Was there still consistent non-government controlled trade between coastal peoples in Japan and the mainland during this time? I would assume that an official policy of isolationism wouldn't be able to prevent all trade between these countries.

If some trade did exist, was it mostly done at a black market level, or did the government willingly just turn a blind eye as long as it was done below a certain scale?

What about trade with the Ainu? Were they considered an outside power to be isolated from in this regard as well?