loplopsama said: Because most of the art is Western art, which isn't allowed on this board.
Not so much that it isn't allowed, but either the subject or artist has to be of 'far eastern' flavor to be relevant for this place.
Japanese(y) Subject: Because it may not be known well here. Japanese(y) Artist: Because it may not be easy to keep up with or even find them due to language barriers (though some artists also post at deviantART).