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 Post subject: Exciting problem to decide a game #1 Posted: Mon Dec 05, 2011 3:02 pm
 Judan

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The position below is adapted from a recent game of mine. White has just passed, so it is black's move. White could have played j15 as the dame were being filled to fix the bad aji of the 2 black stones inside white's area, but then he would have lost by 0.5 points (Japanese rules). But bad aji won't win the game for black, he must find a sequence that works against any white resistance. The stakes could not be higher!

Note that a ko can be assumed as a success for black, as he only needs to gain 1 point to win the game, and there were indeed threats on the rest of the board. I have studied this position extensively and I believe black can win, though it is possible I missed something. This is a hard problem, to solve it without playing it out I think you need to be a high dan. I will give a few hints below, and post my solution later.

`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . . O X X . . . , . . . |\$\$ | . . X O . . . . . X O X . . . . . . . |\$\$ | . . X O . . . . . . O X . . . . . . . |\$\$ | . . X O . . . . O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

Hints:
1) Add a second stone and sacrifice both.
2) That white has a dango rather than eye in the lower left is relevant.
3) You need to take your shoes off to count the snapbacks.

 This post by Uberdude was liked by: cyclops
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 Post subject: Re: Exciting problem to decide a game #2 Posted: Mon Dec 05, 2011 5:49 pm
 Tengen

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i looked at it for 3 min and can not find any... i will try later when i have more time.

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 Post subject: Re: Exciting problem to decide a game #3 Posted: Mon Dec 05, 2011 6:12 pm
 Tengen

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are you sure that there is answer to this question???
i spent few more minute..and i dont see anything but aji.

_________________
"The more we think we know about
The greater the unknown"

Words by neil peart, music by geddy lee and alex lifeson

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 Post subject: Re: Exciting problem to decide a game #4 Posted: Mon Dec 05, 2011 7:41 pm
 Gosei

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I just see dead ends as well. Albeit, I will now look at the hints.

Quite boring:
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . . O X X . . . , . . . |\$\$ | . . X O . . 7 5 3 X O X . . . . . . . |\$\$ | . . X O . . 6 4 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . 7 . O X X . . . , . . . |\$\$ | . . X O . . . 6 3 X O X . . . . . . . |\$\$ | . . X O . . 5 4 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

...Guess I was nowhere close

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 Post subject: Re: Exciting problem to decide a game #5 Posted: Mon Dec 05, 2011 7:57 pm
 Lives in sente

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Without using the hint after a few minutes this 7kyu came up with:
`[go]\$\$Bc\$\$ +-----------------------------\$\$ | . . . . X O . . . O X . . . \$\$ | . . . . X O 8 . . O X . . . \$\$ | . . X X X O 7 . . O X . . . \$\$ | . . X O O 3 4 . . O X X . . \$\$ | . . X O . 5 . 2 . X O X . . \$\$ | . . X O . 6 1 . . . O X . . \$\$ | . . X O . . . . O O O X . . \$\$ | . X X O . 9 0 X O X X X . . \$\$ | . X O O . O O O X X . . . . \$\$ | . X O O O X X X . , . . . . \$\$ | . X O O O X . . . . . . . . \$\$ | . X X X X X . . . . . . . . \$\$ | . . . . . . . . . . . . . .[/go]`

`[go]\$\$Bc\$\$ +---------------------------\$\$ | . . . . X O . . . O X . . \$\$ | . . . . X O O . . O X . . \$\$ | . . X X X O X . . O X . . \$\$ | . . X O O X O 4 . O X X . \$\$ | . . X O . X 3 O . X O X . \$\$ | . . X O 7 O X . 2 . O X . \$\$ | . . X O . . 5 1 O O O X . \$\$ | . X X O . X O X O X X X . \$\$ | . X O O 6 O O O X X . . . \$\$ | . X O O O X X X . , . . . \$\$ | . X O O O X . . . . . . . \$\$ | . X X X X X . . . . . . . \$\$ | . . . . . . . . . . . . .[/go]`

edit: In the next post MagicWand exposes my mistake quite clearly. So skip my post please.

Last edited by cyclops on Wed Dec 07, 2011 6:10 am, edited 1 time in total.
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 Post subject: Re: Exciting problem to decide a game #6 Posted: Mon Dec 05, 2011 8:03 pm
 Tengen

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cyclops wrote:
Without using the hint after a few minutes this 7kyu came up with:
`[go]\$\$Bc\$\$ +-----------------------------\$\$ | . . . . X O . . . O X . . . \$\$ | . . . . X O 8 . . O X . . . \$\$ | . . X X X O 7 . . O X . . . \$\$ | . . X O O 3 4 . . O X X . . \$\$ | . . X O . 5 . 2 . X O X . . \$\$ | . . X O . 6 1 . . . O X . . \$\$ | . . X O . . . . O O O X . . \$\$ | . X X O . 9 0 X O X X X . . \$\$ | . X O O . O O O X X . . . . \$\$ | . X O O O X X X . , . . . . \$\$ | . X O O O X . . . . . . . . \$\$ | . X X X X X . . . . . . . . \$\$ | . . . . . . . . . . . . . .[/go]`

`[go]\$\$Bc\$\$ +---------------------------\$\$ | . . . . X O . . . O X . . \$\$ | . . . . X O O . . O X . . \$\$ | . . X X X O X . . O X . . \$\$ | . . X O O X O 4 . O X X . \$\$ | . . X O . X 3 O . X O X . \$\$ | . . X O 7 O X . 2 . O X . \$\$ | . . X O . . 5 1 O O O X . \$\$ | . X X O . X O X O X X X . \$\$ | . X O O 6 O O O X X . . . \$\$ | . X O O O X X X . , . . . \$\$ | . X O O O X . . . . . . . \$\$ | . X X X X X . . . . . . . \$\$ | . . . . . . . . . . . . .[/go]`

i think your 1 wont work
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . . O X X . . . , . . . |\$\$ | . . X O . . . . . X O X . . . . . . . |\$\$ | . . X O . . 1 . . . O X . . . . . . . |\$\$ | . . X O . . 2 . O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

_________________
"The more we think we know about
The greater the unknown"

Words by neil peart, music by geddy lee and alex lifeson

 This post by Magicwand was liked by: cyclops
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 Post subject: Re: Exciting problem to decide a game #7 Posted: Tue Dec 06, 2011 12:40 am
 Tengen

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Loons wrote:
I just see dead ends as well. ...
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . 7 . O X X . . . , . . . |\$\$ | . . X O . . . 6 3 X O X . . . . . . . |\$\$ | . . X O . . 5 4 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

...Guess I was nowhere close

I think that Loons is on the right track, only one point off on the last move.

`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . 0 . O X . . . . . . . . |\$\$ | . . . . X O . 8 . O X . . . . . . . . |\$\$ | . . X X X O . 9 . O X . . . . . . . . |\$\$ | . . X O O . . . 7 O X X . . . , . . . |\$\$ | . . X O . . . 6 3 X O X . . . . . . . |\$\$ | . . X O . . 5 4 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

I'm not sure where to go here, but it feels right.
Maybe this?

`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . O 2 O X . . . . . . . . |\$\$ | . . . . X O 3 O 1 O X . . . . . . . . |\$\$ | . . X X X O . X . O X . . . . . . . . |\$\$ | . . X O O . . . X O X X . . . , . . . |\$\$ | . . X O . . . O X X O X . . . . . . . |\$\$ | . . X O . . X O O . O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

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 Post subject: Re: Exciting problem to decide a game #8 Posted: Tue Dec 06, 2011 11:27 am
 Judan

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Loons wrote:
I just see dead ends as well. Albeit, I will now look at the hints.

...Guess I was nowhere close

You were on the right track, but seemed to give up before it was clear what happened. Keep going, the main lines are 20-25 moves long.

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 Post subject: Re: Exciting problem to decide a game #9 Posted: Tue Dec 06, 2011 5:00 pm
 Lives in sente

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Uberdude wrote:
You were on the right track, but seemed to give up before it was clear what happened. Keep going, the main lines are 20-25 moves long.

So I continued from Loons last diagram:

edit: so loons, in his latter diagram, better moves to H14

Last edited by cyclops on Tue Dec 06, 2011 7:38 pm, edited 1 time in total.
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 Post subject: Re: Exciting problem to decide a game #10 Posted: Tue Dec 06, 2011 7:06 pm
 Oza

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I think loons was closest with this diagram. But not yet spot on.
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

I think Black wants to play in this order. If , Black will play instead of "a". What now? White does not seem able to escape without allowing Black to peep with "b" and cut off the three White stones. For example if , Black drives down and then plays "b" after White connects. This makes miai of "c" and "d".
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . 9 O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O c b . 3 O X X . . . , . . . |\$\$ | . . X O . . . a 4 X O X . . . . . . . |\$\$ | . . X O . . 6 d 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

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 This post by ez4u was liked by 2 people: cyclops, Uberdude
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 Post subject: Re: Exciting problem to decide a game #11 Posted: Wed Dec 07, 2011 12:09 am
 Beginner

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ez4u wrote:
I think loons was closest with this diagram. But not yet spot on.
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

I think Black wants to play in this order. If , Black will play instead of "a". What now? White does not seem able to escape without allowing Black to peep with "b" and cut off the three White stones. For example if , Black drives down and then plays "b" after White connects. This makes miai of "c" and "d".
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . 9 O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O c b . 3 O X X . . . , . . . |\$\$ | . . X O . . . a 4 X O X . . . . . . . |\$\$ | . . X O . . 6 d 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

And why not 4 at h14?

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 Post subject: Re: Exciting problem to decide a game #12 Posted: Wed Dec 07, 2011 1:12 am
 Oza

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yeah wrote:
ez4u wrote:
I think loons was closest with this diagram. But not yet spot on.
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

I think Black wants to play in this order. If , Black will play instead of "a". What now? White does not seem able to escape without allowing Black to peep with "b" and cut off the three White stones. For example if , Black drives down and then plays "b" after White connects. This makes miai of "c" and "d".
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . 9 O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O c b . 3 O X X . . . , . . . |\$\$ | . . X O . . . a 4 X O X . . . . . . . |\$\$ | . . X O . . 6 d 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

And why not 4 at h14?

If , then forces . After the exchange of and , makes miai of "a" and "b" (Black has the atari at "c" if White connects against "b").
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . b O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O a 9 . X O X X . . . , . . . |\$\$ | . . X O . . . . 6 X O X . . . . . . . |\$\$ | . . X O . . c 4 O 8 O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

_________________
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

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 Post subject: Re: Exciting problem to decide a game #13 Posted: Wed Dec 07, 2011 1:29 am
 Beginner

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ez4u wrote:
yeah wrote:
ez4u wrote:
I think loons was closest with this diagram. But not yet spot on.
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

I think Black wants to play in this order. If , Black will play instead of "a". What now? White does not seem able to escape without allowing Black to peep with "b" and cut off the three White stones. For example if , Black drives down and then plays "b" after White connects. This makes miai of "c" and "d".
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . 9 O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O c b . 3 O X X . . . , . . . |\$\$ | . . X O . . . a 4 X O X . . . . . . . |\$\$ | . . X O . . 6 d 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

And why not 4 at h14?

If , then forces . After the exchange of and , makes miai of "a" and "b" (Black has the atari at "c" if White connects against "b").
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . b O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O a 9 . X O X X . . . , . . . |\$\$ | . . X O . . . . 6 X O X . . . . . . . |\$\$ | . . X O . . c 4 O 8 O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

Something is weird with that diagram. Stones missing.

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 Post subject: Re: Exciting problem to decide a game #14 Posted: Wed Dec 07, 2011 4:07 am
 Oza

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yeah wrote:
Something is weird with that diagram. Stones missing.

Here it is with all the moves. I thought it was OK. Is something missing? If so, where?
`[go]\$\$c Black to play\$\$ ---------------------------------------\$\$ | . . . . X O . . b O X . . . . . . . . |\$\$ | . . . . X O . . 7 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O a 9 . 3 O X X . . . , . . . |\$\$ | . . X O . . . . 6 X O X . . . . . . . |\$\$ | . . X O . . c 4 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

_________________
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

 This post by ez4u was liked by: illluck
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 Post subject: Re: Exciting problem to decide a game #15 Posted: Wed Dec 07, 2011 4:27 am
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Hups I got confused.

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 Post subject: Re: Exciting problem to decide a game #16 Posted: Wed Dec 07, 2011 6:08 am
 Lives in sente

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I like Dave's solution a lot. Elegant and straightforward. Especially his is brilliant. To be sure I tried different 's. at H14 or at H16 both fail smoothly.
Statistically I am wrong and I apologize for disturbing this discussion of dans but it seems my previous post shows an alternative for Dave's at H15. Would anyone point out my mistake(s)?
edited after ezru reply: indeed it is more complex and indeed possibly wrong

Last edited by cyclops on Wed Dec 07, 2011 8:14 am, edited 1 time in total.
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 Post subject: Re: Exciting problem to decide a game #17 Posted: Wed Dec 07, 2011 6:18 am
 Oza

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cyclops wrote:
I like Dave's solution a lot. Elegant and straightforward. Especially his is brilliant. To be sure I tried different 's. at H14 or at H16 both fail smoothly.
Statistically I am wrong and I apologize for disturbing this discussion of dans but it seems my previous post shows an alternative for Dave's at H15. Would anyone point out my mistake(s)?

It wasn't clear to me that Black has a clean finish if White answers simply H14. I could be wrong though. It just seemed more complex.

_________________
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

 This post by ez4u was liked by: cyclops
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 Post subject: Re: Exciting problem to decide a game #18 Posted: Wed Dec 07, 2011 6:01 pm
 Judan

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I had missed the of Dave's solution, and it does indeed seem to work rather cleanly. But there is this white almost-resistance (although 6 is ugly it does prolong death the most):

`[go]\$\$c Almost-resistance\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . 7 6 O X . . . . . . . . |\$\$ | . . X X X O . . 5 O X . . . . . . . . |\$\$ | . . X O O . . 0 3 O X X . . . , . . . |\$\$ | . . X O . . . 9 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

(If 4 connects at 5 then black plays 4 for a snapback)

`[go]\$\$B11 Almost-resistance part 2\$\$ ---------------------------------------\$\$ | . . . . X O 7 6 . O X . . . . . . . . |\$\$ | . . . . X O . X O O X . . . . . . . . |\$\$ | . . X X X O . 1 X O X . . . . . . . . |\$\$ | . . X O O 5 3 O X O X X . . . , . . . |\$\$ | . . X O . . . X O . O X . . . . . . . |\$\$ | . . X O . . 4 2 O O O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

My solution was as the h15 net: it does work too though with rather more and longer variations. If white answers the h15 net with h14 black can still win, and I would encourage you to keep exploring that way as there is a rather exqusite double snapback as your prize at the end of one line

A few comments on cyclop's sgf, which shared a few sequences with my solution but had a few mistakes/gaps:

`[go]\$\$c (10 at 8)\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . a 6 O X . . . . . . . . |\$\$ | . . X O O b . 7 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . 9 2 8 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

At this position cyclops cut at b, but a kills in a one-way-street as below ( at succumbs to the throw in at 3).

`[go]\$\$c Swifter blow\$\$ ---------------------------------------\$\$ | . . . . X O 8 6 3 O X . . . . . . . . |\$\$ | . . . . X O 5 2 4 O X . . . . . . . . |\$\$ | . . X X X O 7 1 O O X . . . . . . . . |\$\$ | . . X O O 9 . X X O X X . . . , . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

You showed this sequence:

`[go]\$\$c Black mistake and then white mistake\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . b 7 O X . . . . . . . . |\$\$ | . . X O O c a 6 5 O X X . . . , . . . |\$\$ | . . X O . . 9 3 4 X O X . . . . . . . |\$\$ | . . X O . . 0 8 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

After and black a then white b, but white need not save the stone at b and can simply connect at c: then all white's groups are safe and black capturing one stone is only 1 eye so dead inside. So rewinding a few moves, black should play as below for a lovely connect-and-die (11 at a):

`[go]\$\$c Correct for black\$\$ ---------------------------------------\$\$ | . . . . X O . . a O X . . . . . . . . |\$\$ | . . . . X O . . 9 O X . . . . . . . . |\$\$ | . . X X X O . . 7 O X . . . . . . . . |\$\$ | . . X O O . . 6 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . 8 2 0 O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

Given that the above succeeds for black, white can try as below (note that Dave's solution prevents white doing this as the exchange of 9 for 10 in the first diagram (3 for 6 here) is after white plays 8 here):

`[go]\$\$c Strong white resistance\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . 0 8 O X . . . . . . . . |\$\$ | . . X X X O . 9 7 O X . . . . . . . . |\$\$ | . . X O O . . 6 5 O X X . . . , . . . |\$\$ | . . X O . . . 3 4 X O X . . . . . . . |\$\$ | . . X O . . . . 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

White lives on top (if white doesn't play black plays there), but black cut in sente so makes a seki. This is why I said the dango not eye in the lower left was relevant. Dave's solution is better in that it doesn't need this.

`[go]\$\$c contd. 3 at h16\$\$ ---------------------------------------\$\$ | . . . . X O . 8 . O X . . . . . . . . |\$\$ | . . . . X O . O O O X . . . . . . . . |\$\$ | . . X X X O 2 X X O X . . . . . . . . |\$\$ | . . X O O 7 1 3 X O X X . . . , . . . |\$\$ | . . X O . . . X O 6 O X . . . . . . . |\$\$ | . . X O . . . 5 O 4 O X . . . . . . . |\$\$ | . . X O . . . X O O O X . . . . . . . |\$\$ | . X X O . 9 . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

So that's pretty much covered the variations following white 4 at a, so how about the sub-problem of black to play below. Despite what seems like the sub-optimal he can still win.

`[go]\$\$c What now?\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . . O X X . . . , . . . |\$\$ | . . X O . . . 3 a X O X . . . . . . . |\$\$ | . . X O . . . 4 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

 This post by Uberdude was liked by 2 people: illluck, RBerenguel
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 Post subject: Re: Exciting problem to decide a game #19 Posted: Fri Dec 09, 2011 4:41 am
 Lives in sente

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public answer to previous post, hidden to save space
Uberdude wrote:
..................
My solution was as the h15 net: it does work too though with rather more and longer variations. If white answers the h15 net with h14 black can still win, and I would encourage you to keep exploring that way as there is a rather exqusite double snapback as your prize at the end of one line
.......................
So that's pretty much covered the variations following white 4 at a, so how about the sub-problem of black to play below. Despite what seems like the sub-optimal he can still win.

`[go]\$\$c What now?\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . . . O X . . . . . . . . |\$\$ | . . X O O . . . . O X X . . . , . . . |\$\$ | . . X O . . . 3 a X O X . . . . . . . |\$\$ | . . X O . . . 4 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

This diagram I have been studying since I hinted Loons to move his a in his last diagram. I´ll give it another try the coming days, I really want to find your jewels.
Uberdude wrote:
A few comments on cyclop's sgf, which shared a few sequences with my solution but had a few mistakes/gaps:
......
You showed this sequence:

`[go]\$\$c Black mistake and then white mistake\$\$ ---------------------------------------\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . . . X O . . . O X . . . . . . . . |\$\$ | . . X X X O . b 7 O X . . . . . . . . |\$\$ | . . X O O c a 6 5 O X X . . . , . . . |\$\$ | . . X O . . 9 3 4 X O X . . . . . . . |\$\$ | . . X O . . 0 8 2 . O X . . . . . . . |\$\$ | . . X O . . . 1 O O O X . . . . . . . |\$\$ | . X X O . . . X O X X X . . . . . . . |\$\$ | . X O O . O O O X X . . . . . . . . . |\$\$ | . X O O O X X X . , . . . . . , . . . |\$\$ | . X O O O X . . . . . . . . . . . . . |\$\$ | . X X X X X . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . , . . . . . , . . . . . , . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ | . . . . . . . . . . . . . . . . . . . |\$\$ ---------------------------------------[/go]`

After and black a then white b, but white need not save the stone at b and can simply connect at c: then all white's groups are safe and black capturing one stone is only 1 eye so dead inside. So rewinding a few moves, black should play as below for a lovely connect-and-die (11 at a):
.................

I assumed that capturing one white stone in sente would give black the decisive one point gain. Waking up this morning it occurred to me that for the score it does not matter whether W's inside stone are on the board or in the prisoners bin. Black needs to survive at least one stone inside. That explains my mistake above. That what you get when kyu's start interfering with dan problems .
Your other remarks on my variations are also very much to the point. I really appreciated the expert feedback.

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 Post subject: Re: Exciting problem to decide a game #20 Posted: Fri Dec 09, 2011 5:40 pm
 Lives in sente

Posts: 801
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`[go]\$\$Bc\$\$ +---------------------------\$\$ | . . . . X O . . . O X . . \$\$ | . . . . X O . 9 . O X . . \$\$ | . . X X X O . . . O X . . \$\$ | . . X O O . . . . O X X . \$\$ | . . X O . . . 3 7 X O X . \$\$ | . . X O . . 5 4 2 . O X . \$\$ | . . X O . . 6 . O O O X . \$\$ | . X X O . . 8 . O X X X . \$\$ | . X O O . O O O X X . . . \$\$ | . X O O O X X X . , . . . \$\$ | . X O O O X . . . . . . . \$\$ | . X X X X X . . . . . . . \$\$ | . . . . . . . . . . . . .[/go]`

6 and 8 are forced. Next, because he wins any ko, black 9 captures the top right. No double snapback needed.

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