4473 enclosure

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    Keywords: Opening, MiddleGame, Joseki
[Diagram]

4473 enclosure

This is a common way to develop from a 4-4 point.

(Black a creates the KannonBiraki formation.)

tderz ("a") ... which is bad for Black, because White can still live by san-san. Black b really protects the corner.

Hence, the alternatives in this position are:

  • not a
  • b (r has a bit more bad aji) or
  • a wide formation with a move around [circled point].
    • if such a wide formation has been created, then White will not invade anymore at san-san s (Moyo gets too big), but
      rather attach at p (cf. Chtito [200] below)



[Diagram]

The 3-3 invasion

This is the main variation of White's 3-3 invasion of the enclosure. B4 may also be played at W7 (see below).



For B2 at W3 see 4473 enclosure 3-3 invasion, block on inner side.

[Diagram]

Main variation, continued

tderz W3 or b.
Bd is then sente, White replies with e.
No matter how White connects, there is always a Black threat from the side.



This is the standard line, and White ends in sente. The White group is an L+2-group and is alive. Black though has considerable influence now.

Variants:

  1. W1 at a, challenging to a ko.
  2. W3 at b. This affects forcing moves (Black d is then sente against the corner), and endgame plays in the corner. With W3 as played, Black c threatens a ko in the corner.
  3. Black on occasion omits B4 net example 5, but then White at B4 causes a fight.

[Diagram]

Another way

Black may also play B1 this way. Then W2 (or a) lives. B7 here is proper, but may be omitted: if Black wants to end in sente here it may make sense to play B1 in this manner, rather than follow the above main variation.


Dieter: Question. B8 at a reduces the corner to an L+1-group, whose status depends on sente. So Black can play a in sente ?

[Diagram]

Kikashi

Here B1 is certainly a good kikashi against the corner. And B3 here is a useful way to follow it up, for fighting purposes, since it still threatens the corner. It is unlikely to be the correct endgame play, though, in typical situations.


Chtito: I have a question about an approaching sequence that I don't understand: [200]

[Diagram]

Corner Sequence

After B5, the sequence White a, Black b is played. Now my question is: why White does not play b instead of a? How would Black punish a white play at b?

[Diagram]

Usual shape

tderz: This W5 is better shape and played more frequent.

Then c, not b (too wide) would be played.
White replies at a (honte), not e (if s.o could link the apprpriate diagrams to here, they must be already on Senseis).

[Diagram]

your question - how to punish?

tderz: On the right (with the usual extension B1), White would simply punish by pressing black down while building influence herself.
Your question (the left side) is more difficult to answer.
If White proceeds as on the right, then Black gained a bit (in comparision to the right dia) because the extension is one wider.

[Diagram]

your question - how to punish?

tderz: W2-B5 is confusing, it depends a lot on the neighbouring stones. The exchange B2-W4 itself is bad for Black (cf. pushing on the 4th line?).
If there is one white stone below B1, then
White could descend with a, threaten connections b and c as miai.

Hence, I think the invasion W2 is feasible, because Black has to commit the unfavourable puush on the 4th line.

[Diagram]

Can White play this?

Charles Well, if B1 and W2 it becomes very dangerous for White. After B5 can White cut at the marked point? I don't believe so. In any case White was strong here first, so that White shouldn't have to fight in such a desperate way: it should be Black's problem to find good moves, and here it is White's.

W2 at B3 is quite bad, while W2 at W4 is possible but not really interesting.

tderz: White protects at b after B5, Black connects at [circled point], then White cuts at c and is much better off. Due to the presence of WC, blacks 3 stones have to fight in an unfavourable environment and will dammage B1-B3-B5 (which were bad style).
It is true that black d is sente against the corner, but that won't help so much.
B3 could have been played around m (connecting own stones - ladder works to the left - and threatening all the rest).


[Diagram]

Inverting the order

Dieter: If White inverts the order, he'll get into trouble with B8. Black can answer the cut at W10. Next, ...

[Diagram]

The fight

... the fight is influenced by neighbouring stones. If Black is strong in the area, White cannot hope for much. Therefor, ...

[Diagram]

The clamp

White may clamp but she'll be in dire straits anyway.


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