4473 enclosure
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
.
- 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)
- if such a wide formation has been created, then White will not invade anymore at san-san s (Moyo gets too big), but
This is the main variation of White's 3-3 invasion of the enclosure. may also be played at
(see below).
For at
see 4473 enclosure 3-3 invasion, block on inner side.
tderz or b.
Bd is then sente, White replies with e.
No matter how White connects, there is always a Black threat from the side.
Dave: However, the threat is different (which may affect the choice of connection), see below.
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:
-
at a, challenging to a ko.
-
at b. This affects forcing moves (Black d is then sente against the corner), and endgame plays in the corner. With
as played, Black c threatens a ko in the corner.
- Black on occasion omits
net example 5, but then White at
causes a fight.
Different Connection - Different Threats:
Dave: With the solid connection
here is sente. White can not live unconditionally if Black plays next at
. White is caught in dame zumari after
and can not intercept at a. If
were not on the board, White would live. Here White has no choice but to start a ko with 6 at 7. This is an indirect ko. Playing b instead of 1 does not threaten White.
Dave: With the hanging connection, White dies outright after
and
. The play at a instead of 1 does not threaten White.
Black may also play this way. Then
(or a) lives.
here is proper, but may be omitted: if Black wants to end in sente here it may make sense to play
in this manner, rather than follow the above main variation.
Dieter: Question. at a reduces the corner to an L+1-group, whose status depends on sente. So Black can play a in sente ?
Here is certainly a good kikashi against the corner. And
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]
After , 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?
tderz: This
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).
tderz: On the right (with the usual extension
), 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.
tderz:
-
is confusing, it depends a lot on the neighbouring stones. The exchange
-
itself is bad for Black (cf. pushing on the 4th line?).
If there is one white stone below, then
White could descend with a, threaten connections b and c as miai.
Hence, I think the invasion
is feasible, because Black has to commit the unfavourable puush on the 4th line.
Bill: is simple and effective. After
, because of
,
are obviously very inefficient.
Charles Well, if and
it becomes very dangerous for White. After
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.
at
is quite bad, while
at
is possible but not really interesting.
tderz: White protects at b after
, Black connects at
, then White cuts at c and is much better off. Due to the presence of
, blacks 3 stones have to fight in an unfavourable environment and will dammage
-
-
(which were bad style).
It is true that black d is sente against the corner, but that won't help so much.
could have been played around m (connecting own stones - ladder works to the left - and threatening all the rest).
Dieter: If White inverts the order, he'll get into trouble with . Black can answer the cut at
. Next, ...
... the fight is influenced by neighbouring stones. If Black is strong in the area, White cannot hope for much. Therefor, ...