4-4 point low approach attach-block joseki
After exchanging for
, White is left with two cutting points. Common ways to handle this situation are a emphasising outside influence and b emphasising side territory. c is seen when White is already strong along the side to build a framework.
White has outside influence, Black considerable territory. Black can aim at a later to start an endgame ko, i.e. White can't expect to make much territory along the edge.
After Black can only defend at
and can't block at a. If Black blocks, White can play at
itself, taking the corner one way or another.
When White is strong on the upper side and does not like to concede a large corner as after a or being kept low as is likely after b is sometimes seen in professional games.
- See attach-block for the fundamental shape here.
- BQM370, BQM483
Not playing the atari?
A first interesting point about this joseki concerns . Can White omit this play in order to leave a weakness at the 3-3 point in the corner?
That idea is really in the realm of handicap go: playing the atari is undoubtedly the honte. There is an example from a quickplay game Cho Chikun-Kato Masao 1990-09-09, as here. After Black made strong shape with
, and White invaded at once with
, making miai of a and b.
In general this would be considered a thin way for White to play.
This Chinese classical joseki frequently occurs in old Chinese games when the marked stone approaches hoshi only after the two stones at the right have been played. Instead of , white a black b might be possible. The overall aim here is probably to settle white quickly.
Discussion
Am I correct in thinking that the choice of depends greatly on the situation along the top side of the board?
and
are in a good position to exploit a play
at the circled point. However, leaving aside the objection that White should have made an approach on the open side, if Black already has a stone in the vicinity of the marked point, would White not be better advised to play at a and seek influence in the centre, or is it simply the case that under those circumstances this is not joseki in the sense of an equitable result being attained?
I agree with you that in that case White a rather than appears to be the correct joseki. In fact, looking at pro games, I find that
is not a very common move: If White wants to make territory, White b is more common; if White goes for influence or thickness, a is. - Andre Engels
In Japan three years ago, I heard Tokimoto Hajime comment about this; saying that amateur players, who like the move at a, may run short of territory. That is, the pro attitude is rather more territorial here.
More variations can be added: I posted this new page to split it from the attach-block shape page. -- Charles Matthews
The pro attitude seems to be different in their own games as compared to their comments on amateur moves. -- Tapir