[Welcome to Sensei's Library!]

StartingPoints
ReferenceSection
About


Paths
InvasionItinerary
EnclosureTechniques

Referenced by
Invasion
34PointEnclosureJ...
InvadingAndReduci...
BQM7ASuitableCase...

Homepages
HuOfKGS

 

Invading an Enclosure
Path: EnclosureTechniques   · Prev: TheSmallLowEnclosureIsSecure   · Next: DefendingAnEnclosure
Path: InvasionItinerary   · Prev: Uchikomi   · Next: InvasionsOnTheSide

    Keywords: MiddleGame, Joseki, Tactics

It is not recommended that you invade an enclosure (shimari) before you get strong on the outside. But with a strong position in the center and in the case when the influence Black gets is not going to help much, go for an invasion.

[Diagram]
A very good place to invade


Here's something I remember from my first series of Go articles I read a quarter of a century ago.

[Diagram]
How Black kills the invasion

But it is quite thin and if the surroundings are favourable, White has a possibility to cut and make a fight of it.


[Diagram]
Ko

If B8 is this atari, then White can make a ko-fight of it. Usually I consider this type of ko as an I-lose-nothing-ko, which is a very pleasant ko to fight. Any compensation for the group is good.


[Diagram]
Black 2 is worth considering. Is it also safer?

If White is considered very strong[1] at the outside, Black could also consider this move for defending (see sabaki for a continuation). I did a little bit of pattern searching on Jan's incredible database at [ext] gobase.org because I was not so sure anymore whether Black should play like this, i.e. the 4-2 hane. GoBase.org came up with several games, including one with the exact position:

These first three show the White kosumi-tesuji continuation on the 2-2 point: (1) Takagawa Kaku (B) vs. Kitani Minoru 1963-12; (2) Takagawa Kaku (B) vs. Kitani Minoru, 1964, 19th Honinbo League, Round 5; (3) Hotta Seiji vs. Hiroe Hiroyuki, 1990-02-22, 31st Okan,31, Japan, Round 2.

In the first two games Black is very, very strong on the outside - very different from the diagrams up here where White is strong - and White uses the 5-5 shimari reducing move first, i.e. before the displayed moves. Similar but a little bit less strong is the Black position in the third game.

(4) Ishida Atsushi (7p) vs. Kawamura Kazunori (8p), 22nd Tengen title, Prelim. rd. 1, game 11, 1996-03-07 is the only professional game which had a part of the upper position in actual play. This could mean that it is playable :-)

(5) Go Seigen, 3 dan vs. White Sekiyama Riichi, 4 dan, Oteai, 1930-04-02,03 in Round 5 (of 8) of spring session of the Nihon Ki-in Rating Tournament is one game with the position of the above ko diagram.

(6) 13th Japan-China Go Exchange, Round 1, Ma Xiaochun 9p vs. Ishida Akira 9p, 1985-05-28 shows one game where ko is avoided (Black was very strong in the shimari environment) and a different fight results.

[1] This way of playing seems more appropriate if Black, not White, is strong and has stones around the side-hoshis. See for example part 9 of Charles Matthews excellent 'Setpiece Kos' series. There, move 2 above leads to an interesting ko (colors reversed). In the next diagram you can see that the whole situation could also appear starting with W1 at 3:


[Diagram]
Black 8 at 3

[Diagram]
The 2-2 kosumi tesuji

White will have played already a and b before starting to move into the corner.


[Diagram]
White connects and can cut or live

All positions where White connects solidly are ones where White already has the circled or at least the squared peeping stone. White's options are thus cutting or living. White is strong in the surroundings and these moves therefore appear quite late in the games, much later than in the above examples. -- Tommie?

Dieter: I think this is not correct: Black will connect at a and White can only make an L+1-group with b. Next, Black kills playing c.

TDerz: Sloppy of me. Then I should better only state that the solid connection appears in professional games, e.g. no. (6) above and be silent about the reasons why they played it. If Black connects at a, then Black can be cut at d. If Black were connecting both at a and d, White could also play two moves b and e needed for living. As said above, the strong surroundings make the difference and this certainly cannot be generalized. It is fighting and can only be read out.



[Diagram]
Preventing invasion

This B1 is a useful play to know about in the oyose (early endgame). It corrects the aji in the enclosure, when White is strong locally.

Charles Matthews


[Diagram]
Protects the future cut?

It's because B1 protects the cut at a, right? - Fhayashi

I'd say it has more to do with playing B5 safely at b, instead. -- Charles



Path: EnclosureTechniques   · Prev: TheSmallLowEnclosureIsSecure   · Next: DefendingAnEnclosure
Path: InvasionItinerary   · Prev: Uchikomi   · Next: InvasionsOnTheSide

This is a copy of the living page "Invading an Enclosure" at Sensei's Library.
(OC) 2003 the Authors, published under the OpenContent License V1.0.