Attach and block joseki

Uberdude · Post by **Uberdude** » Wed May 13, 2020 10:05 pm

John Fairbairn wrote:
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 · Post by **Bill Spight** » Thu May 14, 2020 12:05 pm

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.

makes only a 2 space high extension.

plays on the frontier of two frameworks. Then

plays a submarine invasion, aiming both ways.

blocks off the side, and

occupies the 3-3. The descent,

, 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

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

slides to the second line, but

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

,

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

,

, 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,

and

are usual. Then

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

, with sente and then plays the double keima with

. Then

plays a shallow reduction on the right side.

Follow-up to the attach and block

Click Here To Show Diagram Code: [go]$$Bcm23 Mainline variation for :b23: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . 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]

cuts in sente, as

extends. In the skirmish

pushes,

blocks, and

cuts.

makes eyeshape. Then

jumps into the center.

turns on the 2d line, threatening the corner.

grabs the

stone, securing the Black stones. Then

fortifies White's top side.

Life In 19x19

Attach and block joseki

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Re: Attach and block joseki