beginner joseki question

[otenki]

Hey guys,

I'm having a bit of an issue with a basic joseki.
I would never play 12 as white, instead I would just jump at k4 or something.
I do howhever think that 13,14 exchange is sente.

So whenever I play this joseki I skip the 11-12 exchange as black because I think that my opponent will ignore the atari.

I have the feeling I'm missing something, why are people playing this exchange, what is so great for black to play it and for white to reply ?

Thanks
Otenki

(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Otenki]
;B[dp]
;W[cn]
;B[dn]
;W[dm]
;B[en]
;W[cp]
;B[co]
;W[bo]
;B[do]
;W[bm]
;B[cq]
;W[bp]
;B[em]
;W[dl]
;B[jq])

[jts]

First, why would you even play c4 if you were planning to ignore the Atari? Second, w having the ability to make a base in the corner isn't small. Third, you may be missing that the connection preserves a cut which thins out blacks wall a bit.

I agree that saving c4 feels a little bit unnatural, but then, IMHO playing c4 also feels unnatural.

[skydyr]

C4 keeps black from claiming the entire corner. If you give it up to jump, it's the same as not having played it at all, except that black now gets a more solid position and the extra point. C3 for black claims some of the corner back in sente.

I think white can play k4 depending on the surrounding situation, but he will take a local loss to do it, and if black has a stone on the top left, white's main group could come under fairly strong attack because it's not yet settled. It's better to cede k4 to black and use sente to make something somewhere else in that case. If white's position at the top left is quite strong and supports this group well, then by all means, play to reduce the value of black's wall. In this case, black probably shouldn't have picked this joseki.

[Uberdude]

Why make the exchange as black? Because if you don't and white descends at c3, it is pretty much sente and black has to block at d3. That result is then a lot better for white (more territory and eyeshape for white, less territory and eyeshape for black) than if black plays the atari and white connects. It's double sente.

So why connect? Because it is very big for territory and eyeshape for both players again. If black gets to capture at b4 white's group doesn't have 2 eyes on the edge, and black gets a lot of territory and a very strong shape in the corner. Another very important point is that after connecting there is still a cut at d3: this is huge again both for territory and eyeshape* (black b3 vs white d3 is a 22 point difference, see if you can count it). As well as cutting, white can use peeping at that cut to help invade the lower side later. Also if white has connected at b4 then black's wall has no eyes and if he is not careful it can even get attacked later.

*Assuming the double hane tesuji doesn't work

[Bill Spight]

You do not have to save the C-04 stone. I have added a continuation and a variation.

(;AP[GOWrite:2.2.21]SZ[19]FF[4]GM[1]CA[UTF-8]ST[2]PB[Otenki]PW[ ]RU[Japanese]GN[ ]PM[0]KM[0.0]FG[259:]
;B[dp]
;W[cn]
;B[dn]
;W[dm]
;B[en]
;W[cp]
;B[co]
;W[bo]
;B[do]
;W[bm]
;B[cq]
(
;W[bp]C[*** See variation.]
;B[em]
;W[dl]
;B[jq]C[*** See later continuation for White.]
;W[dq]
;B[eq]
;W[dr]
;B[er]
;W[cr]
)
(
;W[em]
;B[bp]C[*** Also joseki.]
)

)

[kivi]

I agree that saving c4 feels a little bit unnatural, ...

To me saving c4 is so natural that at first I thought otenki meant another stone/move

You should realize after joseki there is a weakness left at d3, which w can cut directly or use somehow. If b extends a little further, then weakness helps invasion.

You do not have to save the C-04 stone. I have added a continuation and a variation.

e7 instead of saving atari is not joseki at all (locally b much better). That can make sense only in very special case.

[Bill Spight]

You do not have to save the C-04 stone. I have added a continuation and a variation.

e7 instead of saving atari is not joseki at all (locally b much better). That can make sense only in very special case.

Since when is in not joseki? My source is Suzuki-Kitani. Compare with the joseki below.

(;AP[GOWrite:2.2.21]CA[ISO8859-1]GM[1]SZ[19]ST[2]FF[4]PB[ ]PW[ ]GN[ ]PM[2]FG[259:]
;B[dp]
;W[cn]
;B[dn]
;W[dm]
;B[en]
;W[bo]
;B[co]
;W[bm]
;B[bp]
;W[em]
;B[fn]
)

[otenki]

Thanks for the explanation.
I understand it a lot better, actualy its quite easy why white would save the stone now that i see your comments.
Just one more thing... the cut at d3. I think it is not possible because white gets captured:

(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Otenki]
;B[dp]
;W[cn]
;B[dn]
;W[dm]
;B[en]
;W[cp]
;B[co]
;W[bo]
;B[do]
;W[bm]
;B[cq]
;W[bp]
;B[em]
;W[dl]
;B[jq]
;W[dq]
;B[eq]
;W[dr]
;B[cr]
;W[er]
;B[fr]
;W[fq]
;B[es]
;W[ep]
;B[ds]
;W[eq]
;B[gr])

Or am I missing something ?

Cheers,
Otenki

[Bill Spight]

Keep going. Can you capture White?

[EdLee]

Otenki,

Double approach -- completely different situation...

(;CA[utf-8]RU[Japanese]GM[1]FF[4]AP[CGoban:3]SZ[19]ST[2]KM[0]MULTIGOGM[0]
;B[dp];W[cn];B[pd];W[fq];B[dn];W[dm];B[en];W[cp];B[co];W[bo];B[do];W[bm];B[cq];W[bp]
LB[eq:a][em:b][dl:c]C[Was it Go Seigen who came up with (a) now, instead of the (b)-(c) exchange first ?]
;B[em];W[dl];B[jq];W[dq];B[eq];W[dr])

[Uberdude]

Otenki: well done for finding that double hane tesuji. However, as Bill has hinted white is not actually captured. But if there were some extra black stones in this area, say k5 and h6, then this sequence may well work.

[otenki]

Thanks for pointing out my mistake Bill & Uberdude, indeed if i read deeper then in this case it does not work.

Edlee, thanks for giving that variation, looks very anoying for black though (although this is just my perception i guess). Going to give it a try just for fun & experience

Cheers,
Otenki

[kivi]

My source is Suzuki-Kitani.

Can you post that game.

Compare with the joseki below.

Previous one is as if you play this one, and then white plays c4 self atari (and black captures) --- not that I care 2 point loss, but the peep (w c3) is gone.

On the flip side black f6 is not there now, but I cry more for the c4-c3 exchange than care for f6.

[jts]

My source is Suzuki-Kitani.

Can you post that game.

Suzuki-Kitani is a joseki dictionary, no?

http://senseis.xmp.net/?DictionariesPage

[kivi]

My source is Suzuki-Kitani.

Can you post that game.

Suzuki-Kitani is a joseki dictionary, no?

http://senseis.xmp.net/?DictionariesPage

ah, I see. Then can Bill or somebody who has the book post what it says about that variation?