I had a rather interesting position/question arising from one of my recent OGS title matches (
http://www.online-go.com/games/board.php?boardID=368626).
I was black and had 3 corners, and was going for a 4th.
- Click Here To Show Diagram Code
[go]$$Bc Uberdude (black) vs Elin
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . W O O X . . . . . . . . . X . . . . |
$$ | . . X X O . . . . , . . . . . , X . . |
$$ | . . X . O . . . . . . . . . . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
The usual joseki move for black here is d18 to capture the corner, allowing white to squeeze on the outside. I would have been content with the variation below in which white nobis at c13. Black gets a decent sized corner, white some nice thickness (but isn't the left side a smidgen overconcentrated?) and sente to get the big point of
a.
- Click Here To Show Diagram Code
[go]$$Bc White is kind
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 7 . 1 X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . X . . . . |
$$ | . . X X O . . . . , . . . . . , X . . |
$$ | . . X . O . . . . . . . . . . . . . . |
$$ | . 3 2 . . . . . . . . . . . . . a . . |
$$ | . 5 4 . . . . . . . . . . . . . . . . |
$$ | . 6 . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
However, I feared white playing the hane at b13 as below. If I submit I get a slightly inferior result to above (a few points difference and no d12 peep, though both still have the e13 vital point to aim at). There are also some other possibilities for white such as not immediately connecting at c13 but exchanging c18 for b19 to make it annoying for me to capture the corner and then he can push me down to the 2nd line at e17 in sente for more thickness.
- Click Here To Show Diagram Code
[go]$$Bc White is severe
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 7 . 1 X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . X . . . . |
$$ | . . X X O . . . . , . . . . . , X . . |
$$ | . 5 X . O . . . . . . . . . . . . . . |
$$ | . 3 2 . . . . . . . . . . . . . . . . |
$$ | . 4 6 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
There is a ladder white needs black to not have to be able to double-hane like this, which is the case (if d connects at e then g18 leads to a huge ko which black takes first):
- Click Here To Show Diagram Code
[go]$$Bc The ladder needed to double hane
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X X . . . . . . . . . . . . . . |
$$ | . O O O X . b . . . . . . . X . . . . |
$$ | . . X X O 8 0 a . , . . . . . , X . . |
$$ | . . X 3 O 7 9 c . . . . . . . . . . . |
$$ | . X O 1 5 6 . . . . . . . . . . . . . |
$$ | . O 2 d 4 e . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
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$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
So because white had the ladder and could thus double hane, I decided to play d14 kosumi first. The joseki answer for white is to block, indeed this is the move played in 33 of the 35 pro games in my GoGoD. I would be happy with the result below (more territory than before). Somewhat similar to the double hane, white can also play 6 one space to the left to pressure black more. There is some coverage of this in Tournament Go 92 as it was played in the Kobayashi-Shuko Oza title match. GoGoD shows this more severe move is the norm from the late 80s onwards. There are some rather complex variations in the corner, but as black gets a cutting atari at e13 I thought that could help with reducing the white moyo/territory on the left.
- Click Here To Show Diagram Code
[go]$$Bc Kosumi joseki
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 3 X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . X . . . . |
$$ | . 7 X X O . . . . , . . . . . , X . . |
$$ | . . X . O . . . . . . . . . . . . . . |
$$ | . . . 1 2 . . . . . . . . . . . . . . |
$$ | . . 5 4 . . . . . . . . . . . . . . . |
$$ | . . . 6 . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
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$$ ---------------------------------------[/go]
Anyway, I had a sneaking feeling when I played the kosumi that white might not block on the outside as in the joseki (as it follows my plan of improving on the d18 joseki and it seems a tough game for white when black has all four corners), but instead block in the corner. He has to spend gote to live there with an L+1 group, but black is then cut into 2 weakish groups: the top group is not perhaps so weak, though it is still susceptible to a checking extension, but the left group does feels pretty weak with c11 and that thickness down below menacing it. I felt rather uncomfortable at this point.
- Click Here To Show Diagram Code
[go]$$Bc Oh noes! Cut into 2 groups.
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$$ | . 6 . . . . . . . . . . . . . . . . . |
$$ | . . . 2 X . . . . . . . . . . . . . . |
$$ | . O O O X . 3 . . . . . . . X . . . . |
$$ | . 4 X X O . . . . , . . . . . , X . . |
$$ | . 5 X . O . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
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$$ | . . O . . . . . . . . . . . . . O . . |
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$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
So now come my questions. What do people think of this position? Is it good for white, is black in for a hard fight? I was rather surprised that there were no games in GoGoD in which white blocked at d18. Perhaps this is an example of the catch-22 in using pro games to study positions like this: if this fight was good for white then black wouldn't have played the d14 kosumi but the safe d18, so we never get examples of this d18 block and fight. What should black's next move be? I wasn't sure if I should jump at g15, which white answers at e14 (or f14?), to induce running out at d12, or whether to d12 directly. In the game I went for the later, and the fighting went as below. I really wished I could play f11 at g11 (and I assumed I could when I played d12), but it was only after white c10 that I realised g11 was too thin and vulnerable to the e13 f11 cutting combo.
- Click Here To Show Diagram Code
[go]$$Bc Fight continuation
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$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . O O O X . X . . . . . . . X . . . . |
$$ | . O X X O . . . 3 , . . . . . , X . . |
$$ | . X X . O . 2 . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . 4 . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . O 5 . 7 . . . . . . . . . . O . . |
$$ | . . 6 , . . . . . , . . . . . , . . . |
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$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X O O . . . . . . . . . . . O . . |
$$ | . . O O X O . . . . . . . . . O X . . |
$$ | . . O X X . . . . , . . . . . , X . . |
$$ | . O X O X . . . . . . . . X . X . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Questions? Comments?*
*Bonus points if you can identify which episode of Buffy this is a quote from