I did not know that you had Japanese computers back then, but I remember speaking with a Bulgarian guy who told me that Bulgaria supplied computers to much of Eastern Europe - this guy was an IT GENIUS.
I think the MSX standard to which the Japanese computers belonged was the most widespread in the world those days except the United States, as says Wikipedia. MSX - Wikipedia, the free encyclopedia
One more feature I remember from their experience was that you could move through the text diagonally by pressing two arrow keys at once - very comfortable! In IBM PC - compatible computers you cannot!

I never seen any Bulgarian computer, although, Soviet-made computers were seen quite often. I also seen some East-German equipment such as Robotron printers and drives.
My first home computer was БК-0010-01 which at the time costed 600 rubles:

Im my case the case was gray:

Although it was not compatible with MSX and had a different architecture, it was heavily influenced by Yamahas in that its imbeeded Basic dialect was a truncated variant of that on the MSX computers. You can also see the two buttons for switching layouts here