BQM 497

    Keywords: Question

ThorAvaTahr: The diagrams shows a very popular, modern fuseki. The idea about the tsuke underneath the shimari is to prevent white from being closed in. Although black's shimari becomes solid territory, white's group is more secure.

Modern fuseki
[thumbnail diagram] [thumbnail diagram]

Andy: Can someone please supply winning percentages with this fuseki when played by the pros? I see this quite frequently on KGS but offhand it doesn't seem that great for white. Black has two unassailable good-size corners and white's thickness is encroached on both sides by black and it is black's turn. In a related question, where does black usually play next after this formation is completed?

ThorAvaTahr: Interestingly many amateurs share your feeling. However, remember that white has komi. It is relevant, because typically black's plan is to use his starting advantage to make a large framework, in which he generates synergy from his starting stone. That plan is counteracted by white after this fuseki. Also note that black pushes from behind on the second line three times!!!

To answer your question, in a quick database search I found 56 games where the pattern at the left side was played 32 of these where won by white. The games inluded a wide variety of players, no player showed up more than two times in the list.

In this particular fuseki (with the white stones on the right placed as they show in the diagram) black usually plays 'a'. In the database search in 10 out of 13 games black played 'a', resulting in 5 wins. 'b' (2 games) and 'c' (1 game) show up as well but black lost all of these games.

Andy: If Black pushes from behind three times, does that mean Black is unimpressed with White's thickness?

kb: B8 does a little to mitigate White's thickness, but the main purpose behind B12 is to deny White a sente block there, which is big.

[Diagram]
Black's play without the third push  

ThorAvaTahr: Instead of diagram 2 my opponent played as in this diagram. In my limited professional database (only 45k out of 60k games) I found 90 hits on the fuseki, but noone played B7 as in this diagram. Therefore, I expect that this line is inferior. My question is, how can white profit from B7? Any ideas or comments?

[Diagram]
White blocking directly  

ThorAvaTahr: One idea is to play as in this diagram.

Tapir: Isn't white overconcentrated with b-e sequence later?

kb: See the analysis below why White at a before W1 is better. However, this is still playable, but with W5 one line lower (good shape both directions).


kb: I got the opportunity to study this exact fuseki in China in 2008.

[Diagram]
Diagram 2 Moves 11 to 20  

kb: The reason why Black makes the B7-W8 exchange is to make a White block on the right gote; otherwise B7 would be bad because it is pushing from behind and on the second line. (Normally, a second push on the second line is to avoid the block becoming sente, but because there is already a cutting stone a third push is needed).

Directly playing at B9 is not good.

[Diagram]
White probe  

kb: W1 is normally a probe in this position (with the black+circle/white+circle exchange); Black responds with a-c or tenuki (which is probably not good in the opening).

  • Ba is most frequent; White gains a little more security with the aji of the cutting stone.
  • Bb takes more influence at the cost of Wc becoming sente, since now Black must answer Wd with Be.
  • Bc has been played once but White gains a lot of influence in the center and a rock-solid group.
[Diagram]
Diagram 2a: White utilizes white+circle  

kb: However, in this case, W1 must be answered locally by a; otherwise White can capture the black+circle stones. Therefore you could play W1-B4 here; Black has been pushed around. (If you play W3 first, Black replies with B4; then W1 can be answered at b.)

ThorAvaTahr: Thank you for your excellent description of the theory behind the fuseki. I agree completely. And as I mentioned earlier, I would like to exchange W1 for B2 before blocking. After that I have a satisfactory result. However, my fear is that black will answer W1 with B3. After which it becomes difficult to get a good result. Therefore I am afraid I am forced to block immediately and give up the W1/B2 exchange.

[Diagram]
White after B2  

kb: First of all, I wouldn't call it a bad result. Actually, it is good for White!

[Diagram]
Actually, good for White  

kb: This looks like a little better for White. White got W3 in sente, has a more secure group than the joseki and has good follow-up moves, e.g. a and b. Remember, Black got three moves on the right first!

ThorAvaTahr: Hmm, looks interesting indeed. I'll have to think about it. Perhaps 'c' would be more appropriate than W7 here?

  • kb: I don't think so, because you should play thickly when you have a strong group nearby; allowing Black two peeps means it is less likely White will be able to develop the side efficiently. Black has little business invading the side after the solid connection because both groups are so strong.
[Diagram]
Transpose back to joseki  

kb: Nevertheless, if you don't like it, you can just respond like this, which transposes back to joseki:

ThorAvaTahr: No, I do not want to revert, I think black made a mistake and I am greedy ;)


[Diagram]
Black ignores the probe  

kb: By the way, I have had one opponent ignore the probe and cut at the lower right. My teacher advised me to ignore him too ;)

%%

[Diagram]
Pull back  

Dieter: And I guess that answering on the outside with B1, allowing White to return to the classical joseki, leaving a behind, is too passive for Black?

kb: Absolutely. Black trading b for c isn't good, because White still has a, therefore later White can play one point above b and Black is stuck.

In another light, tewari tells us that if W2-W4 is played first, then Black will never answer white+circle with B1 because the outside is no longer important.


BQM 497 last edited by Dieter on January 21, 2010 - 14:07
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