For those interested, here is a classical problem. For those who have not seen it before, it may be harder than its appearance.
$$B Black to play $$ ----------------------- $$ . . . . . . . . . O . . $$ . . . . . O . . . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B Black to play $$ ----------------------- $$ . . . . . . . . . O . . $$ . . . . . O . . . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
Re: Classical problem
Posted: Sun Feb 20, 2011 1:55 am
by tj86430
Naturally my first instinct is:
$$B Black to play $$ ----------------------- $$ . . . . . . . . . O . . $$ . . . . . O . B . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B Black to play $$ ----------------------- $$ . . . . . . . . . O . . $$ . . . . . O . B . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
and I can't see how white would survive, but since this is supposed to be hard I guess it's wrong.
Re: Classical problem
Posted: Sun Feb 20, 2011 3:15 am
by daniel_the_smith
@tj:
$$W Black to play $$ ----------------------- $$ . . . . . . . 1 . O . . $$ . . . . . O 3 B 2 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$W Black to play $$ ----------------------- $$ . . . . . . . 1 . O . . $$ . . . . . O 3 B 2 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
$$W Black to play $$ ----------------------- $$ . . . . . . . 1 . O . . $$ . . . . . O 2 B 3 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$W Black to play $$ ----------------------- $$ . . . . . . . 1 . O . . $$ . . . . . O 2 B 3 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
I was about to post a solution but mine was wrong too... >.<
Re: Classical problem
Posted: Sun Feb 20, 2011 3:25 am
by Jordus
@Daniel Smith
i think defeats your ...
$$W Black to play $$ ----------------------- $$ . . . . . 5 2 1 3 O . . $$ . . . . 6 O 4 B . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$W Black to play $$ ----------------------- $$ . . . . . 5 2 1 3 O . . $$ . . . . 6 O 4 B . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
only 1 eye if white captures blacks 3 stones because black will play @ 4.
$$W @ 1 @1 $$ ----------------------- $$ . . . . . 7 2 1 4 O . . $$ . . . . . O 3 B 5 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$W @ 1 @1 $$ ----------------------- $$ . . . . . 7 2 1 4 O . . $$ . . . . . O 3 B 5 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
Re: Classical problem
Posted: Sun Feb 20, 2011 3:26 am
by Sverre
unkx80 wrote:For those interested, here is a classical problem. For those who have not seen it before, it may be harder than its appearance.
$$B I think ko is best. $$ ----------------------- $$ . . . . . . 3 2 . O . . $$ . . . . . O . 1 4 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B I think ko is best. $$ ----------------------- $$ . . . . . . 3 2 . O . . $$ . . . . . O . 1 4 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
$$B If W gets the comb formation he lives, so we need a placement. $$ ----------------------- $$ . . . . . 2 . . . O . . $$ . . . . 1 O . . . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B If W gets the comb formation he lives, so we need a placement. $$ ----------------------- $$ . . . . . 2 . . . O . . $$ . . . . 1 O . . . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
$$B This looks tempting, but the liberty at a is inconvenient. $$ ----------------------- $$ . . . . . . 2 1 . O . . $$ . . . . 4 O . 3 . O X . $$ . X . X X X O O O X X . $$ . . . . . . X a X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B This looks tempting, but the liberty at a is inconvenient. $$ ----------------------- $$ . . . . . . 2 1 . O . . $$ . . . . 4 O . 3 . O X . $$ . X . X X X O O O X X . $$ . . . . . . X a X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
$$B And the other placement seems to force a ko. $$ ----------------------- $$ . . . . . . 3 2 . O . . $$ . . . . . O . 1 4 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B And the other placement seems to force a ko. $$ ----------------------- $$ . . . . . . 3 2 . O . . $$ . . . . . O . 1 4 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
$$B Playing something like still ends up in ko. $$ ----------------------- $$ . . . . . . 1 2 . O . . $$ . . . . . O . 3 4 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B Playing something like still ends up in ko. $$ ----------------------- $$ . . . . . . 1 2 . O . . $$ . . . . . O . 3 4 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
EDIT:
Forgot this variation, if I missed something it's probably somehow related to this .
$$B The Black attachment is tricky, is this right? $$ ----------------------- $$ . . . . 6 1 5 3 . O 7 . $$ . . . . 2 O 8 4 . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B The Black attachment is tricky, is this right? $$ ----------------------- $$ . . . . 6 1 5 3 . O 7 . $$ . . . . 2 O 8 4 . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
Re: Classical problem
Posted: Sun Feb 20, 2011 3:35 am
by tj86430
Jordus wrote:@Daniel Smith
i think defeats your ...
$$W Black to play $$ ----------------------- $$ . . . . . 5 2 1 3 O . . $$ . . . . 6 O 4 B . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$W Black to play $$ ----------------------- $$ . . . . . 5 2 1 3 O . . $$ . . . . 6 O 4 B . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
only 1 eye if white captures blacks 3 stones because black will play @ 4.
$$W @ 1 @1 $$ ----------------------- $$ . . . . . 7 2 1 4 O . . $$ . . . . . O 3 B 5 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$W @ 1 @1 $$ ----------------------- $$ . . . . . 7 2 1 4 O . . $$ . . . . . O 3 B 5 O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
This is what I had in mind
Re: Classical problem
Posted: Sun Feb 20, 2011 4:12 am
by daniel_the_smith
Re: Classical problem
Posted: Sun Feb 20, 2011 4:59 am
by explo
@ Jordus, Daniel and tj86430
3 should be at 5 in the second diagram, and white gets a ko. Black can do better than that.
$$B Black to play $$ ----------------------- $$ . . . 8 5 . 2 1 . O . . $$ . . 7 6 4 O 9 3 . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .
[go]$$B Black to play $$ ----------------------- $$ . . . 8 5 . 2 1 . O . . $$ . . 7 6 4 O 9 3 . O X . $$ . X . X X X O O O X X . $$ . . . . . . X . X . . . $$ . . . . . . . X . . . . $$ . . . . . . . . . . . .[/go]
defeats your 
...
@ 1 
@1
still ends up in ko.