Katlaughing makes and interesting point.

In the thread I started I wondered if Seven Samurai was a western, it really has all of the elements except for location and language.

I think a movie genre, more than anything else is defined by the antagonist
Treasure of Sierra Madre, one of my favorite movies, does not have the feel of a western. The plot is not straightforward and the antagonist ends up being Dobbs' animal nature rather than indians or rustlers or rail road barons.