BQM 398

    Keywords: Question

Here is a position presented in O Meien's NHK Lecture volume (Japanese), Develop Your Stones Meien Style (2002, ISBN4-14-016113-2). The question under discussion is the biggest move on the board, Black to play:

19x19 diagram  

The answer is B1, in the largest open side area, with this possible continuation.

19x19 diagram  

This B1 is also big, but not big enough because, according to O Meien, even if B gets the displayed sequence, ending with Ba after B10, W's left side and moyo is bigger than B's upper right corner and moyo.

19x19 diagram  

If B tries to get both moves in, starting with the top, the placement W4 could happen, with B ending up with an eyeless, attackable group.

So my question (finally!) is this:

19x19 diagram  

Even after the recommended B1 at the lower left, W could still play W2, threatening the same nasty placement at a. How should B counter this without looking like the third diagram and without letting W develop a position down the left side and catching B1 in a serious pincer attack? Or should B take the pincer attack, if it comes to that, and get his compensation by playing into the 3-3 point? Remember, B1 is supposed to be the biggest move on the board.
Thanks. --FredK

First attempt  

Jeff: My first attempt. By extending at B1, black simultaneously:

  • Strengthens black+circle
  • Attacks white+circle
  • Makes the placement at a much smaller

If white tries the placement...

Continuation (cont.)  

Now, white has a ko for life at best (or at least to the best of my reading). And white has to make the first threat. Unfortunately. it seems a minor loss if white loses this ko, but if black loses, he's left with two weak groups. Ouch!

MrTenuki (KGS 3k): I don't think the "ouch" comment really applies, because white has to make the first threat. Judging from the fact that this is the full board, I would ignore any threat as black.

19x19 diagram  

Herman Hiddema: Here's an idea. With the B3-W4 exchange, black defends against the placement while making white heavy. Then with B5, black denies white the possibility to make a base for his stones. After that, a and b are pretty much miai. If white defends the side by playing W6 at b, black will attack the heavy W2-W4 group with a. But if white connects those heavy stones by playing a himself, then black can play a double approach against the corner at b, which also attack the marked stone white+circle.

Jeff: Wow! I didn't see B3 at all, but it does seem to solidly prevent white x. Thanks for pointing that out, Herman!

FredK: This diagram looks nice -- thanks for your thoughts. Here's a further question. Suppose W decides to tenuki after B3 and play W4 at 5, making a pincer. This is probably a greedy overplay, but W has some strength along the bottom so W could probably stir up trouble. How should B respond, to keep things reasonably uncomplicated? Is the potential vulnerability of the two marked W stones, after a possible B play near b, still the deciding factor?

Herman Hiddema: Well, the first thing to keep in mind, is that the W2-B3 exchange doe not gain white anything locally. So if you're gonna play W4 at B5, you might as well play W2 at B5. That way, you can always choose what to do in the upper left corner later. Playing ther now is aji-keshi. Now on to your question. If white plays at the position of B5, that is a pincer of B1. black can then choose to jump out with a one point jump, or to take the corner with a move at 3-3. I personally would prefer to take the corner, but jumpin out also has a lot going for it (if after jump, white defends at b, you can then attack the pincer stone.

Andy Pierce: If black plays B1, then all black's stones on the left are low. The lower left corner is open, but white must be ok with that. Since white played the white+circle stones high, presumably for influence, it seems to me a logical continuation for white is the attachment at x. White moves at y don't look attractive since black can treat B1 lightly as a forcing move and still undermine the lower side effectively. Just my 5 kyu guess though.

BQM 398 last edited by on May 12, 2010 - 00:23
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Login / Prefs
Sensei's Library