Soleil Rouge has always been of my favorite westerns thanks to the great international cast. Are there any other "sushi-westerns" ? (not Japanese westerns, but "Western" westerns with Japanese elements.
Red Sun The Stranger in Japan The Five Man Army White, the Yellow, and the Black
The following do not feature Japanese elements, but rather Japanese playing Mexicans! In fact two famous samurai actors, Toshiro Mifune and Tatsuya Nakadai both played Mexicans. They are:
its chinese not japanese style buy "Là dove non batte il sole" aka "blood money" with lee van cleef may be what you are looking for. (not in the same class as red sun tho)
The Stranger and the Gunfighter (aka Blood Money) The Fighting Fists of Shanghai Joe Return of Shanghai Joe Three Musketeers of the West Shanghai Noon Walk Like a Dragon
The Spaghetti Western 'Oggi a me... domani a te!' may not actually have a literal Japanese character but it does have one of the greatest Japanese actors, Nakadai Tatsuya, as the villain James Elfrego.
Nakadai is also in another Western, this time as a Japanese character, the film is called 'East Meets West' but I haven't seen it. There seems to be a few clips of it on YouTube though.
P.S. I'm not sure why everyone is stating films that are Chinese influenced. There are many differences between China and Japan.
"There are many differences between China and Japan"
Indeed. Apart from the Chinese influence on Japan, they are actually non-related (well atleast on a close level, all cultures are related) cultures. Japan is closer, culturally, to Korea and the other Altaic cultures than it is to China.
There is something very Japanese about "Shane". Shane is like a samurai. No past, no future. Before "Shane", there was no western quite like it; a gunfighter who wants to put his gun away yet winds up helpings strangers with his gun skill for motives he never clearly articulates.
I wonder if "The Seven Samurai" owes something to "Shane".
The movie pilot "Kung Fu" from 1972 fits the bill, if you don't mind Chinese flavor rather than Japanese. It's a great stand-alone Western with Asian influence.