Extend or Pincer
Miz: Interesting topic. But nothing here so far, so I'll make up some examples. I hope more people will comment.
In this position, a White pincer is also an extension from the left side wall, so it seems better than just extending. a would be the natural extension. b would be a more severe pincer. But what kind of joseki would follow? Is c a good compromise, accomplishing both objectives, or is it "neither here nor there"? How about high pincers d and e?
- DaveSigaty: Here White has played the solid (heavy) connection at the marked stone and followed it up with a tenuki. This is not a very reasonable progression. In reply Black has played an approach against the strong, flexible stone at hoshi in the upper right instead of immediately trying to take advantage of White's previous play by attacking the upper left. This is also questionable :-) White's general aim here should be to repair the earlier failure to settle her stones on the upper side and to prevent Black from developing his approach stone in a sensible way. There is nothing fundamentally wrong with an approach move in the upper right. White can not expect to punish it too any great extent. The three white stones in the upper left are fairly far away and are themselves a thick but slow shape. I think this is an appropriate starting point for evaluating White's choices.
Kirk: Option b seems good if Black takes the corner. White jumps out and makes a nice framework at the top. It is a bit loose, but Black is not likely to invade as it would create a heavy burden.
- Dave I also think that the marked stone is out of balance. On the other hand if White holds back to p, I doubt that she is gaining enough on the upper side to compensate for Black's two corners. Black can look forward to playing a cap himself at the marked stone. I think this shows that the one-space pincer is too aggressive. It leaves too large a gap to the left. White can not afford to use two stones to span this gap, the stones will inevitably be over-concentrated.
Kirk: ...but if he jumps out, then I think Black gets the better of it. White is pushed down.
Charles Matthews White has played a joseki blindly here.
White ought to assess this variation before playing the marked stone as pincer. If it isn't good, White's pincer at c may be a better idea. (There is just a main variation at 4-4 point one-space low pincer, one-point jump; first of all there is a ladder question to consider.)
Kirk: This pincer looks pretty good. Perhaps Black's best bet is to cap. This exchange looks even to me, although White may be a bit unsatisfied since the sequence is Black's endgame privilege.
- Dave White should be very unsatisfied here. She has gotten virtually nothing in exchange for the upper left. On the upper right, her position is still wide open at both a and b.
Kirk: Black can settle himself easily, so it is hard to see the value here.
Kirk: Okay, the simple move at a in the original figure... Black has a lot of options since this pincer doesn't exert much pressure. The endgame concerns from above are also an issue here.
- Dave This pincer fits the situation. It is the traditional 3-space extension for a 2-stone wall on the left. At the same time it is a pincer on Black's approach stone, preventing the equally traditional 2-space extension by Black. Thus it kills two birds with one stone :-) There is a question whether White would be better off with a high move at a or not. Remembering that White tenuki'd once in arriving at the starting position, presumably she will be satisfied to achieve a reasonable result here in sente and turn away to that other part of the board where she has previously invested her extra move.
Kirk: All in all, I would probably play the one-space low pincer. It is severe, which means White stays in control. But isn't there another joseki after Black 1? Ishida gives no options. I can't believe nothing else works. What about 2-4? Is this feasible if White has a position in the lower right?
Kirk: Some-dan, please stop me before I make a fool of myself...
What if we reverse the colors on the left side? Is a pincer good now? a would clearly be a nice point for Black, so perhaps White should deny it to Black, by playing there first?
KarlKnechtel: If friendly stones nearby make a pincer a better idea, especially as a wall, presumably hostile stones nearby make it a worse idea?
Miz: You mean a white move at b now? I'm not sure if it should be called pincer at all, when the marked stone is in place. Perhaps it is playable, but it certainly isn't clear to me if it is any good. So I would simply extend along the right side.