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People may remember this game from Strategtic Concepts of Go by Nagahara.

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$$|. . . 2 . . . . . . . . . . . . . . .|
$$|. . . O X . . . . . . . . . . . . . .|
$$|. . O X . . . . . 3 . . . . . X . . .|
$$|. . O X . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . 4 . . . . .|
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$$ ---------------------------------------

I want to know why white has to play toward the edge with 2. When black has gone and grabbed both star points, that just doesn't seem like a fair trade somehow. So why did white make that choice?

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2 Answers 2

up vote 16 down vote accepted

First of all, I want to insist that my answer is not 'dogmatic'. It is rather the way I like to think and rather a guideline instead of a deterministic answer.

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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O X . . . . . . . . . . . . . .|
$$|. . O X . . . . . , . . . . . X . . .|
$$|. . O X . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
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$$|. . . , . . . . . , . . . . . 1 . . .|
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$$|. . . O . . . . . , . . . . . X . . .|
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$$ ---------------------------------------

Let us analyze the different possible moves for White in this situation. Right now, Black is building up a large influence framework on the right. This strategies is supported by the fact that his stones on the upper left face toward the center.

However, to do so, he interrupted the large avalanche joseki, thus giving White the opportunity to take advantage of it locally.

Consequently, it seems attractive for White to play in this corner. Suppose White wants to pincer like in the following diagram.

$$W
$$---------------------------------------
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O X . . . . . . . . . . . . . .|
$$|. . O X . . . . . 1 . . . . . X . . .|
$$|. . O X . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . , . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
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$$ ---------------------------------------

In this case, Black can settle easily, for instance like in the next figure.

$$ ---------------------------------------
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . 1 . . . . . . . . . . . . . . .|
$$|. . 2 O X . . . . . . . . . . . . . .|
$$|. . O X . 3 . . . O . . . . . X . . .|
$$|. . O X . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . , . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . . . . . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------

Of course, there are many many other possibilities for Black, but the important point is that White has no attack! Black has too much aji to make sabaki for White to hope to attack him. Hence, White's attack stone lost his meaning and is now floating inside Black's sphere of influence without suitable backup!

Hence, if White wants to play in this corner, it seems natural to kill all the possible Black's aji. The perfect move for this is White 1 in the next diagram.

$$W
$$ ---------------------------------------
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . 1 . . . . . . . . . . . . . . .|
$$|. . . O X . . . . . . . . . . . . . .|
$$|. . O X . . . . . , . . . . . X . . .|
$$|. . O X . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . , . . . . . , . . . . . X . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------

This move has the several main positive points:

  • It takes a lot of points (the corner is worth about 15 points, probably more to come).
  • It completely kills Black's aji.
  • It threatens severly Black. Indeed, now a pincer would be very severe.

Consequently, Black answers at 2:

$$W
$$ ---------------------------------------
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . 1 . . . . . . . . . . . . . . .|
$$|. . . O X . . . . . . . . . . . . . .|
$$|. . O X . . . . . 2 . . . . . X . . .|
$$|. . O X . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . , . . . . . , . . . . . X . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------

But still, the upper left part cannot be considered as Black's territory since Black is much too weak on the upper left corner. Hence the situation as to be considered as a yonrensei where White has now the initiative.

The Black stones in the upper left are in fact to be considered as light, forcing moves. Another way of seeing it, is to have a look at the following tewari. Suppose the following fuseki is taking place.

$$W
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . . . . . . . . . . .|
$$|. . . , . . . . . X . . . . . X . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
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$$|. . . , . . . . . , . . . . . X . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . O . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------

Wouldn't it be completely ajikeshi for Black to play like in the following diagram?

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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . 6 . . . . . . . . . . . . . . .|
$$|. . . O 5 . . . . . . . . . . . . . .|
$$|. . 4 3 . . . . . X . . . . . X . . .|
$$|. . 2 1 . . . . . . . . . . . . . . .|
$$|. . O . . . . . . . . . . . . . . . .|
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$$|. . . , . . . . . , . . . . . X . . .|
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$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . O . . . . . , . . . . . X . . .|
$$|. . . . . . . . . . . . . O . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$|. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------

Hope this helps ;-)

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1  
that's an excellent answer. i wish i could give it more than one upvote. –  magnetar Nov 27 '11 at 17:33
    
Thank you very much ;-) –  Thomas Connor Nov 28 '11 at 7:36
    
Not sure, but an additional thought might be to have black initiate large avalanche in case white tenukis. So black would get a locally even position too, which is too nice since he already took a spot elsewhere. By the sagari of W2, this is impossible, and of course it makes for good mid- and endgame too. –  mafu Nov 30 '11 at 12:41
    
That's for sure. However, it becomes extremely complicated to determine when could Black start the avalanche in order to achieve an equal (or better position). Taking account of the rest of the board makes it far to complicated. Since it is so difficult to evaluate, I prefer to give the above arguments that justify White's second line move. –  Thomas Connor Nov 30 '11 at 16:01
    
+1: excellent answer. This kind of question / answer is just what I expect from go.stackexchange.com ^^ –  neuro Dec 2 '11 at 15:27

White is playing good moves that largely cancel Black's starpoint stones. Because it is closer to the edge than Black's stones, White's move 2 undercuts the zone that Black is trying to stake out with move 3.

Likewise, White's move 4 is an appropriate response to Black's star point move at 1. This prevents Black from expanding along the bottom from his san-ren-sei on the right. If he pincers White's stone (probably his best move), White makes a one point jump into the center that largely nullifies the influence of Black's two star point stones.

White could have taken the star point at the bottom, but White 4 is more aggressive. In general, star point stones are big moves at this stage of the game. But White had equally big moves with his descent to the edge (at 2), and his kakari at 4. As such, he doesn't "mind" having Black take the star points.

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