Like you know i cannot find any movies that have it but i am sure you heard it before say Chuck Norris movie where he goes to Nam and during his stealth action you could hear Vietnamese made instrumental music (not vocal or not US music).
Perhaps this music or similar is used in Japanese ninja movies to it.
I wonder what those called and is there albums for it i been looking on youtube but all i find by keyword is soundtrack to Battlefield Vietnam video game with some old US vocal bands.
First 10 seconds of this song seems like a good match however what i need its more active and mysterious http://www.audiomicro.com/ethnic-emo...-music-1141787
Its made on instruments like this but sounds like an action movie music.