Basically they are buildings from the catalogue stuck onto generic base sizes and then given groundwork treatment around them. I haven't put as much detail as I would for a 28mm version as it would just get in the way for gaming and be quite delicate.
There is enough there though to make it look convincing though.
One feature of a Japanese field is the raised beds, there are quite a few reasons for this which I won't go into now (a post all by itself!) but it certainly gives a definite feel for a gaming piece.
Also, orchards are grown over there with various fruit trees.
I'd like to get into 15mm gaming a bit more to allow for this sort of thing to be on the table without taking up the whole thing :-)
As ever, I'll leave you with some different shots.