Attach and block joseki

Bill Spight · #1

How bad is the attach and block joseki?

It has always made me feel uneasy, because it accepts a "bad" shape.

I am planning to show some pro examples from the Elf GoGoD commentaries, but feel free to join in with your own examples and comments.

Bill Spight · #2

Example 1

Ding Lie, 5 dan (W) vs. Zhang Yingting, 5 dan

GoGoD 2008-02-25q

Click Here To Show Diagram Code: [go]$$Bcm5 White takes the lead $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . 6 8 . . . . . . . . . . . . | $$ | . . . X 7 3 4 . . , . . . . . O . . . | $$ | . . . . 5 2 . . . . 1 . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Elf says that :b5:

loses 6% to par, but then :w6:

returns the favor, losing 6½% to par; minor errors. :b7:

, however, loses 9% to the kick at :b9:

. (See next diagram.) What about the block, :b9:

? Elf prefers the nobi at 10, but only by 1%. The block is surely playable.

Click Here To Show Diagram Code: [go]$$Bcm7 Kick and run $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 4 . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 3 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . 2 . . . , . . . . . O . . . | $$ | . . . . 1 O . . . . X . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In its mainline variation Elf chooses the kick, and after White stands, the one space jump. Then White invades the top right corner.

In this case the problem lies with the attachment, not the block, according to Elf.

Bill Spight · #3

Example 2.

Yamashita Keigo, 9 dan (W) vs. Yamada Takuji, 7 dan

GoGoD 2011-03-31i

Click Here To Show Diagram Code: [go]$$Bcm7 Tsuke OK $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . a . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 4 . . . | $$ | . . O . . . . . . . . . . . 6 3 2 . . | $$ | . . . . . . . . . . . . . . . 7 5 . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . X . . . 1 . . . . . . b . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Elf thinks that :b7:

loses 6% to the invasion of the top left corner at a, and that :b8:

loses 5% to the invasion of the bottom right corner at b; minor errors. This time the jump attachment, :b9:

, is Elf's top choice.

But the block, :b11:

loses 5% to the nobi at 12, another minor error. Elf's mainline variation is of some interest.

It is fairly long, based upon 77.3k rollouts.

Click Here To Show Diagram Code: [go]$$Bcm11 Elf's mainline variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . 6 . . . . | $$ | . . . . . . . . . . . . . 7 . . . . . | $$ | . . . . . . . . . . . . . 5 4 O . . . | $$ | . . O . . . . . . . . . . . 1 X O . . | $$ | . . . . . . . . . . . . . . . . . 2 . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . X . . . X . . . . . . 3 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The kosumi, :w12:

, avoids strengthening Black. Ditto :w16:

, but the cut is playable. Black continues strongly with :b17:

.

Click Here To Show Diagram Code: [go]$$Wcm18 Elf's mainline variation, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 7 . . . . | $$ | . . . . . . . . . . . . . 6 5 . . . . | $$ | . . . , . . . . . , . . . 4 3 , . . . | $$ | . . . . . . . . . . . . . 2 O . . . . | $$ | . . . . . . . . . . . . . X . . . . . | $$ | . . . . . . . . . . . . . X O O . . . | $$ | . . O . . . . . . 8 . . . 1 X X O . . | $$ | . . . . . . . . . . . . . . . . . O . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . X . . . X . . . . . . X 9 . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Now

cuts. Then White suffers being forced to crawl along the 5th line.

stakes out a large territorial framework. :w26:

is the last play Elf shows, with 2.3k rollouts. The next play, if any, gets fewer than 1500 rollouts. You can't be sure of plays that get few rollouts at the tail end of variations.

Elf's verdict in this case. The jump attachment is fine, but the block is a minor error.

Bill Spight · #4

Example 3.

Yi Chuyong, 6 dan (W) vs. Seo Pongsu, 9 dan

GoGoD 1991-03-28c

Click Here To Show Diagram Code: [go]$$Wcm8 Bread and Butter $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . . . . . . . . . . . | $$ | . . X 1 4 . . . . . . . . . . . . . . | $$ | . . 3 5 . . . . . . . . . . . . X . . | $$ | . . . O . . . . . , . . . . . , . . . | $$ | . . . . . . . . . O . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Here is a bread and butter example of the attach and block joseki, if there ever was one.

Elf says that the jump attachment, :w8:

, loses 5% to the kick at :w10:

, a minor error. The block, :w10:

, loses 3% to the nobi at :b11:

. For other bots a 3% difference might indicate a minor error, but Elf is fairly opinionated. IMO, the block is playable. Elf's variations look interesting.

Click Here To Show Diagram Code: [go]$$Wcm8 The Kick variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 4 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 5 . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X 2 . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . X . . | $$ | . . . O . 3 . . . , . . . . . , . . . | $$ | . . . . . . . . . O . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

White plays the kick, :w8:

(30k rollouts), followed by the one space jump. :b11:

approaches the top left corner and :w12:

is a mild pincer, looking both ways.

Click Here To Show Diagram Code: [go]$$Bcm13 The Kick variation, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 9 . 7 . . . . . . . . . . . . . | $$ | . . . O . 1 6 8 . , . . . . . X . . . | $$ | . . . . . 2 3 . . . . . . . . . . . . | $$ | . . X . . 4 . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 5 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . X . . | $$ | . . . O . O . . . , . . . . . , . . . | $$ | . . . . . . . . . O . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Black plays a double approach with :b13:

(6.3k rollouts). Then White attaches and extends. Black now makes a small base with :b17:

.

cuts and the fight continues. Surely :b21:

can't be the end, but now we are down to 1.6k rollouts, speculative territory.

Next, Elf's mainline variation for the nobi.

Click Here To Show Diagram Code: [go]$$Wcm10 The Nobi variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 4 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . 5 . 0 . . . . . . . . . . . . . | $$ | . . . . . 8 9 . . . . . . . . . . . . | $$ | . . . X 6 7 . . . . . . . . . . . . . | $$ | . . X O 1 . . . . . . . . . . . . . . | $$ | . 2 . . . . . . . . . . . . . . X . . | $$ | . . . O . . . . . , . . . . . , . . . | $$ | . . 3 . . . . . . O . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Elf prefers the nobi, :w10:

, with 57.7k rollouts. :b11:

and

are usual, then :b13:

approaches the top left corner. :w14:

attacks the Black stones in the bottom left. Both players continue strongly. :b15:

and

block, and :w16:

and

make a 2 step hane. :b19:

extends.

Click Here To Show Diagram Code: [go]$$Wcm20 The Nobi variation, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . 7 O . X 0 . . . . . . . . . . . . | $$ | . . 6 . . X O . . . . . . . . . . . . | $$ | . . . X X O 1 . . . . . . . . . . . . | $$ | . . X O O . . . . . . . . . . . . . . | $$ | . X . . . . . . . . . . . . . . X . . | $$ | 4 3 5 O . . . . . , . . . . . , . . . | $$ | . 2 O . . . . . . O . . . . . X . . . | $$ | . 8 9 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

makes a solid connection (9.8k rollouts). Black bolsters his position with :b21:

-

. White presses with :w26:

. Then Black makes a half eye in the corner with sente. The turn, :b29:

, is a strong, large scale play. Elf leaves us in media res again.

But we are down to 2k rollouts for :b29:

.

In this case, it appears that the jump attachment is a minor error, but the block is probably playable.

John Fairbairn · #5

Quote:

How bad is the attach and block joseki?

It has always made me feel uneasy, because it accepts a "bad" shape.

For the record, I said that Shibano wrote about tsukeosae having gone right out of fashion in the AI era, but he didn't quite say it had gone out of fashion because of AI. He said it enjoyed two waves of popularity, both before he became a pro. But humans had already concluded that it was usually best avoided.

The context he is talking in is not AI research as such, but rather "why have certain fuseki or joseki moves disappeared." AI is just one tool to help with the answers. But it appears that, with AI help, pros can be a little more certain of conclusions they had already reached.

There is an interesting example in this case. He starts off by saying that the reason tsukeosae disappeared was, in a nutshell, because of the empty triangle. However, he also gives another way of looking at it (which is more attuned to AI insights, perhaps). And that is that the tsukeosae side should feel uncomfortable about giving the opponent the atari that creates the empty triangle.

With this important difference: he does not call it an atari. he calls a tataki (a really strong atari, if you like - a strike rather than a hit). I think everyone can see how that might play into the typical AI centre-focused view of the go board, even if, like me, they don't understand the subtleties of how that tataki may reverberate.

But not every position is purely centre-focused, Shibano points out, and there are cases where the "greedy" joseki (jikara joseki) can work out. He summarises all that by saying that rather than regarding the tsukeosae as a go-to joseki, it should be regarded as a baai no te - a horses for courses move.

Bill Spight · #6

Example 4.

Chang Suyeong, 8 dan (W) vs. Seo Pongsu, 9 dan

GoGod 1991-11-14b

Click Here To Show Diagram Code: [go]$$Bcm9 Better nobi $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 2 . . . | $$ | . . O . . . . . . . . . . . 4 1 O . . | $$ | . . . . . . . . . . . . . . . 5 3 . . | $$ | . . . O . . . . . X . . . . . X . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This time Elf says that the jump attachment is correct, but the block loses 6½% to the nobi.

Here is Elf's mainline for the nobi.

Click Here To Show Diagram Code: [go]$$Bcm11 Nobi main line $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . 5 . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 9 . . . . . . . . . . . . . 4 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . 8 . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . 7 6 O . . . | $$ | . . O . . . . . . . . . . . 1 X O . . | $$ | . . . . . . . . . . . . . . . . . 2 . | $$ | . . . O . . . . . X . . . . . X . . . | $$ | . . . . . X . . . . . . . . . . 3 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

and

are usual. Then :w14:

approaches the top right corner. Black ignores the approach and makes an approach to the top left corner. :w16:

-

bolsters the White stones in the bottom right. Then :b19:

makes a double approach in the top left.

In this case the jump attachment is fine, but the block is a minor mistake.

Note that this is essentially the same verdict as for Example 2, where the bottom side stone is on the 3d line instead of the 4th line. And the recommended play after the nobi is quite different.

Bill Spight · #7

Example 5.

Seo Pongsu, 9 dan (W) vs. Yang Chaeho, 7 dan

GoGoD 1991-95-92b

It's Seo Pongsu night!

Click Here To Show Diagram Code: [go]$$Bcm9 Two enclosures $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O a . . . . X . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . O . . . . . . . . . . . . 5 3 . . | $$ | . . . . . . . . . . . . . . 4 1 O . . | $$ | . . . . . . . . . . . . . . . 2 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This time there are enclosures in the two adjacent corners, which affect the play. For :b9:

Elf prefers the 3d line attachment at a, but only by 2½%. The jump attachment is playable. However, Elf prefers the nobi to the block by 5%; so the block is a minor error.

Click Here To Show Diagram Code: [go]$$Bcm11 Nobi main line $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O 9 . . . . X . . . . . . 3 8 . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . O . . . . . . . . . . . . . . 2 . | $$ | . . . . . . . . . . . . . 6 1 X O . . | $$ | . . . . . . . . . . . . 7 5 4 O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

and

are usual. With the enclosures in place, White does not tenuki, but plays :w14:

and cuts after the Black hane. :b17:

extends into the center. Then :w18:

plays the S-17 attachment. At this point Black switches to the 3d line attachment in the top left corner, preparing for a large scale fight.

Click Here To Show Diagram Code: [go]$$Wcm20 Nobi main line, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O X . . . 8 X . . 6 . . . X O . | $$ | . . . , 1 2 . . . 7 . 9 . . 4 X 5 . . | $$ | . . O . . . . . . . . . . 3 . . . O . | $$ | . . . . . . . . . . . 0 . O X X O . . | $$ | . . . . . . . . . . . . X X O O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

After the hane and counter hane in the top left corner, :w22:

returns the fight to the top right. Both sides bolster their positions, and then :w26:

attaches on the 4th line to the top center stone. :b27:

extends to the left, and the fighting continues. After :b29:

it looks like Elf has left us in the middle of things again. However, :b29:

gets 3.5k rollouts. If there is another play in this variation, there is a drop of at least 2k rollouts for it. To me that suggests that there are a number of reasonable options, and White might well tenuki.

Once again the jump attachment is playable while the block is a minor error. That is not the only pattern, OC. But so far, either the jump attachment or the block has been a small mistake.

Bill Spight · #8

Example 6.

Yashiro Kumiko, 6 dan (W) vs. Takemiya Masaaki, 9 dan

GoGoD 2016-02-94a

Click Here To Show Diagram Code: [go]$$Wcm14 No mistakes $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . a . . . . . . . O . . . . . | $$ | . . . O . . . . . , O . . . . X . . . | $$ | . . 3 5 . . . . . . . . . . . . . . . | $$ | . . X 1 4 . . . . . . . . . . X . . . | $$ | . . . 2 6 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . X . O . . . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Elf does not rate either the jump attachment or the block as a mistake.

It does prefer the keima at a to the jump attachment, and the nobi to the block, but only by 3% each. Elf does prefer another play to :b19:

but only by 2½%. It's a bit of a surprise that Takemiya did not play it, because it's a Takemiya style play.

Click Here To Show Diagram Code: [go]$$Bcm19 Takemiya style variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . O . . . . . | $$ | . . . O . . . . . , O . . . . X . . . | $$ | . . O O . . . . . . . . . . 4 5 . . . | $$ | . 7 X O X . . . . . . . . . . X . . . | $$ | . . 2 X . . 1 . . . . . . . . . . . . | $$ | . 8 . 3 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . 6 . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . 9 . X . O . . . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

How did Takemiya miss the central keima, :b19:

?

(88.1k rollouts.) After :w20:

;b21: extends on the 4th line to make a center facing group. Then White plays the jump in the bottom left. Next, Black extends with :b25:

as a sacrifice. :w26:

accepts efficiently. Then :b27:

plays to make sabaki in the bottom left corner.

Click Here To Show Diagram Code: [go]$$Wcm28 Takemiya style variation, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . O . . . . . | $$ | . . . O . . . . . , O . . . . X . . . | $$ | . . O O . . . . . . . . . . O X . . . | $$ | . X X O X . . . . . . . . . . X . . . | $$ | . . O X . . X . . . . . . . . . . . . | $$ | . O . X . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . 8 . . . O . . . . . . . . . . . | $$ | . . 9 O 6 . . . . , . . . . . X . . . | $$ | . . 1 X . X . O . 0 . . X . . . . . . | $$ | . 3 2 7 4 . . . . . . . . . . . . . . | $$ | . . 5 . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

White replies strongly with a 2 step hane and then atari. Black continues lightly, approaching with :b37:

and leaving a ko behind.

Finally we have a tsukeosae joseki that seems to be playable.

Bill Spight · #9

Example 7.

Yi Tonghun, 5 dan (W) vs. Ida Atsushi, 8 dan

GoGoD 2015-08-25b

Click Here To Show Diagram Code: [go]$$Bcm11 White's mistake $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . O 3 . . . . | $$ | . . . O . . . . X 6 . . 2 1 5 X . . . | $$ | . . . . . . . . . . . . . 4 . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In this case Elf prefers the kick at :b13:

to

, but only by 3%. It also prefers the nobi at 14 to :b13:

, but only by 1½%. The attach and block joseki appears to be playable.

:w16:

is creative, but loses 6½% to par, a minor error.

Here is Elf's mainline variation for :w16:

.

Click Here To Show Diagram Code: [go]$$Wcm16 Elf's main line for $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . 9 6 8 5 . . . . . | $$ | . . . . . X . . . 7 . . 2 O X . . . . | $$ | . . . O . . . . X . . 3 O X X X . . . | $$ | . . . . . . . . . . . . . O . . . . . | $$ | . . O . . . . . . . . . 1 . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . 4 . . , . . . . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Any resemblance of White's strategy here to Black's strategy in the previous example is not coinicidental.

and

form a central group. :b19:

is a now normal shoulder blow. :w20:

is a sacrifice, and :b21:

is efficient. :w22:

threatens to atari at 23. Finally, :w24:

makes shape.

This is an even better example of the attach and block joseki being playable.

Bill Spight · **#10**

Example 8.

Anzai Nobuaki, 6 dan (W) vs. Ida Atsushi, 4 dan

GoGoD 2012-09-17h

Click Here To Show Diagram Code: [go]$$Bcm11 Playable $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . 9 7 O 3 . . . . | $$ | . . . O . . . . X , . 8 2 1 5 X . . . | $$ | . . . . . . . . . . . . . 4 . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . 6 . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . B . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Each play in this actual game sequence is playable. :b11:

loses 3% to par, :b13:

loses 2½% to par, and :w18:

loses 1% to par, according to Elf. This is hardly surprising, as the only difference between this example and the previous one is that the Black stone on the right side is on the 3d line instead of the 4th line.

Bill Spight · **#11**

Example 9.

Takao Shinji, 9 dan (W) vs. Iyama Yuta, 9 dan

GoGoD 2015-03-29c

Click Here To Show Diagram Code: [go]$$Bcm15 Playable $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . O . . X . . X . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . 5 3 . . | $$ | . . O . . . . . . . . . . . 4 1 O . . | $$ | . . . . . . . . . . . . . . . 2 7 . . | $$ | . . . . . . . . . . . . . . . 8 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . 6 9 . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . O . . . . . , . . O . . , . . . | $$ | . . . . . . . . . O . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Again, this sequence from the actual game should be playable. No loss to par greater than 2½%.

This was something of a surprise. I went looking for the last example, to see if there was any difference between the high Chinese and low Chinese. This occurs in the high Chinese, but I didn't go looking for it.

Not that these choices are random. I chose a group of games where the attach and block occurs by move 30. There are too many factors that might affect the decision after that, I think. But from that group of games I started with games where the joseki occurred early in the game. Now I'm on games where the jump attachment occurs in the teens. That may matter.

Bill Spight · **#12**

Example 10.

Zhou Junxun, 7 dan (W) vs. Cho Hanseung, 2 dan

GoGoD 1998-06-16g

Click Here To Show Diagram Code: [go]$$Bcm13 Playable $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . O . . X . . X . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . 5 3 . . | $$ | . . O . . . . . . . . . . . 4 1 O 6 . | $$ | . . . . . . . . . . . . . . . 2 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . O . . . . . , . . . . . , . . . | $$ | . . . . . . O . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Another playable game sequence.

The jump attachment is Elf's top choice, the block loses 2½% to the nobi. BTW, the sagari, :w18:

is Elf's top choice against the attach and block, and it often is.

Bill Spight · **#13**

Example 11.

Tan Xiao, 7 dan (W) vs. Ida Atsushi, 3 dan

GoGoD 2012-10-18b

Click Here To Show Diagram Code: [go]$$Bcm11 Playable $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . O 3 . . . . | $$ | . . . O . . . . X , . . 2 1 5 X . . . | $$ | . . . . . . . . . . . . 6 4 . . . . . | $$ | . . O . . . . . . . . . . . . 7 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . O . . . . . , . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Not much of a surprise. Another Chinese Opening position with Black strength on the top side. The bottom side is different, however.

Bill Spight · **#14**

Example 12.

Luo Xihe, 5 dan (W) vs. Yu Bin, 9 dan

GoGoD 1994-08-16e

Click Here To Show Diagram Code: [go]$$Bcm13 Not just playable $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . O 3 . . . . | $$ | . . . O . . . . X , . . 2 1 5 X . . . | $$ | . . . . . . . . . . . . . 4 . . . . . | $$ | . . O . . . . . . . . 6 . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . O . . . . . O . a . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This sequence is not just playable, the block, :b15:

, is Elf's top choice. (As are :w16:

,

and

.) This is not a Chinese Opening position, but Black has developed on both sides. :b19:

was the extension to a, but Elf has a different idea.

Click Here To Show Diagram Code: [go]$$Bcm19 Main variation for $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . 5 3 O X . . . . | $$ | . . . O . . . . X , . . O X X X . . . | $$ | . . . . . . . . . . . 2 1 O . . . . . | $$ | . . O . . . . . . . . O 4 . . 6 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 7 . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . O . . . . . O . . . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

is a sacrifice to connect underneath. White builds outside strength, and then Black plays the shoulder blow in the bottom left corner.

Bill Spight · **#15**

Example 13.

Yamada Kimio, 9 dan (W) vs. Nakano Hironari, 9 dan

GoGoD 2014-01-09l

Click Here To Show Diagram Code: [go]$$Wcm16 Minor error $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . O . . . O X X . . . | $$ | . . . O . . . . . , . . . O O , X . . | $$ | . . 3 5 . . . . . . . . . . . X . . . | $$ | . . X 1 4 . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . X . . . . . X . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The jump attachment is Elf's top choice. The block loses 5% to the nobi, a minor error.

Click Here To Show Diagram Code: [go]$$Wcm18 Nobi main line variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 3 . . . . . . O . . . O X X . . . | $$ | . . . O . . . . . , . . . O O , X . . | $$ | . 2 . . . . . . . . . . . . . X . . . | $$ | . . X O 1 6 . 9 . . . . . . . . . . . | $$ | . . . X 4 5 . . . . . . . . . . . . . | $$ | . . . . . 7 . . . . . . . . . . . . . | $$ | . . 8 . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . X . . . . . X . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

cuts, to which :w24:

is a strong extension. :b25:

makes a base. Then :w26:

pincers the cutting stone.

Click Here To Show Diagram Code: [go]$$Bcm27 Nobi main line variation, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . 2 O . 6 . O X X . . . | $$ | . . . O . . . . . 1 . 5 . O O , X . . | $$ | . X . . . . . . . . . . . . . X . . . | $$ | . . X O O X . O . . . . . 3 . . . . . | $$ | . . . X X O . . . . . . . . . . . . . | $$ | . . . . . O . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . 7 . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . 4 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . 8 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . X . . . . . X . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

plays the 4th line attachment, and :w28:

pulls back. Then :b29:

plays the keima. :w30:

is a wedge on the right side. Black takes kikashi in the top right and then approaches :w30:

from the top, making a territorial framework. :w34:

makes a base, threatening Black's thin corner position.

At last another example where the block loses enough percentage points to the nobi to be considered a minor error. The nobi enables White to build a moyo on the top side.

Uberdude · **#16**

John Fairbairn wrote:

Quote:

How bad is the attach and block joseki?

It has always made me feel uneasy, because it accepts a "bad" shape.

There is an interesting example in this case. He starts off by saying that the reason tsukeosae disappeared was, in a nutshell, because of the empty triangle. However, he also gives another way of looking at it (which is more attuned to AI insights, perhaps). And that is that the tsukeosae side should feel uncomfortable about giving the opponent the atari that creates the empty triangle.

Uberdude wrote:

one of the lessons I've picked up from bots is how much they dislike letting the opponent make gains in local efficiency of shapes in sente*, even if there is a directional benefit to it.

Bill Spight · **#17**

Example 14.

Guo Yuzheng, 3 dan (W) vs. Chang Hao, 9 dan

GoGoD 2013-05-09i

Click Here To Show Diagram Code: [go]$$Bcm17 Jump attachment playable, block minor mistake $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . 6 . . . . . | $$ | . . O . . O . . . . . . . O 3 . . . . | $$ | . X . O . . . . . , . . 2 1 5 X . . . | $$ | . . . . . . . . . . . . . 4 . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . O . . . . . O . . O . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Again, not too surprising, as Black only has something on the right side, while White has something on the top. As usual, Elf recommends the kick and the nobi.

Click Here To Show Diagram Code: [go]$$Bcm17 Mainline variation for the kick $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 9 . . . . | $$ | . . O . . O . . . . . . . O 1 . 8 . . | $$ | . X . O . . . . . , 4 . . 2 . X . . . | $$ | . . . . . . . . . . . . . . . . . 6 . | $$ | . . X . 5 . . . . . . . . . . 3 . . . | $$ | . . . . . . . . . . . . . . . . 7 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . O . . . . . O . . O . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In the old days the kick would have been questionable, as it strengthens White without any obvious attack. :w20:

makes only a 2 space high extension. :b21:

plays on the frontier of two frameworks. Then :w22:

plays a submarine invasion, aiming both ways. :b23:

blocks off the side, and :w24:

occupies the 3-3. The descent, :b25:

, aims both ways.

Click Here To Show Diagram Code: [go]$$Wcm26 Mainline variation for the kick, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . 7 . . . . . . X . . . . | $$ | . . O . . O . 9 8 . . . . O X . O . . | $$ | . X . O . . 6 . . , O . . O . X 1 . . | $$ | . . . . . . . . . 0 . . . . . 2 . O . | $$ | . . X . X . . . . . . . . . . X . 5 . | $$ | . . . . . . . . . . . . . . . . X 3 . | $$ | . . . . . . . . . . . . . . . . . 4 . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . O . . . . . O . . O . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

-

secures the corner group with gote. Then :b31:

leans on White group in the top left with a shoulder blow. :w32:

slides to the second line, but :b33:

makes another shoulder blow on the 3d line, keeping the White groups separated. After White pushes up with :w34:

,

attacks the White group in the top right side with another shoulder blow. Note that :b31:

,

, and

form a dogleg keima shape.

Click Here To Show Diagram Code: [go]$$Bcm19 Mainline variation for the nobi $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . 6 . 2 . 4 . . | $$ | . . O . . O . . . . . . . O 5 . 3 . . | $$ | . X . O . . . . . , . 8 O X . X . . . | $$ | . . . . . . . . . . . . 7 1 . . . . . | $$ | . . X . . . . . . . 9 . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . 0 . , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . O . . . . . O . . O . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

After the nobi, :w20:

and

are usual. Then :w22:

plays to stabilize the White group with strengethening Black too much. Still, Black gets the turn, :b25:

, with sente and then plays the double keima with :b27:

. Then

plays a shallow reduction on the right side.

Follow-up to the attach and block

Click Here To Show Diagram Code: [go]$$Bcm23 Mainline variation for $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . 6 . O 8 . . . . | $$ | . . O . . O . . . . . . . O X . . . . | $$ | . X . O . . . . . , 5 2 O X X X . . . | $$ | . . . . . . . . . 0 4 3 1 W . . . . . | $$ | . . X . . . . . . . . . . 9 . . . . . | $$ | . . . . . . . . . . . 7 . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . O . . . . . O . . O . . , . . . | $$ | . . . . . O . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]