The Japanese don't tend to use a "one-cup measure" in the way we do, as it is really a rather antiquated and unwieldy system. However, that said, when they do, yes, it tends to be 200 mL, rather than the Western 250 mL.

If you need help with amounts/ingredients, please feel free to e-mail me (I think it's in my profile) or post the question here. I will try to help if I can. I spent two years "translating" recipes and cooking instructions, so I should be of some use.