Pattern problem

clemi · Post by **clemi** » Mon May 04, 2015 7:19 am

Click Here To Show Diagram Code: [go]$$B Black to play first. Choose between a and b $$ -------------------- $$ |. . . . . . . . . . $$ |. a O O b . . . . . $$ |. X X O X . . . . . $$ |. O O X X O . . . , $$ |. . . . . . . . . . $$ |. . X . . . . . . . $$ |. . . . . . . . . .[/go]

I'm currently studying Lee Chang Ho Course, middle level, book 1 and stumbled accross the above problem in lesson 7.

The correct answer is A. Anyone any idea why A is eventually better than B ?

DrStraw · Post by **DrStraw** » Mon May 04, 2015 7:22 am

Either way white must capture the corner stones and black gets to play B. But if A is on the board then white cannot later hane and connect at the top so that becomes black's privilege later.

clemi · Post by **clemi** » Mon May 04, 2015 7:28 am

Thanks DrStraw for seeing the better yose continuation, that's the kind of thing I need to improve.

macelee · Post by **macelee** » Mon May 04, 2015 9:34 am

Also there is one extra (rather big) ko threat left there if black plays the correct move.

illluck · Post by **illluck** » Mon May 04, 2015 10:30 am

Probably a question indicative of bad hibits, but are there cases where black might want to play b because if black plays a white will play b first?

Click Here To Show Diagram Code: [go]$$B Black to play first. Choose between a and b $$ -------------------- $$ |. . . . . . . . . . $$ |. 1 O O 2 . . . . . $$ |. X X O X . . . . . $$ |. O O X X O . . . , $$ |. . . . . . . . . . $$ |. . X . . . . . . . $$ |. . . . . . . . . .[/go]

DrStraw · Post by **DrStraw** » Mon May 04, 2015 10:42 am

illluck wrote:Probably a question indicative of bad hibits, but are there cases where black might want to play b because if black plays a white will play b first?

Click Here To Show Diagram Code: [go]$$B Black to play first. Choose between a and b $$ -------------------- $$ |. . . . . . . . . . $$ |. 1 O O 2 . . . . . $$ |. X X O X 4 . . . . $$ |. O O X X O . . . , $$ |. . 3 . . . . . . . $$ |. . X . a . . . . . $$ |. . . . . . . . . .[/go]

If W has positions on both sides this is conceivable, but I think the point of the exercise was the best way to force W to capture the corner. Also, given the B has a nice shape move at A it is hard for W to play this way.

Uberdude · Post by **Uberdude** » Mon May 04, 2015 12:38 pm

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

Black might also answer because you helped him damage your outside stone, and 5 in sente is huge. In the usual joseki by blocking at the top in sente the left block is no longer sente so there is a cut on the left. I once lost a game and a tournament and about £50 because I misjudged the severity of this cut.

Click Here To Show Diagram Code: [go]$$B $$ -------------------- $$ |. 2 . . . . . . . . $$ |4 1 O O 3 . . . . . $$ |. X X O X . . . . . $$ |. O O X X O . . . , $$ |. . . 0 . . . . . . $$ |. . X . . . . . . . $$ |. . . . . . . . . .[/go]

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