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 Post subject: L19 Go Problem Championship: Round 5
Post #1 Posted: Sun Mar 19, 2017 8:23 pm 
Judan

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Welcome to Round 5 of the L19 Go Problem Championship.

All problems are black to play. As usual, provide your solutions either via hide tags, or direct private message to me.

Problem 1 (3 points)
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ | . O . X . . . . . .
$$ | . X O X X X O . O .
$$ | . X X O O O O . . .
$$ | O O O , . . . . . ,
$$ | . . . . . . . . . .[/go]



Problem 2 (6 points)
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X . . . . O X X . |
$$ . X O . . X . O X . |
$$ . X O . O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]



Problem 3 (9 points)
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . . . . . O X .
$$ | . X . X O . O . . O X .
$$ | . X . . X . . . O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]



Have fun! :salute:

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Post #2 Posted: Sun Mar 19, 2017 11:35 pm 
Judan
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Click Here To Show Diagram Code
[go]$$B
$$ --------------------
$$| . O . X . . . . . .
$$| . X O X X X O . O .
$$| . X X O O O O . . .
$$| O O O , . . . . . ,
$$| . . . . . . . . . .[/go]
Click Here To Show Diagram Code
[go]$$B (a), (b) miai life
$$ --------------------
$$| . O a X . b . . . .
$$| 1 X O X X X O . O .
$$| . X X O O O O . . .
$$| O O O , . . . . . ,
$$| . . . . . . . . . .[/go]
Click Here To Show Diagram Code
[go]$$B ko for life
$$ --------------------
$$| . O 1 X . 3 . . . .
$$| 2 X O X X X O . O .
$$| . X X O O O O . . .
$$| O O O , . . . . . ,
$$| . . . . . . . . . .[/go]
Click Here To Show Diagram Code
[go]$$B ko for life
$$ --------------------
$$| . O X X . X . . . .
$$| O X . X X X O . O .
$$| 4 X X O O O O . . .
$$| O O O , . . . . . ,
$$| . . . . . . . . . .[/go]
Click Here To Show Diagram Code
[go]$$B
$$----------------------
$$ . X . . . . O X X . |
$$ . X O . . X . O X . |
$$ . X O . O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]
W lives:
Click Here To Show Diagram Code
[go]$$B :b5: at :wc:
$$----------------------
$$ . X . . 4 1 W X X . |
$$ . X O . 2 X 3 O X . |
$$ . X O 6 O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]
:study:
Click Here To Show Diagram Code
[go]$$B
$$----------------------
$$ . X . . 1 . O X X . |
$$ . X O . . X . O X . |
$$ . X O . O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]
:study:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . . . . . O X .
$$ | . X . X O . O . . O X .
$$ | . X . . X . . . O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #3 Posted: Mon Mar 20, 2017 7:41 pm 
Judan

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@EdLee:
Problem 1 is correct.

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #4 Posted: Tue Mar 21, 2017 5:19 am 
Dies with sente

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Problem 1 :

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

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #5 Posted: Tue Mar 21, 2017 11:17 am 
Tengen

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Problem 1
Ko. Black takes first.

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

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #6 Posted: Tue Mar 21, 2017 2:27 pm 
Judan

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mongus wrote:
Problem 1 :

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


@mongus:
Correct!

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #7 Posted: Tue Mar 21, 2017 2:28 pm 
Judan

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hyperpape wrote:
Problem 1
Ko. Black takes first.

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


@hyperpape:
Good work! Can you get better than ko, now?

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #8 Posted: Tue Mar 21, 2017 10:59 pm 
Lives with ko

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


2.

Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 5 3 4 . O X X . |
$$ . X O 2 1 X 6 O X . |
$$ . X O 7 O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


Variation: after B5, a and b miai
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 5 3 a . O X X . |
$$ . X O 2 1 X 4 O X . |
$$ . X O b O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


Variation:
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 4 3 6 . O X X . |
$$ . X O 2 1 X . O X . |
$$ . X O 5 O O O O X . |
$$ , X 7 X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


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



B3 & W4 fails:
Click Here To Show Diagram Code
[go]$$Bc 9=1
$$ --------------------
$$ . X 7 5 4 8 O X X . |
$$ . X O 2 1 X 6 O X . |
$$ . X O 3 O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


However, with B3 white has strong resistance:
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 7 4 8 9 O X X . |
$$ . X O 2 1 X 6 O X . |
$$ . X O 3 O O O O X . |
$$ , X 5 X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


(Cont'd)
Click Here To Show Diagram Code
[go]$$Wc
$$ --------------------
$$ . X X 2 3 X O X X . |
$$ . X . 1 X X O O X . |
$$ . X . X O O O O X . |
$$ , X X X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


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


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


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


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


3.
Ko:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 4 . 5 9 O X .
$$ | . X . X O . O 8 . O X .
$$ | . X . . X 2 1 0 O . X .
$$ | . . X . . 3 6 7 O O X .
$$ ------------------------[/go]


B5 fails:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 4 . 6 . O X .
$$ | . X . X O . O . . O X .
$$ | . X . . X 2 1 . O . X .
$$ | . . X . . 3 5 . O O X .
$$ ------------------------[/go]


W4 fails:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 8 . 9 0 b O X .
$$ | . X . X O 4 O 6 a O X .
$$ | . X . . X 2 1 c O 7 X .
$$ | . . X . . 3 5 . O O X .
$$ ------------------------[/go]


Variation:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 8 7 . 6 . O X .
$$ | . X . X O 4 O 9 . O X .
$$ | . X . . X 2 1 . O . X .
$$ | . . X . . 3 5 . O O X .
$$ ------------------------[/go]


Variation:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 6 . . . . O X .
$$ | . X . X O 4 O 7 . O X .
$$ | . X . . X 2 1 . O . X .
$$ | . . X . . 3 5 . O O X .
$$ ------------------------[/go]


Variation:
After 7, a and b miai
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 7 5 a 2 . O X .
$$ | . X . X O 4 O . b O X .
$$ | . X . . X 3 1 6 O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]


Variation:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 5 7 a 6 . O X .
$$ | . X . X O 4 O . b O X .
$$ | . X . . X 3 1 2 O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]


B3 fails
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 4 . 6 . O X .
$$ | . X . X O 3 O . . O X .
$$ | . X . . X 5 1 2 O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]


B fails
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 6 . 7 5 . O X .
$$ | . X . X O 4 O 3 . O X .
$$ | . X . . X 1 2 . O . X .
$$ | . . X . . . 8 . O O X .
$$ ------------------------[/go]


B fails
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 5 a . 6 . O X .
$$ | . X . X O 4 O 3 b O X .
$$ | . X . . X 1 2 . O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]


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

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #9 Posted: Wed Mar 22, 2017 6:24 am 
Tengen

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Problem 1 redux:
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ | c O a X . b . . . .
$$ | 1 X O X X X O . O .
$$ | . X X O O O O . . .
$$ | O O O , . . . . . ,
$$ | . . . . . . . . . .[/go]

a and b are miai. Black either makes an eye to the left of b or two eyes from captures at a and c.

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #10 Posted: Wed Mar 22, 2017 8:47 am 
Judan

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@gamesorry:
Problems 1 and 2 are correct.

For Problem 3, did you consider this?

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

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #11 Posted: Wed Mar 22, 2017 8:48 am 
Judan

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@hyperpape:

You've got it! Good work :tmbup:

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #12 Posted: Wed Mar 22, 2017 7:46 pm 
Tengen

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Problem 2:
This one was funny, at least if I've managed to get it right. It was pretty easy to see that a, b, and c fail, so I was looking at d.
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X . . . a O X X . |
$$ . X O c d X b O X . |
$$ . X O . O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


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


For the longest time, I had read this far, but couldn't see that :w6: made a false eye after B connects. I had to set up a board to see that there's a throw-in.

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #13 Posted: Wed Mar 22, 2017 9:45 pm 
Judan

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hyperpape wrote:
Problem 2:
This one was funny, at least if I've managed to get it right. It was pretty easy to see that a, b, and c fail, so I was looking at d.
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X . . . a O X X . |
$$ . X O c d X b O X . |
$$ . X O . O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


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


For the longest time, I had read this far, but couldn't see that :w6: made a false eye after B connects. I had to set up a board to see that there's a throw-in.


@hyperpape:
Did you consider this move?
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X . 4 . . O X X . |
$$ . X O 2 1 X . O X . |
$$ . X O 3 O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


Hint:
You are pretty close.

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #14 Posted: Thu Mar 23, 2017 8:07 am 
Tengen

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Kirby wrote:
@hyperpape:
[hide]Did you consider this move?
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X . 4 . . O X X . |
$$ . X O 2 1 X . O X . |
$$ . X O 3 O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


Not in detail. I think I figured that there weren't enough liberties. So the issue is this under the stones play?
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 3 O 4 5 O X X . |
$$ . X O O X X 2 O X . |
$$ . X O X O O O O X . |
$$ , X 1 X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


Maybe if we change the order of moves?
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 4 3 6 . O X X . |
$$ . X O 2 1 X . O X . |
$$ . X O 5 O O O O X . |
$$ , X 7 X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


White can try the throw in.
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 5 3 4 . O X X . |
$$ . X O 2 1 X 6 O X . |
$$ . X O . O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]


But we're back to Black being able to make the eye false.
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------
$$ . X 7 3 4 . O X X . |
$$ . X O 2 1 X 6 O X . |
$$ . X O 5 O O O O X . |
$$ , X . X X O , O X . |
$$ . X . . . O O X . . |
$$ . . . . X X X X . . |
$$ . . . . . . . . . . |[/go]

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #15 Posted: Thu Mar 23, 2017 9:56 am 
Judan

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@hyperpape:
Yup! The under-the-stones trick was the thing to watch out for, and you found it. Changing the order of moves fixes the problem, and solves it.

You're on a roll. :tmbup:

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #16 Posted: Thu Mar 23, 2017 8:02 pm 
Judan

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Since we started a bit late this week, I'll wait until about 24 hours from now to post solutions.

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #17 Posted: Fri Mar 24, 2017 6:33 am 
Tengen

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Problem 3

Hard to even know where to start here. Maybe with the right incursions, we can limit White to a dead eye-space near the marked points?
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . . . M M O X .
$$ | . X . X O . O M M O X .
$$ | . X . . X . . M O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]


The a and b points are jumping out at me.
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . . . . . O X .
$$ | . X . X O . O a . O X .
$$ | . X . . X ..b . O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]


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


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


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


Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 5 7 4 . O X .
$$ | . X . X O 3 O . 6 O X .
$$ | . X . . X . 1 2 O . X .
$$ | . . X . . . . . O O X .
$$ ------------------------[/go]



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

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #18 Posted: Fri Mar 24, 2017 6:44 pm 
Lives with ko

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Kirby wrote:
@gamesorry:
For Problem 3, did you consider this?

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


Oops, I overlooked that.

So after 2 B has to play 3, but after W4B5, W has 6 and 8
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 5 3 . . . O X .
$$ | . X . X O 4 O 2 . O X .
$$ | . X . . X 6 1 . O . X .
$$ | . . X . . 7 8 . O O X .
$$ ------------------------[/go]


Therefore, to prevent 6 and 8, B need to consider something like:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X 5 3 . . . O X .
$$ | . X . X O 4 O 2 . O X .
$$ | . X . . X 9 6 . O . X .
$$ | . . X . . 8 1 7 O O X .
$$ ------------------------[/go]


B still needs to be careful: B3 fails
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 6 . 4 8 O X .
$$ | . X . X O . O 3 5 O X .
$$ | . X . . X . 2 7 O . X .
$$ | . . X . . . 1 . O O X .
$$ ------------------------[/go]


Therefore, B3 should:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 3 . . . O X .
$$ | . X . X O . O 4 . O X .
$$ | . X . . X . 2 . O . X .
$$ | . . X . . . 1 5 O O X .
$$ ------------------------[/go]


(Please deduct at least half of the points even if this is correct.)

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #19 Posted: Fri Mar 24, 2017 11:13 pm 
Judan

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Solutions and updated leader board are given below.

Problem 1


Problem 2


Problem 3


Leaderboard
  1. gamesorry - 82
  2. Shaddy - 49
  3. Schachus - 43
  4. EdLee - 38
  5. dfan - 25
  6. Lanrose - 16
  7. hyperpape - 15
  8. jeromie - 13
  9. mongus - 10

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 Post subject: Re: L19 Go Problem Championship: Round 5
Post #20 Posted: Fri Mar 24, 2017 11:51 pm 
Lives with ko

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Ah, I excluded the correct answer in the beginning due to the following W2:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . X X X X . . .
$$ | . . . . X O O O O X X .
$$ | . . . X . 1 . . . O X .
$$ | . X . X O . O 2 . O X .
$$ | . X . . X a b . O . X .
$$ | . . X . . . c . O O X .
$$ ------------------------[/go]


a and b obviously do not work, but actually c works. However, playing c first doesn't work. Nice problem!


This post by gamesorry was liked by: Kirby
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