I'm trying to play against simple online bot cosmi.net. I started playing about two days ago, so I'm a complete beginner, and even the easiest version on 9x9 board is really hard for me to beat. This is in fact the first time I managed to do that.
$$Wcm12
$$ ---------------------
$$ | . . . . . . . . . |
$$ | . . . . 4 3 . . . |
$$ | . . . . X O . . . |
$$ | . . . X . O . . . |
$$ | . . . . X O . . . |
$$ | . . . X . X O . . |
$$ | . . 1 2 . X O . . |
$$ | . . a . . 6 5 . . |
$$ | . . . . . . . . . |
$$ ---------------------
For some reason though, the bot marked black 17 as a bad move, and suggested to play at point "a" instead. Can anyone explain me why was that move marked as bad?