Definitely. But if the Japanese usage is as a proper noun, you can translate it and still use it as such. We do this with native words all the time - lower-case

Definitely. But if the Japanese usage is as a proper noun, you can translate it and still use it as such. We do this with native words all the time - lower-case agile vs capital Agile, for instance. The question isn't whether or not we should proper-noun-ify things as much as whether or not we are served by doing so with a foreign word -- the meaning of which isn't immediately clear to an uninitiated audience.