3-4, 5-3 enclosure, 4-3 invasion
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is basic instinct.
Without neighbouring stones, White will often sacrifice and treat and as forcing moves, serving to create something at the top.
If White has neighbouring stones, she can start thinking about persisting with the invasion. If the stones are far away, Black can still kill the invasion. But his surrounding position is quite thin and if the conditions become favourable, White has a possibility to cut and make a fight of it.
If is this atari, then White can make a ko-fight of it. Usually this type of ko is a I-lose-nothing-ko. Any compensation for the group is good.
This pattern appears often when black is strong. In fact, white will sometimes tenuki after this and come back to do something with it later.
If White is considered very strong at the outside, Black could also consider this move for defending (see sabaki for a continuation). This is also discussed at light play example 4
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).
Pattern searching on Jan's incredible database at gobase.org comes up with several games including the light play version.
These first three show the White kosumi-tesuji continuation on the 2-2 point:
- Takagawa Kaku (B) vs. Kitani Minoru 1963-12;
- Takagawa Kaku (B) vs. Kitani Minoru, 1964, 19th Honinbo League, Round 5;
- Hotta Seiji vs. Hiroe Hiroyuki, 1990-02-22, 31st Okan,31, Japan, Round 2.
- 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.
- 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.
- 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.
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.