L19 Go Problem Championship: Round 5

Kirby · Post by **Kirby** » Sun Mar 19, 2017 8:23 pm

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!

EdLee · Post by **EdLee** » Sun Mar 19, 2017 11:35 pm

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]$$B $$---------------------- $$ . X . . . . O X X . | $$ . 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]

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]

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]

Kirby · Post by **Kirby** » Mon Mar 20, 2017 7:41 pm

@EdLee:

mongus · Post by **mongus** » Tue Mar 21, 2017 5:19 am

hyperpape · Post by **hyperpape** » Tue Mar 21, 2017 11:17 am

Problem 1

Kirby · Post by **Kirby** » Tue Mar 21, 2017 2:27 pm

mongus wrote:
Problem 1 :

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

@mongus:

Kirby · Post by **Kirby** » Tue Mar 21, 2017 2:28 pm

hyperpape wrote:Problem 1
Ko. Black takes first.

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

gamesorry · Post by **gamesorry** » Tue Mar 21, 2017 10:59 pm

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]

hyperpape · Post by **hyperpape** » Wed Mar 22, 2017 6:24 am

Problem 1 redux:

Kirby · Post by **Kirby** » Wed Mar 22, 2017 8:47 am

@gamesorry:

Kirby · Post by **Kirby** » Wed Mar 22, 2017 8:48 am

@hyperpape:

hyperpape · Post by **hyperpape** » Wed Mar 22, 2017 7:46 pm

Problem 2:

Kirby · Post by **Kirby** » Wed Mar 22, 2017 9:45 pm

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

$$Bc
$$ --------------------
$$ . X . 5 4 . O X X . |
$$ . 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 . . |
$$ . . . . . . . . . . |
Click Here To Show Diagram Code
[go]$$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 made a false eye after B connects. I had to set up a board to see that there's a throw-in.

@hyperpape:

Hint:

hyperpape · Post by **hyperpape** » Thu Mar 23, 2017 8:07 am

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

Kirby · Post by **Kirby** » Thu Mar 23, 2017 9:56 am

@hyperpape:

Life In 19x19

L19 Go Problem Championship: Round 5

L19 Go Problem Championship: Round 5

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Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5

Re: L19 Go Problem Championship: Round 5