Correct response to a joseki change.

Alguien · Post by **Alguien** » Sun Sep 16, 2012 11:52 pm

In a recent game, I found myself in this situation. Top right corner was black and he decided to omit D14.

I made a severe mistake at 8, but thinking about it later (and reviewing the position with the helpful people at the KGS teaching ladder) I'm not entirely sure of the best local answer to the "tenuki/pincer".

Click Here To Show Diagram Code: [go]$$Bc $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 2 . . . . . . . . . . . . . | $$ | . . b 1 . 4 . . . 5 . . . . . X . . . | $$ | . . 7 6 . . . . . . . . . . . . . . . | $$ | . . . a . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

My conclusions (after much help by Uberdude) are that the next move should be at a or b.

My fear is the following situation.

Click Here To Show Diagram Code: [go]$$Bc $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 2 . . . . . . . . . . . . . | $$ | . . . 1 9 4 . . . 5 . . . . . X . . . | $$ | . . 7 6 . 0 . . . . . . . . . . . . . | $$ | . . . 8 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Both white and black have cut points and a bad shape that should be exploitable, but my tries give a very large corner in exchange for the outside influence but with white ending in gote.

The problem is that the influence to the right isn't very effective, and giving sente to b allows him to reduce the influence along left wall.

I'm talking of a scenario like this:

Click Here To Show Diagram Code: [go]$$Bcm11 :b11: tenuki $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 7 3 . X O . . . . . . . . . . . . . | $$ | 9 4 2 X X O . . . X . . . . . X . . . | $$ | . 5 X O . O . . . . . . . . . . . . . | $$ | . 6 8 O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . 0 . . . . . . . . . . . . |[/go]

Or this (black continues)

Click Here To Show Diagram Code: [go]$$Bcm11 $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X O . . . . . . . . . . . . . | $$ | . . 1 X X O . . . X . . . . . X . . . | $$ | . . X O . O . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . 2 . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Is this the best white can do? Is this really bad for black? (taking into account he started diverging from joseki)

Is the tenuki/pincer at K16 actually ok in this situation?

EdLee · Post by **EdLee** » Mon Sep 17, 2012 1:43 am

Alguien wrote:Top right corner was black and he decided to omit at D14.
the best local answer to .
Is actually ok in this situation?

I'm a little confused about your

and

-- could you check to make sure you got the colors correct for move 5 --

or

?

Alguien wrote:I made a severe mistake at 8

I don't think your

is a mistake at all.

Here's one variation:

Click Here To Show Diagram Code: [go]$$B :b5: tenuki $$ ------------------- $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . 3 2 . . . $$ | . . 0 1 . 4 . . . $$ | . . 7 6 . . . . . $$ | . . 9 8 . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$Bm11 $$ ------------------- $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . 3 1 5 X O . . . $$ | 9 2 O X 4 O . . . $$ | . 7 X O . . . . . $$ | . 8 X O . . . . . $$ | . . 6 0 . . . . . $$ | . . . . . . . . .[/go]

Alguien · Post by **Alguien** » Mon Sep 17, 2012 1:47 am

EdLee wrote:
Alguien wrote:Top right corner was black and he decided to omit at D14.
the best local answer to .
Is actually ok in this situation?
I'm a little confused about your and -- could you check to make sure you got the colors correct for move 5 -- or ?

It had to be

everywhere

. I changed the corner color mid-post.

EdLee · Post by **EdLee** » Mon Sep 17, 2012 1:53 am

Alguien wrote:It had to be everywhere . I changed the corner color mid-post.

There is still a

in your third diagram:

Alguien wrote:
$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 6 2 . X O . . . . . . . . . . . . . |
$$ | 8 3 1 X X O . . . X . . . . . X . . . |
$$ | . 4 X O . O . . . . . . . . . . . . . |
$$ | . 5 7 O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . 9 . . . . . . . . . . . . |
Click Here To Show Diagram Code
[go]$$W $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 6 2 . X O . . . . . . . . . . . . . | $$ | 8 3 1 X X O . . . X . . . . . X . . . | $$ | . 4 X O . O . . . . . . . . . . . . . | $$ | . 5 7 O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . 9 . . . . . . . . . . . . |[/go]

Alguien · Post by **Alguien** » Mon Sep 17, 2012 1:55 am

EdLee wrote:don't think your is a mistake at all.

(My mistake was playing c14. What you see in the diagram is the result of my asking for help and later analysis.

Here's one variation:

Click Here To Show Diagram Code: [go]$$B :b5: tenuki $$ ------------------- $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . 3 2 . . . $$ | . . 0 1 . 4 . . . $$ | . . 7 6 . . . . . $$ | . . 9 8 . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

That

seems to give a worse result than e16. And it looks like it could be played after e16 anyway. However, in that case, b could play c16 instead of c14 (resulting in my last diagram).

EdLee · Post by **EdLee** » Mon Sep 17, 2012 1:58 am

Alguien wrote:That seems to give a worse result than e16...

Remember that

E16 is an empty triangle, and pushing W from behind.

Alguien · Post by **Alguien** » Mon Sep 17, 2012 2:01 am

EdLee wrote:There is still a in your third diagram:

I've referenced the tenuki by its position, as I don't know how to write numbers over 10.

EdLee · Post by **EdLee** » Mon Sep 17, 2012 3:08 am

Alguien wrote:as I don't know how to write numbers over 10.

Like this:

,

, ...,

,

.

Click Here To Show Diagram Code: [go]$$Bm11 $$ ------------------- $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . 3 1 5 X O . . . $$ | 9 2 O X 4 O . . . $$ | . 7 X O . . . . . $$ | . 8 X O . . . . . $$ | . . 6 0 . . . . . $$ | . . . . . . . . .[/go]

topazg · Post by **topazg** » Mon Sep 17, 2012 3:37 am

The empty triangle does look like it creates a better position for me - there are quite a few empty triangle responses in this corner shape I've seen (often when leading to a subsequent cut and messy fight). My gut feeling is that, if

in alguien's earlier diagram needs to pull back and can't block because of the cut, then it creates better eyeshape and still leaves a cutting point that White feels somewhat obliged to fix. If that _is_ the case, then it looks superior than Ed's version which leaves White in pristine shape.

Bill Spight · Post by **Bill Spight** » Mon Sep 17, 2012 4:09 am

Here are some variations, based on the Small Joseki Dictionary by Suzuki and Kitani. I include a couple of suggestions of my own.

OtakuViking · Post by **OtakuViking** » Mon Sep 17, 2012 4:12 am

This shape is the story of my go on tygem. I see it really often ^_^

SoDesuNe · Post by **SoDesuNe** » Mon Sep 17, 2012 4:21 am

My take : )

In my opinion the only "hard-to-cope-with" situation is this follow-up-play by Black.

Click Here To Show Diagram Code: [go]$$Bcm11 First Diagramme $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X O . . . . . . . a . . . . . | $$ | . . 1 X X O . . . X . . . . . X . . . | $$ | . . X O . O . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . b . . . 2 . . . . . . . . . . . . | $$ | . . . c . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Let's compare this to the "normal" Joseki.

Click Here To Show Diagram Code: [go]$$Bc Second Diagramme $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . x . . . . . . . . . . . . . . | $$ | . . c . 1 O . . . . . a . b . . . . . | $$ | . . . X . 2 . . . 4 . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 3 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . d . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

First of all, let's look at White.
White has obviously no territory in the first diagramme but is considerably strong at the outside. The resulting shape is also hard to attack. That makes me wonder if Black's K16 is not too close to White's thickness? White could possibly invade at 'a' if Black does not defend. And when Black defends White has Sente (huge in the opening).

White does not have Sente in the second diagramme and Black does not have to defend anything locally. And again, White hasn't surrounded territory with his shape. Black can poke with 'a' for example. The results in both diagrammes favour influence. Notice how White has a big follow-up in the second diagramme with 'b', which is coincidentally the same point at which White could attack in the first diagramme. This leads me to think, that Black's K16 would be better at O17 to counter White's thickness and that K16 is indeed to close to White's thickness.

So, to look at Black.
If I'm correct with my above reasoning, Black's K16 ends up being a burden. Of course it prevents a White extension but White does not need to extend after the exchanges against the corner. White's safe in the center. So, not only loses K16 it's usefulness since it does not keep White weak, it becomes considerably weak itself and needs to be defended, which loses the initiative Black would have otherwise (with the "normal" Joseki) kept.

Let's compare Black's corner-shape.
The first diagramme is obviously tremendously solid and White has no way of trying nasty things. But Black is also confined to its corner. Sure, Black can push from behind but this gives White an even more solid wall and when Black jumps to 'b', I think White can still jump ahead at 'c'. So Black is solid but lacks prospect.

Completely different in the second diagramme. Black's ahead of White has considerably more prossibilities to develop this group (he could expand at the side, he could possibly attack White when gets a stone around 'a' etc.) But, sure, this comes with a price. White has nice points at 'c' and 'd'. But White has to always pay attention to his upper group. If White plays 'c' carelessly, Black could just extend up at 'x', let White live in the corner and then approach with 'a' or something like that. Black will then dictate the flow. Carelessly playing 'd' can also result in an attack (free forcing moves) on the upper group.
So this shape is really flexible for Black, he has a lot of possibilities to react to changes on the board.

To put in a nutshell: I think the first diagramme lacks spirit. It greedily takes the corner but either loses Sente or gives White a nice attack. It does not give Black any follow-up, he cut away his possibilities and White will have the chance to play his game.

topazg · Post by **topazg** » Mon Sep 17, 2012 4:38 am

With Q16 in place for Black, I don't see either line as all that unreasonable. By choice, I don't like leaving White with C14 (in the pincer lines), and I think C13 for Black is big enough that White's going to take C14 fairly soon if Black doesn't get in straight away. But, with Q16, Black can reinforce at the top wide with something like O17 and it seems ok for Black. Black either has sente or C13, neither of which are small.

I very much doubt either sequence would be guilty of being the game losing move (/sequence).

Alguien · Post by **Alguien** » Mon Sep 17, 2012 5:32 am

Bill Spight wrote:Here are some variations, based on the Small Joseki Dictionary by Suzuki and Kitani. I include a couple of suggestions of my own.

Thank you very much for that post.

In case anyone's interested on how badly we lowly sdk play, this is how that corner noseki was really played:

I'll stop there to avoid eyes bleeding too much.

I lost after several blunders.

Dusk Eagle · Post by **Dusk Eagle** » Mon Sep 17, 2012 6:04 am

Hey Alguien,

Just as a rule of thumb, try to avoid playing moves like the one below (of course there are exceptions). The extra power you give black is far greater than the extra stability such a stone provides. When you want to play an extension when there's a pincer, the correct location is one space farther from the pincer ('a').

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X O . a 1 2 . . . . . X . . . | $$ | . . . X X O . . . X . . . . . , . . . | $$ | . . X O X . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

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Correct response to a joseki change.

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