BQM 496

    Keywords: Question

Table of contents Table of diagrams
Diagram 1
Block on the top
Block on the top-Game Continuation
Block on the top-Game even more continuation
Block on the left
Black tries to kill
Variation - white keima
Joseki continuation (without WC)
Diagram 1

Game position

Diagram 1  

Abydos1: I had this played against me in a 2 stone handicap game where I was black. After B1 white invaded at W2, then with B3 W4 there's the decision of which side to block. I played b leading to the next position:

Black blocks on the top

Block on the top  

Abydos1: This seemed better to me at the time since I though white would have a hard time dealing with B5 here even though black is somewhat overconcentrated on the top; after searching similar positions on Eidogo I found that most pros appeared to block at a in diagram 1, leading to a result similar to diagram 3 (in most cases there where a lot of other stones around though and black didn't usually have black+circle).

xela: Black is very overconcentrated at the top.

Abydos1: I already admitted black is overconcentrated here but B5 seems severe to me and I'd like to see some opinions on how white can best continue here. As I said below black+circle would seem to have a large impact on how this side gets played out and in my opinion the invasion at B5 seemed severe enough to counteract the overconcentration black suffers at the top.

Andy: I think you are incorrect in your assessment that B5 is severe. White is alive in the corner and white+circle is light, so what are you going to attack? White will either ignore B5 or press on the bottom corner and eventually eat B5 is my guess.

Abydos1: If white ignores B5 it seems black can seal the corner and/or take a high position on the top and be very comfortable on this side (granted, black played in both corners here first so we'd have to look at the whole board). Also, the point of B5 over a is that white has a harder time leaning on the bottom (or counterattacking).

Andy: Where does this "and/or" concept come from? The "and" part is impossible, since white isn't going to pass her turn. Since it's white's sente, white even gets to pick which of these two "or" options she wants, or if both are too small, she can play a bigger move elsewhere and still get a nice move here (whichever one black doesn't pick).

Block on the top-Game Continuation  

For reference here is the continuation that was played:

Abydos1: Black a follows; white's position quickly falls apart when white tries to resist.

  • Andy: That's white's fault for making white+circle heavy. I think white should be happy about living in the corner with black overconcentrated and tenuki with W2.
Block on the top-Game even more continuation  

tapir: Even this is not sooo bad for white, imo.

Abydos1: b and d seem like miai here but both look very large for black.

Black blocks on the left

Block on the left  

Abydos1: This to me seems better for white, black's stones seem very inefficient here; any of the thickness gained from the 3-3 invasion is offset by white's strong position on the side. I'm wanted to get some higher level opinions on the situation here, mainly concerning black's position in diagram 3 and how white should respond to B5 in diagram 2.

tapir: Black can close the upper side in sente (threatening the life of the corner). And presumably the white group is less strong and smaller than it looks. Later black can jump in at the 2nd line threatening to connect to B7 to destroy the eyeshape of it.

xela: This is a great result for black. The white group on the side still isn't settled: there's an invasion point at a.

Abydos1: According to [ext] eidogo this is somewhat joseki but without white+circle ("White may play this way when Black has a pincer at c. Otherwise, White would not prefer to crawl into such a small space.") and finishing with the black b-white+circle exchange. I can see that white doesn't have much territory here but the black stones still look very inefficient to me only serving to split white into two groups which are both practically alive now. B1 from diagram 1 also has a large effect on both results and if it wasn't in place I would've probably preferred to block this way; I was more specifically curious about the play while taking into account the bottom left corner.

tapir: Btw, I felt the same when seeing this and similar positions the first time. In the bottom left black played an approach to the white hoshi stone already further reducing white's strength. The main lesson I try to learn from that is not what is considered equal by professionals, but that you have to use weaknesses in your opponents position mercilessly. If white is allowed to make territory on the left edge without compensation than the whole exchange surely is to her favour.

ThorAvaTahr: I don't have a good feeling with a, I feel that d remains the vital point. However in any case, white's group is heavy and urgently needs reinforcement. A move at e takes away the base of the group.

Abydos1: b would be bigger here taking a high position on the top (assuming a good situation in the upper right) and forcing white to live overconcentrated on the side (or perhaps jump out to prevent black from sealing the group in. a would be premature, white can be happy with the influence gained for very little black territory on the side; same result with e (e looks weak to me with the two ogeimas on the bottom).


Black tries to kill  

Iago how about this then ? Black needs the ladder, but can white live after B a ? I think not...

ThorAvaTahr: Good point, seems white is overplaying unless he has some tactic to cut.

Abydos1: It could probably be assumed that white has the ladder since black has these two corners (in the actual game white had the ladder).

Variation - white keima  

Should White respond with W4 in place of extending? Black might play either b or c and white lives after d; the outside liberty at circle is vital to White's living lest the hane at a catch the two white stones in a shortage of liberties it seems.

Abydos1: Actually, after black c white extends to circle (see below).

Joseki continuation (without white+circle)  

Is this desirable for White? The corner is only slightly larger and Black has been strengthened considerably on the outside.

Abydos1: See the joseki page for more on this position (without white+circle).

Don't see where the joseki page addresses whether or not its good to strengthen Black on the outside by standing up with W2, losing a liberty and having to come back to W4. Black ends up with B5 in place defending the cutting point. Why encourage Black to fix this weakness?

Abydos1: Well it does point out that it isn't always best to jump into the 3-3 point early in the game but it can be beneficial if white is strong in the surrounding area. White has the option to cut before going back to live at W4.

Bob McGuigan: Here is an idea going back to the beginning. I think B1 in the first diagram above was a suboptimal move. If B1 had been played one space higher as here:

Diagram 1  

This B1 puts more pressure on the two white stones and would make many of the upper corner continuations shown above more effective.

Abydos1: Either white stone could be treated lightly so the extra pressure might not be the best idea. a has more effect on the corner and gives white less options for continuing in that direction from white+circle.

Tapir: It is important that your moves have a follow up. After a tournament I've seen Hwang In-seong commenting games, for all of us incl. the tournament winner he invariably said... look for moves with follow up, quite often we played a-type moves looking more secure whatever, while he proposed B1-type moves. It is not about pressure in the sense of proximity making pressure, but what it means for a later invasion at c, or allowing to destroy whites base through a simple slide..

Iago I agree with Bob McGuigan this is the key point. a is not a good move.

With 1, white is in real trouble after invading the upper corner. If black is interested in the bottom corner, a keima (below a) would be better imo.

This distinction between moves with a continuation and vague moves is probably the best lesson from this BQM.

Abydos1: Yes, a here is a weak compromise between applying pressure to white and securing the corner since it does neither particularly well. A quick search on [ext] eidogo shows each of B1, a, and b played once while [ext] has B1 played 80 times; a, 34 times; and b, 9 times. I'd be interested to see results from a search of a larger pro-game database.

BQM 496 last edited by Dieter on January 21, 2010 - 14:07
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