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 Post subject: Joseki variation
Post #1 Posted: Sun Nov 20, 2016 1:46 pm 
Dies with sente

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In my recent Tygem games, I've come across an interesting variation in a joseki that I was hoping to get opinions on.
Click Here To Show Diagram Code
[go]$$Bc A modern variation
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . 6 a . . . . .
$$ | . 8 X , O b . 1 .
$$ | . . . . 3 4 . . .
$$ | . . 7 . 5 . . . .
$$ | . . . 2 . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

I understood the above ( :w6: in particular) to be a modern variation of the above joseki. The usual continuation I've seen in professional games is to cut at either A or B, with the result being that White eventually settles in the corner and Black gets some south-facing influence.

However, in my recent games, I've instead seen my opponents invariably playing the marked stone.
Click Here To Show Diagram Code
[go]$$Bc Diagram 2
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . a 6 b c . . . .
$$ | . 8 X , O d . 1 .
$$ | . . B . 3 4 . . .
$$ | . . 7 . 5 . . . .
$$ | . . . 2 . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

The fact that the response has been so uniform makes me think there's a lecture or something discussing it somewhere? In any case, I've been pondering White's best response, considering A, B or C. After either A or B, Black likely cuts at D, and there doesn't seem to be a good way of capturing the cutting stone, so Black gets excellent thickness (although White does get sente). This makes me think C is the right answer, but I'm not sure about the best continuation then. If White insists on capturing :b2:, then it seems Black will always get the cut.
Click Here To Show Diagram Code
[go]$$Wc Diagram 3
$$ ------------------
$$ | . . . . . . . . .
$$ | . 3 5 9 . . . . .
$$ | 7 2 O 4 1 . . . .
$$ | . O X 8 O 0 . X .
$$ | . 6 X . X O . . .
$$ | . . X . X . . . .
$$ | . . . O . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


So that makes me think that White shouldn't insist on capturing :b2: immediately:
Click Here To Show Diagram Code
[go]$$Wc Diagram 4
$$ ------------------
$$ | . . . . . . . . .
$$ | . 3 5 . . . . . .
$$ | . 2 O 4 1 . . . .
$$ | . O X . O . 7 X .
$$ | . 6 X . X O . . .
$$ | . . X . X . . . .
$$ | . . . O . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

This begins to look a lot like the results that are expected with the older version of the joseki. But here, :b6: looks slow/questionable, and I'm really a bit lost. What am I missing?

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 Post subject: Re: Joseki variation
Post #2 Posted: Sun Nov 20, 2016 2:32 pm 
Honinbo

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I am always confused about what is even in this position, but I just want to bring up the possibility of pushing once

Click Here To Show Diagram Code
[go]$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . a 6 b c . . . .
$$ | . 8 X , O d . 1 .
$$ | . . 9 . 3 4 . . .
$$ | . . 7 . 5 0 . . .
$$ | . . . 2 e . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


Maybe black will resist with something like 'b', but it might be nice to cover with 'e' as white, even if black gets the corner. So if white's push is sente for black to play 'e', it opens up many options, since 'b', etc., might be easier for white to play since black has a harder time cutting at 'd', now.

No idea if it's even, but at least it's something to think about.

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 Post subject: Re: Joseki variation
Post #3 Posted: Sun Nov 20, 2016 4:10 pm 
Oza

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It is listed in Josekipedia. Up to the hane is joseki. The connection is listed as "Question", which I assume means it has not been analyzed enough to know. But to me it looks submissive.

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 Post subject: Re: Joseki variation
Post #4 Posted: Mon Nov 21, 2016 4:00 am 
Judan

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Interesting question; I don't know the answer but here's how I'd approach it:

First take a look at normal joseki (and not) moves. So the idea of 8 is if black blocks immediately (a mistake) white can improve on an older joseki:

Click Here To Show Diagram Code
[go]$$Wcm8 dia. 1: Joseki mistake
$$ ------------------
$$ | . . . . . . . . .
$$ | . b . . . . . . .
$$ | . a O . . 5 . . .
$$ | . 1 X 3 O . . X .
$$ | . 2 4 . X O . . .
$$ | . . X . X . . . .
$$ | . . . O . . . . .
$$ | . . . . . . . . .
$$ | . . c . . . . . .[/go]


The exchange of 8 for 9 is good for white because now after black's capture at a white b is atari and white could then tenuki (probably) or defend (usually a bit slow). However black 9 is not totally useless, for example it means the jump to c is connected (I used this on move 45 of my Gold Cup game here viewtopic.php?p=210292#p210292). Compare this to the old joseki below, now if black a white can't block with atari but can only fall back to b which feels slow, or tenuki but then black's follow-up is bigger (if white connects the atari black can tenuki, but in first diagram if he does so then white can capture one stone which is quite big points and eyes).

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


So one joseki after the hane is for black to cut because at this moment white can only fall back so it's a good exchange (in dia.1 once white defends the cut in good shape it's self atari!) and although black sacrifices it the aji is useful for build the outside thickness). So white saves the outside stone and the corner is still up for grabs.
Click Here To Show Diagram Code
[go]$$Bcm9 dia. 3: joseki
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . O . 2 . . . .
$$ | . O X 4 O 1 6 X .
$$ | . 3 5 . X O . 7 .
$$ | . . X . X . . . .
$$ | . . . O . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


Another is where black cuts off the outside stone and white gets the corner. The outside stone still has significant aji and you quite often see pro games where white persuades black to add a netting move to reduce the outside. Worth noting a is sente, and black is open on the side at b. I don't seem to see this one so much these days, maybe they think it's locally good for white (and white doesn't do the corner attach of 6 if the outside is good for black).
Click Here To Show Diagram Code
[go]$$Bcm9 dia. 4: another joseki
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . a . . .
$$ | . 4 O 1 6 7 . . .
$$ | . O X 2 O 5 . X .
$$ | . b 3 . X O . . .
$$ | . . X . X . . . .
$$ | . . . O . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


So based on the above joseki results, white losing the outside stone is not the end of the world if you get the corner. So here's a simple way to answer that solid connection. So how would I judge this? White has a bigger territory than dia 5 and can even slide at a later. However there's no connection at b so you can't monkey jump or use moves like c as easily. Also black 13 means it's a lot harder to run out the cutting stone later, but it does still have aji. So my feeling is this is probably better for white than the joseki of dia 4.
Click Here To Show Diagram Code
[go]$$Bcm9 dia 5: simple way
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . a .
$$ | . b O 2 . 4 . . .
$$ | . O X , O 3 5 X .
$$ | . . 1 . X O . . .
$$ | . . X . X . . . .
$$ | . c . O . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


There is of course the question of if white can play 12 as atari at 13 but unless white can get that push Kirby showed in sente (which you probably can't) that looks doubtful.

Also I checked pro games for similar positions. Sometimes black crosscuts and you get white taking the corner and black the outside, but again white gets a result similar to dia. 4 and this solid connection result looks worse for black than those: http://ps.waltheri.net/database/game/67827/.

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 Post subject: Re: Joseki variation
Post #5 Posted: Mon Nov 21, 2016 7:13 pm 
Dies with sente

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Uberdude wrote:
So based on the above joseki results, white losing the outside stone is not the end of the world if you get the corner. So here's a simple way to answer that solid connection. So how would I judge this? White has a bigger territory than dia 5 and can even slide at a later. However there's no connection at b so you can't monkey jump or use moves like c as easily. Also black 13 means it's a lot harder to run out the cutting stone later, but it does still have aji. So my feeling is this is probably better for white than the joseki of dia 4.
Click Here To Show Diagram Code
[go]$$Bcm9 dia 5: simple way
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . a .
$$ | . b O 2 . 4 . . .
$$ | . O X , O 3 5 X .
$$ | . . 1 . X O . . .
$$ | . . X . X . . . .
$$ | . c . O . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]



This was actually what I ended up choosing under the time pressure of the game. In the context of the game, it felt unsatisfying because Black's influence was particularly useful, but in isolation I think I agree that White at least hasn't lost anything in this variation. In addition, just looking at the final result, all of White's stones make sense from a shape perspective, but H16 seems a bit odd for Black.

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 Post subject: Re: Joseki variation
Post #6 Posted: Tue Nov 22, 2016 3:17 am 
Judan

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studying wrote:
This was actually what I ended up choosing under the time pressure of the game. In the context of the game, it felt unsatisfying because Black's influence was particularly useful, but in isolation I think I agree that White at least hasn't lost anything in this variation. In addition, just looking at the final result, all of White's stones make sense from a shape perspective, but H16 seems a bit odd for Black.


If you don't like black getting the outside then I think the 3-3 corner attachment should be the bump as you keep centre access if black answers with the table shape (though there is scope for variation with the block or pull back). Then again if black really wants the centre maybe he should choose this one earlier:

Click Here To Show Diagram Code
[go]$$Bc Black wants thickness
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . X , O . . 1 .
$$ | . . . . . . . . .
$$ | . . . . 3 . . . .
$$ | . . . 2 . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

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