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Aji in a star point 2 space low pincer
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Author:  peppernut [ Sun Mar 24, 2013 12:37 am ]
Post subject:  Aji in a star point 2 space low pincer
In a quick time control game I had an opponent handle the aji in a star point 2-space low pincer oddly. Here's the rough position that arose:

Click Here To Show Diagram Code
[go]$$w
$$ ------------------------
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . O O O . O O . . . .
$$ | . O X X X X X . . X .
$$ | . X X . . . . . . . .
$$ | . . Q . a . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . X . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . b . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . O . . . . . . .
$$ | . . . . . O . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ -----------------------[/go]


Basically it looks like instead of killing the aji with an attachement on the marked stone, black pushes on the top.

A 1 point jump to a is often mentioned as a way to use the aji. Logically black's pushing works against this somewhat.

However I got the side extension 1 space below the pincer. In a 1-point pincer this is enough to connect under to the pincered stone (helpful is that the 2. line descent is sente).

How how to use the aji here? Is there a connection to the marked stone anymore? Or maybe we can just jump at 'a' straight away? If there's nothing favorable locally yet, it would instead make sense to build up the side with a move like b, and if black kills the stone we keep sente.
Author:  golem7 [ Sun Mar 24, 2013 2:18 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
When black already has defended by pushing up, a is pretty much useless, as you are 1 move behind and your stones are much to close to blacks thickness and will get attacked severely. I'd say the most natural move in this position is the knights move which grows your area while reducing blacks and preparing further reduction with b. One more thing to keep in mind is that black can double hane starting at c to close off the top side. If this is especially bad for you (depends on situation on top right that we can't see) you should nobi at c. But just from the information you provided I like the knights move. After that, black's position looks pretty inefficient.

Click Here To Show Diagram Code
[go]$$w
$$ ------------------------
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . O O O . O O c . . .
$$ | . O X X X X X . . X .
$$ | . X X . . . . . . . .
$$ | . . Q . a . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . b . . . . . . .
$$ | . . X . . . . . . . .
$$ | . . . . W . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . O . . . . . . .
$$ | . . . . . O . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ -----------------------[/go]
Author:  cdybeijing [ Sun Mar 24, 2013 3:16 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
It's important to note that black's two pushing moves are typically aji keshi, as the opportunity to play "c" in sente is lost.
Author:  EdLee [ Sun Mar 24, 2013 3:26 am ]
Post subject: 
peppernut wrote:
Here's the rough position that arose:
( my emphasis on rough. ) Also important to note that sometimes every single stone matters.
We need to look at the exact board, locally and globally, to start to analyze the position.
Author:  Uberdude [ Sun Mar 24, 2013 6:27 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
You've already used the aji of the approach stone to make territory on the top side and you want more?! As others said just playing from the outside below or nobi on top is plenty. Your question seems to reveal a greedy attitude that you don't wish black to make 10 points with his wall whilst you make 15 points above and 30 points below. Does that really sound like a bad deal for you?
Author:  peppernut [ Mon Mar 25, 2013 12:18 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
Uberdude wrote:
You've already used the aji of the approach stone to make territory on the top side and you want more?! As others said just playing from the outside below or nobi on top is plenty. Your question seems to reveal a greedy attitude that you don't wish black to make 15 points with his wall whilst you make 15 points above and 30 points below. Does that really sound like a bad deal for you?


You're right, I do have a greedy attitude and it's coming through (I'm working on it). I still want to understand what's going on though!

I started with the assumption that in the two-space low pincer, Black usually ends by capping the pincered stone to kill the aji. Probably because there's a lot of aji.

When Black pushes, it's not a move black wants to make. Aji-keshi. It's sente though, so in the opening if Black makes this exchange and kills the aji of the pincered stone, is it a fair trade? Since this isn't played, I am guessing the answer is 'no', but honestly I don't really understand.

You said I can play from the outside below, which I did and Black did not respond. Does this move help the marked stone? Enough so that there's a way to use it right away? Because if not then Black's push on top doesn't seem so bad at all.

Thanks for your criticism. If I learn just to see the points above and below, maybe these questions aren't really so important.

EdLee wrote:
Also important to note that sometimes every single stone matters.
We need to look at the exact board, locally and globally, to start to analyze the position.


Sorry -- I needed to find a windows computer to replay the game. Here's the actual position. It was indeed a little different.

Click Here To Show Diagram Code
[go]$$ White to play
$$ ----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O O . O O . . . . . . . . . . . . |
$$ | . O X X X X X . . X . . . X . X X . . |
$$ | . X X . . . . . . . . . . . . . O . . |
$$ | . . O . . . . . . . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . O . . . . . . O . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . X . . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


At this point the right side and lower left corner look bigger, but I am starting to eye the
Author:  Bill Spight [ Mon Mar 25, 2013 1:46 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
Click Here To Show Diagram Code
[go]$$W Hane
$$ ------------------------
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . O O O . O O . . . .
$$ | . O X X X X X 1 3 5 .
$$ | . X X . . . . 2 4 . .
$$ | . . W . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . X . . . . . . . .
$$ | . . . , . . . . . . .[/go]


Normally at this point White plays the hane at :w1:, followed by :b2: - :w5:. This is good for White, as a rule.

However, White cannot play this way because there is a Black stone at 5.

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


So with the :bc: stone in place, White just extends with :w1:. The fact that White remains low and Black is very thick makes this line playable for Black. The usual follow-up is :b2:.

What to do about the :wc: stone? It is not unusual to have an orphan stone or two on the board. What you usually do not do is to run with it (or them). In this situation, you look to reduce the Black framework. The threat to connect to :wc: increases the value of the reduction, and affects the tactics, but proceed normally. Consider the :wc: stone as almost sacrificed.

In the actual game, the fact that Black has a territorial framework on the right half of the top side makes :w1: very good. White now threatens to slide to "a" or perhaps make a deeper incursion. :)
Author:  SmoothOper [ Mon Mar 25, 2013 7:48 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
Uberdude wrote:
You've already used the aji of the approach stone to make territory on the top side and you want more?! As others said just playing from the outside below or nobi on top is plenty. Your question seems to reveal a greedy attitude that you don't wish black to make 10 points with his wall whilst you make 15 points above and 30 points below. Does that really sound like a bad deal for you?



I don't think the bottom corner is thirty points. Since there are number of invasions that would not only erase the points there but also threaten the 10-3 group against that big wall.
Author:  Uberdude [ Mon Mar 25, 2013 7:48 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
peppernut wrote:
When Black pushes, it's not a move black wants to make. Aji-keshi. It's sente though, so in the opening if Black makes this exchange and kills the aji of the pincered stone, is it a fair trade? Since this isn't played, I am guessing the answer is 'no', but honestly I don't really understand.

You said I can play from the outside below, which I did and Black did not respond. Does this move help the marked stone? Enough so that there's a way to use it right away? Because if not then Black's push on top doesn't seem so bad at all.


You are under the assumption that black's pushing at the top is a bad move? That is not true. as Bill said, having k16 in place makes a big difference and makes this a perfectly plausible local continuation with these 4-4 pincer joseki shapes. In fact it's generally better than the knight's move as it is thicker. Black gives white territory on the top in exchange for a thick wall. It doesn't totally kill the aji of the pincered stone, but significantly subdues it. "Is it a fair trade?" Too hard to say, that is a very subtle whole board judgement question. "Since this isn't played". Wrong, it is.

Example #1 is a game I remember from the EGC in 2011 where Catalin made these thick pushes (move 38). This builds a nice wall and connects to q10. If he didn't play them then black q6 would be too painful.



Example #2 is one example I found in GoGod as Bill's "The usual follow-up is :b2:" with the knight's move/kosumi surprised me as my instinct is the thick block as in the game below. GoGoD says this thick block is actually the usual move by 7 hits to 4.

http://www.go4go.net/go/games/sgfview/428

Blocking the top side in that game is rather unusual with the san-ren-sei on the right side as white gets to undermine the q10 stone. Again black immediately makes the thick pushes to connect up to q10 and transfer the moyo to the top side. Any other move would be bad as it would allow white q14 which would simultaneously isolate q10 and come into the top side moyo.
Author:  Uberdude [ Mon Mar 25, 2013 7:54 am ]
Post subject:  Re: Aji in a star point 2 space low pincer
SmoothOper wrote:
Uberdude wrote:
You've already used the aji of the approach stone to make territory on the top side and you want more?! As others said just playing from the outside below or nobi on top is plenty. Your question seems to reveal a greedy attitude that you don't wish black to make 10 points with his wall whilst you make 15 points above and 30 points below. Does that really sound like a bad deal for you?



I don't think the bottom corner is thirty points. Since there are number of invasions that would not only erase the points there but also threaten the 10-3 group against that big wall.


Indeed not, I was perhaps exaggerating a little for dramatic effect. But neither is black's area a solid 10/15 points either. If black does make it ~15 like so, then white does get ~30 points below:

Click Here To Show Diagram Code
[go]$$W
$$ ------------------------
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . O O O . O O . . . .
$$ | . O X X X X X . . X .
$$ | . X X . . . . . . . .
$$ | . . Q . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . 2 . . . . . .
$$ | . . X . . . . . . . .
$$ | . . . . 1 . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . 3 . . . . . . . .
$$ | . . . O . . . . . . .
$$ | . . . . . O . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ -----------------------[/go]


EDIT: I thought that board looked a bit funny (W's corner too tight given checking extension to 2 space pincer) and it is: it's 18 lines tall!
Author:  Bill Spight [ Mon Mar 25, 2013 12:23 pm ]
Post subject:  Re: Aji in a star point 2 space low pincer
Click Here To Show Diagram Code
[go]$$W
$$ ----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O O . O O 1 . . . . . . . . . . . |
$$ | . O X X X X X . . B . . . X . X X . . |
$$ | . X X . . . . . 2 . . . . . . . O . . |
$$ | . . O . . . . . . . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . O . . . . . . O . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . X . . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


It is true that I did not consult a database when I said that :b2: was the usual follow-up. I relied upon memory.

I remember when I first saw a move like :b2:. Its relation to :bc: seemed funny to me.

But let's compare this position with the one below.

Click Here To Show Diagram Code
[go]$$W
$$ ----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O O . O O 1 3 . 5 . . . . . . . . |
$$ | . O X X X X X 2 4 X . . . X . X X . . |
$$ | . X X . . . . . . . . . . . . . O . . |
$$ | . . O . . . . . . . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . O . . . . . . O . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . X . . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Really? (I went ahead and inserted :w5: ;)).

OC, Black won't really play :b4:. But then why would he play :b2:?

Edit:

Or how about these positions?

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


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