can revert to Diagram 10. This is not as good for Black as Diagram 6.