2-4 Probe against a low corner enclosure

  Difficulty: Expert   Keywords: Joseki

Table of contents Table of diagrams
The probe
Outside block
book sequence, but rare
change of pace
change of pace
Reinforcing the outside
Taking the outside (B11 to B13 at ''a''-''b''-''c'')
No life in the corner (B4 at BC, W7 captures, W11 at ''a'', B12 at ''b'')
A modern variation, but why?
Preparing to attack
White gets the corner
A small life
Black plays hane
Tripod group
Under attack
Another attack
Blocking from the inside
Clamp
Pulling back
Pulling back

#3 #1 #4 #2 #5
[Diagram]
The probe  

White W1 probes against the low corner enclosure. His intention is usually to stop black from making territory in front of his shimari. Because the corner starts out as black territory, white has to play light and flexible. His stones will often end up being light or even downright sacrificed.

Local answers are hane at the outside (a) or inside (b), or stretch at the ouside (c) or inside (d). Finally the extension at e, though less common, is also played enough to be considered joseki.


[1] Blocking outside

[Diagram]
Outside block  

If black blocks on the outside with B1, white will play the crosscut of W2. Although books tend to focus on another variation (see below), B3 is by far the most common move for black. In this very standard sequence, black secures the corner territory, while white moves away to get some breathing space. The sequence from B3 to B9 is quite straightforward, though white might try a or b instead of W6.

[Diagram]
book sequence, but rare  

The move most often shown in the books is B3. In professional play it is not non-existent, but it is rare, being too territory-oriented and foregoing a chance to put pressure on white.

After B7, it would be a mistake for white to play at a though. As they stand, white's stones are light and easily discarded, but playing W8 at a makes them heavy. Instead, white should jump out lightly, for example at W8 (the exact location depends on the position) or even play tenuki. White should treat his stones at W2, W4 and W6 very lightly. Black has answered them on the inside, so they are easily sacrificed.

See also probe popular misconceptions.

[Diagram]
change of pace  

There are two more possible continuations for black. B1 leads to an exchange, where black takes the position at the top that white was trying to avoid, but at the cost of not only giving white the left side, but also losing some of the corner territory.

[Diagram]
change of pace  

B1 followed by B3 is usual when the white stone at white+circle is present. After the usual move B1 at W2 or an immediate atari at B3, white+circle ends up in a useful position. The exchange of B1 for W2 makes white heavy. If black plays B3 immediately, then plays atari at B1 after W4-B5-W6-B7-tenuki, white will probably play at a, not at W2.


[2] Reinforcing the outside

[Diagram]
Reinforcing the outside  

After B1, white has two answers, W2 and a. In both cases black still can choose between the corner and the outside. With B3, black takes the corner. The sequence continues to B5, followed with W6 at W6 or b. The continuation after that depends on the surrounding situation.

[Diagram]
Taking the outside (B11 to B13 at a-b-c)  

The combination of B3 and B7 may be due to Shimamura Toshihiro in a 1950 Oteai game against Takagawa. This sequence occurs in the 1971 Honinbo Tournament book, with the attribution to him (but no game reference).

The idea is that White cannot now live in the corner. The stone B7 is not for taking.

[Diagram]
No life in the corner (B4 at black+circle, W7 captures, W11 at a, B12 at b)  

This diagram shows that white cannot take the black stones by playing W10 in the previous diagram at W1 here. After B12, the white corner group is dead.

[Diagram]
A modern variation, but why?  

A more modern variation (I see no occurences before 2010, but it has become the more usual move since then) is for black to play B5 immediately. White answer with W6 at W6, W8 or B9. There must be a reason for this move, but I don't see it. If white plays W6 here, the variation converts to the previous one, so my feeling is that black is only giving white extra options.

[Diagram]
Preparing to attack  

Playing B1 instead of a looks like a quiet, submissive move. But in this case, at least if there is a stone at black+circle or around that spot, looks are deceptive. Black is just avoiding any weaknesses in his position, so that he can all the more forcefully attack white with B3 and the following moves.

[Diagram]
White gets the corner  

If white plays W1, followed by B2, white will get the corner (see for an exception further down, however). White lives comfortably in the corner, but black gets outside strength in all directions.

[Diagram]
A small life  

If white does not want to provoke B6 and B8 in the previous diagram, he can also live with W5 here. Note that after W9, a is black's sente.

[Diagram]
Black plays hane  

If black blocks with B2, white usually reverts to W3. After W7, the aji of the white stones in the corner give his an advantage in the fight at the top by making any of the points marked x his sente.

[Diagram]
Tripod group  

White could also play W3 here, after which he lives by creating a tripod group. This is however more a joseki for books and amateurs. Professionals tend to play this way only when there is not enough room to live on the upper side.

[Diagram]
Under attack  

B2 is another book move that is more usual among amateurs than among professionals. The idea behind this move is that the white group is left out into the center, but there will be heavily attacked or even killed.

[Diagram]
Another attack  

In professional play, the more usual way to get a similar result would be B2 and B4 here. Again white cannot live in the corner, and is facing a tough fight in the center.


[3] Blocking inside

[Diagram]
Blocking from the inside  

B2 chooses to protect the corner. White forces once more with W3, then lightly jumps out with W5 or some such point. White could also play around W5 or even play tenuki immediately, satisfied with having W1 around for future use.

[Diagram]
Clamp  

Another continuation for White is the clamp at W3. In Strategic Concepts of Go Nagahara analyzes the result of the joseki in this diagram. By removing the stones at W1, B2, W3, and B4, Nagahara shows by tewari analysis that Black has played at B6 in answer to White's probe at W5 - an unfavorable exchange (in the position shown in the book).


[4] Pulling back

[Diagram]
Pulling back  

Pulling back with B2 is a common answer to W1 when Black wants to give White as little help settling his stone as possible. This leaves White with few forcing moves. If Black has a strong position in the middle of the upper side this can lead to a strong attack on W1. A standard response by White is a hane at W3. Black will then usually pincer at B4 (if he doesn't already have a strong stone in that area) or play on top at a. If the attack in this diagram is too powerful, white should play more lightly with a move around b instead of W3, keeping W3 for later use.


[5] The other pull-back

[Diagram]
Pulling back  

B2 has the same intention as a, giving white as little help as possible in settling his stone. White will usually jump out with a move like W3 (although sometimes W3 is played at B4 immediately), black's answer depends on the position on the top and exactly which move white has chosen. B4 is an important point for both. If white plays it, black has to answer at a, because giving white living stones at both the top and the corner is a clear loss for black. Still white is often not in a hurry to play it, hoping to get a chance to play immediately in the corner at a or b, so black might be able to play B4 even though for him it is gote.


2-4 Probe against a low corner enclosure last edited by 24.180.54.131 on March 27, 2018 - 18:35
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