Life In 19x19 • Yithril vs. Magicwand

Page 6 of 6

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 2:32 am

by The Intrepid

@ topazg

Wouldn't White then continue with 7, forcing Black into a less advantageous ko than before?

$$W
$$ --------------------------
$$ | . 4 . . . . . . . . .
$$ | 5 1 2 X . . . . . . .
$$ | 8 3 7 X O . O . . . .
$$ | 9 X X O . . . . . X .
$$ | 6 X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 2:43 am

by topazg

@intrepid:

Quite right. I was thinking Black has miai, but he should probably take :w7:

in yours first.

$$W
$$ --------------------------
$$ | . 4 . a . . . . . . .
$$ | 5 1 2 X . . . . . . .
$$ | . 3 6 X O . O . . . .
$$ | . X X O . . . . . X .
$$ | . X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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

Because of "a", I'm struggling to see how White can restrict Black's liberties enough to create a ko..

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 3:00 am

by The Intrepid

@topazg

This should work, it seems:

$$W
$$ --------------------------
$$ | . 4 . 7 . . . . . . .
$$ | 5 1 2 X 8 9 . . . . .
$$ | . 3 6 X O . O . . . .
$$ | . X X O . . . . . X .
$$ | . X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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

$$B
$$ --------------------------
$$ | . X . O 1 . . . . . .
$$ | O O X X X O . . . . .
$$ | . O X X O . O . . . .
$$ | 2 X X O . . . . . X .
$$ | . X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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

Edit: Never mind, this does not work ... hmm

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 3:02 am

by topazg

@Intrepid:

Are you sure?

$$B
$$ --------------------------
$$ | a X b O 1 . . . . . .
$$ | O O X X X O . . . . .
$$ | . O X X O . O . . . .
$$ | 2 X X O . . . . . X .
$$ | 3 X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

Click Here To Show Diagram Code: [go]$$B $$ -------------------------- $$ | a X b O 1 . . . . . . $$ | O O X X X O . . . . . $$ | . O X X O . O . . . . $$ | 2 X X O . . . . . X . $$ | 3 X O O . . . . . . . $$ | . O . . . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$[/go]

Now what? White can't play at "a", and so after "b" Black is unconditionally alive?

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 3:03 am

by The Intrepid

Just realized this myself

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 3:34 am

by topazg

Hehe

$$B
$$ --------------------------
$$ | . X 2 3 . . . . . . .
$$ | O O X X 4 . . . . . .
$$ | a O 1 X O . O . . . .
$$ | 5 X X O . . . . . X .
$$ | . X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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

Even this is obviously alive, as White can't play at "a", and Black can.

EDIT: ok, an obvious ko:

$$B
$$ --------------------------
$$ | . X 2 3 . . . . . . .
$$ | O O X X 6 . . . . . .
$$ | 7 O 1 X O . O . . . .
$$ | 4 X X O . . . . . X .
$$ | 5 X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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

However, this is a two step approach ko, so timing is difficult. I can't see a better way for White, but there may be one (mitsun is a lot stronger than I am).

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 3:47 am

by The Intrepid

Yeah, I can't see anything better than the approach ko either. Looks like this is Black's best option.

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 5:53 am

by Magicwand

R15 PEEP

Re: Yithril vs. Magicwand

Posted: Mon Aug 27, 2012 12:19 pm

by mitsun

Topazg & Intrepid

I think the problem is symmetric -- B can play either way and W gets an approach move ko. In your sequence, W does not have to prevent B from playing (a) or throw-in to force B to play (a).

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

$$W
$$ --------------------------
$$ | . X . 2 5 . . . . . .
$$ | O O X X 1 . . . . . .
$$ | . O X X O . O . . . .
$$ | 3 X X O . . . . . X .
$$ | 4 X O O . . . . . . .
$$ | . O . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$

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