Invading the four star points box formation - discussion
Keywords: Opening, MiddleGame, Strategy
Floris:
Therefore I usually find it good to first approach the upper right, and then invade, making Black overconcentrated: if he plays along, that is.
![[Diagram]](../../diagrams/48/a4896fbff473113473efaabf35f68c92.png) | Dia 1 |
The sequence up to is good for White, makes a and b miai for a base, and in this making Black overconcentrated or reducing his territory.
Actually, Black made a (small) mistake (not wrong in all situations) somewhere, can you spot it?[1]
Yes, the not-so-good move is , above it is better played at in the following diagram.[2]
![[Diagram]](../../diagrams/49/2f707819e04a3eff696503e23767a2a7.png) | Dia 1 |
Out of all the other pincers puts the most pressure on White. The continuation up to is most usual, except Black will have a huge advantage in the coming fight as White has two weak groups. Notice the black move at tengen is a ladder breaker here and without it is much less severe (makes the cut at impossible).
Andre Engels: I very much do not agree with most of what you are saying here.
![[Diagram]](../../diagrams/32/95d190848fd4b0101c5e87b3bd31d8d9.png) | Dia 1 |
in this diagram looks bad to me. Black happily takes the opportunity to strengthen herself with , then attacks White's shape with (looks better than a). Sure, White will live, but Black becomes thick. BobMcGuigan-- See Angle play after diagonal attachment
![[Diagram]](../../diagrams/3/92376deb034b21a745dccb38f4dc78bf.png) | Dia 2 (White 11 at a) |
In the diagram that you consider 'better', I have the feeling that is a serious overplay.
I don't agree that White is left with two weak groups - Black is so strong in this environment to start with, that White should have no qualms about sacrificing one of them. Here you see one possible continuation.
![[Diagram]](../../diagrams/43/cac92545c5bd569c0b4f3d7ff6be2dfd.png) | Dia 1 |
Here is another possibility. Black might seem to be doing well, but White a-Black b-White c, killing the corner is hanging above him, like the sword of Damocles. .
[1]
Charles Like Andre, I have difficulty accepting these statements.
In the four star points box formation, my database gives the diagonal attachment like this in 15 cases out of 15:
![[Diagram]](../../diagrams/52/39531e4f6f2430f5d168b74b0a3174b9.png) | Diagonal attachment |
So I doubt that is really a mistake.
Also, I don't like the angle play for White here except in a different context. See discussion at Angle play after diagonal attachment.
unkx80: A general comment:
![[Diagram]](../../diagrams/15/bb1e49bd53e875ac47b2caeea10e0eb0.png) | A general comment. |
For players who are uncomfortable playing at Black a and allow an invasion at White b, he or she can consider playing at or c instead. Then at a later move, Black can play at a if White has not already played in the vicinity.
![[Diagram]](../../diagrams/10/e425ea33f953b7ed664ab9e40b8c133b.png) | Dia 1 |
Yes White indeed lives, but tengen stone really doesn't do much at the moment and Black is fairly overconcentrated in the top right. I suppose a move at a would make it easier to make territory with the tengen stone but then White can take a remaining big point on the board.
![[Diagram]](../../diagrams/3/92376deb034b21a745dccb38f4dc78bf.png) | Dia 2 (White 11 at a) |
I cannot call this a good result for White. Black is whistling while solidifying tons of territory as White is fleeing for life.
![[Diagram]](../../diagrams/44/9f68806c3e3fd1933f3d8375285d3d42.png) | Dia 1 |
I think is a bit mild, maybe at a is better to put more pressure on White. Also, after the sequence you show up here, I think Black b is a very severe follow-up (this would have been even more severe if was at a, but then White wouldn't play ). Sure Black's corner isn't alive yet, but he should first worry about making profit from attacking the two white groups before worrying about the status of his corner.
Also, I don't think it is an overplay: it was taught to me by Guo Juan and I doubt she'd teach her students overplays :/[3]
Pro invasion
![[Diagram]](../../diagrams/46/c6bd26d63366b7831d0df65620126440.png) | Dia 1 |
I think for this reason pros tend to like the invasion at better instead of a.[4]
[2] Discussed at kosumitsuke joseki.
[3]
Charles You know, Floris, we can't just accept that Guo is your teacher, she tells you things, you tell us, and we have to agree!
[4]
Charles
![[Diagram]](../../diagrams/33/1079773424ec1f7411cc4cd45f1084e3.png) | How to develop? |
OK, maybe I now start to understand. Given this position, the pros just don't add the tengen stone (Black at the circled point).
The widest path here is , then to invade. Perhaps what Floris is telling us is an answer to a 'what if?' question. What if Black does make a four star points box formation? That's not so common in pro play - tengen isn't so easy to use. But without any examples for the 'pro invasion' diagram, what can one say?
If I can tentatively reconstruct the lesson:
Black's use of tengen here isn't favoured by pros. But amateurs often play it. If White enters a box formation that isn't really well constructed, maybe immediate life might be enough (showing why Black's strategy with tengen wasn't so good). Therefore Black must play a more aggressive way - the requirements of the position dictate it.
I'll accept that the angle play might be appropriate here, then. There is another way to play, also needing consideration. The general technique has been called digging in?,
Therefore, going back to the starting diagram, we could call here questionable.
![[Diagram]](../../diagrams/50/1d65077e2e353263eebcb56cfc6dc6c2.png) | Where this all starts |
It probably isn't the case that is the biggest point. Black must make sure this stone is used to fight.
White has played a strong group plan on the right side. This isn't a case of making Black over-concentrated, though.
I see that this position has occurred in a couple of pro games from China. In both cases Black played at a instead of .
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