I've heard from various people that trying to sell foreign products in Japan can be unusually interesting. Regulations can make it very difficult to open stores, never mind local factories, and there's a certain background level of xenophobia and exceptionalism which means that Japanese buyers only take foreign products seriously if their brand is seen as having high status.
Just because it's an open market in theory doesn't mean that it's open in practice.
On the opposite side, imports are comparatively exceedingly high (than say, if the yen were at 2 to the dollar), which fits their market just fine. Never underestimate their intelligence, always underestimate their knowledge.
Frank Delaney ~ Ireland