Handle the situation with as much diplomacy as possible once the issue has been brought up, sure. But I'll be fucked if I'm going to sit in a meeting while the presenter uses my slide containing a "chart I had laboured over for months" to illustrate his company's strategy, while passing it off as their own.
"We weren’t sure if we should feel insulted or complimented, but after a few deep breaths (and a lot of kicking under the table by my head of business development) my smart VP of business development used it as an opportunity to point out how honored we were that there was an obvious strategic alignment between the two companies."
And there's an example of the diplomacy I was speaking of. I'd be fine putting a spin like that on it if required, for the sake of maintaining the relationship. But no way would I sit there and smile without saying a word.
In that situation they handled it really poorly and both sides lost an incredibly amount of face. My understanding of cultural stuff in Asia is above average but not complete: I do know enough, though, to say that a continued business relationship was an incredibly lucky outcome all round.
I would tend to agree, but I guess my definition of diplomacy includes salvaging situations. My kind of diplomacy isn't all roses and puppies.
Half my family is Asian (though not Japanese), I have a personal interest in Japanese culture and I'm generally aware of the cultural differences between East and West. Irrespective, I still would not sit tight in a meeting and smile while someone passes off my work as their own, regardless of how much face is at stake. I wouldn't much enjoy living with myself after such an episode.
I used to work as a translator/interpreter, among other duties, at a technology incubator in central Japan. Technical interpreters are expensive -- the best have hourly rates comparable to lawyers. They are paid that much because they bring in far more than their hourly in business deals saved from disastrous miscommunication. If your interpreter is trying to wave you off a topic, you might consider taking the advice you are paying so dearly for. (Incidentally, we're told that the canon of professional ethics requires translating every word without failure, so "You really don't want to say that!" should be a pretty big red flag to you that you are about to step in something.)