Life In 19x19 :: A not-so-good ponnuki

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A not-so-good ponnuki http://prod.lifein19x19.com/viewtopic.php?f=15&t=19024	Page 1 of 1

Author: xela [ Sun Jan 01, 2023 5:08 am ]

Post subject: A not-so-good ponnuki

Browsing the wonderful neural net go problems, I found this one surprisingly difficult, because both the preceding moves and the solution seem to go against basic instinct:

Click Here To Show Diagram Code: [go]$$B White to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . X O . . . . . . . . . . . . . . | $$ | . . X , . . . . . , O . . . O , O . . | $$ | . . X O . . . . . . . . . . . . . . . | $$ | . . X X O . . . . . . . . . . . . . . | $$ | . . . O O . . . . . . . . . . B . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . B . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 3 . . . | $$ | . . . . . . . . . . . . . . a 2 1 . . | $$ | . . . . . . . . . . . . . . . 5 c . . | $$ | . . . . . . . . . . . . . . . O b . . | $$ | . . . X . . . . . , . . . 4 . , . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Where should white play next? Hint: it's not at a!

I'm trying to understand the logic behind playing :w2:

and then abandoning it. My guesses so far are:

If white just plays at , then black has a good reply at b. But after the - exchange and then , if black plays b, then now c is a good reply for white.
After white's next move, if black captures at a, then the ponnuki so close to is a little overconcentrated.

Is this a reasonable way to think about this sequence?

If you're wondering, the problem position is Kobayashi (black) vs Kato, with 5.5 points komi; 1982-03-18a in GoGoD. But there's a bunch of other more recent games with the same corner position and followup.

Author:	Gomoto [ Sun Jan 01, 2023 7:01 am ]
Post subject:	Re: A not-so-good ponnuki
Click Here To Show Diagram Code [go]$$c $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . O . . . . . . . . . . . . . . \| $$ \| . . . X O . . . . . . . . . . . . . . \| $$ \| . . X , . . . . . , O . . . O , O . . \| $$ \| . . X O . . . . . . . . . . . . . . . \| $$ \| . . X X O . . . . . . . . . . . . . . \| $$ \| . . . O O . . . . . . . . . . B . . . \| $$ \| . . X . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . B . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . 4 3 . . . \| $$ \| . . . . . . . . . . . . . . . 2 1 . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . O . . . \| $$ \| . . . X . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . X . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] The logic about 2 is 4 ...

Author: Knotwilg [ Sun Jan 01, 2023 7:39 am ]

Post subject: Re: A not-so-good ponnuki

White's next move needs to be such that if Black takes the ponnuki, White can take clear profit (in the corner) and if Black protects the corner, drawing out the stone of the atari makes sense.

Click Here To Show Diagram Code: [go]$$W White to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . X O . . . . . . . . . . . . . . | $$ | . . X , . . . . . , O . . . O , O . . | $$ | . . X O . . . . . . . . . . . . . . . | $$ | . . X X O . . . . . . . . . . . . . . | $$ | . . . O O . . . . . . . . . . B . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . B . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . 2 O X . . | $$ | . . . . . . . . . . . . . . . X c . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . X . . . . . , . . . O . , 1 . . | $$ | . . . . . . . . . . . . . . . X 3 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

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

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

Not sure about this variation. White looks heavy.

Author: Gomoto [ Sun Jan 01, 2023 8:12 am ]

Post subject: Re: A not-so-good ponnuki

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

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

1 for 2 is not so good for black.

So perhaps after a black tenuki, the ponuki will never come into existence.

Click Here To Show Diagram Code: [go]$$c $$ . . . . . . . . . . | $$ , . . . . . X . . . | $$ . . . . . . . . . . | $$ . . . . . . X . . . | $$ . . . . . 2 O X . . | $$ . . . . . . X . . . | $$ . . . . . . O . . . | $$ , . . . O . O . . . | $$ . . . . . . X . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ ---------------------[/go]

Author:	Gomoto [ Sun Jan 01, 2023 8:35 am ]
Post subject:	Re: A not-so-good ponnuki
I do not think white 2 was played to be abandoned in any case. There are many reasonable variations with 2 played and many with 2 not played. White liked the variations after white 2 more. White 2 was played to influence the future development of the game.

Author:	Gomoto [ Sun Jan 01, 2023 8:44 am ]
Post subject:	Re: A not-so-good ponnuki
The link by the way: https://neuralnetgoproblems.com/ lightvector's site

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