RE: computer-go: Defeating mirror Go

[<Michael.Collins@xxxxxxx>]

> Thomas P. Johnson Wrote:
>
> You don't even need super-ko (or any ko) to defeat mirror go through the
> center point.  Here's a toughie for black:
>
> White to move.
>
>      A B C D E F G H J K L M N O P Q R S T
>   19 . . . . . . . . . . . . . . . . . . . 19
>   18 . . . . . . . . . . . . . . . . . . . 18
>   17 . . . . . . . . . . . . . . . . . . . 17
>   16 . . . . . # # # # # O O O O . . . . . 16
>   15 . . . . # O O O O O # # # # O . . . . 15
>   14 . . . . # O # # # . O O O # O . . . . 14
>   13 . . . . # O # . . . . . O # O . . . . 13
>   12 . . . . # O # . . # # . O # O . . . . 12
>   11 . . . . # O # . # . # . O # O . . . . 11
>   10 . . . . # O # . # # # . O # O . . . . 10
>    9 . . . . # O # . # . # . O # O . . . . 9
>    8 . . . . # O # . # # . . O # O . . . . 8
>    7 . . . . # O # . . . . . O # O . . . . 7
>    6 . . . . # O # # # . O O O # O . . . . 6
>    5 . . . . # O O O O # # # # # O . . . . 5
>    4 . . . . . # # # # O O O O O . . . . . 4
>    3 . . . . . . . . . . . . . . . . . . . 3
>    2 . . . . . . . . . . . . . . . . . . . 2
>    1 . . . . . . . . . . . . . . . . . . . 1
>      A B C D E F G H J K L M N O P Q R S T
>
> Of course, I think you have to fall back to super ko if black places the
> vertical line of stones that William suggested and the mirror is through
that
> line.
>
> -Tom J.
>

Don't all of these fall over?
Doesn't any board position starting with an unconditionally alive group
defeat mirror go?

To defeat any type of mirror go ( at least to defeat the mirror part as
opposed to winning the game ) all you need to do is play on a point of
reflection/rotation/both.

This would stop being mirror go as soon as someone plays this as it can't
be mirrored from that point on ( Surely this would be what GoDevil would do
playing against an opponent that could ONLY play mirror go )

( However, if there were an even number of rows/columns... )

Regards,
Mike...