Japanese products: straight copies, developed versions or pure originals? A difficult question to which I don't think any exact, definitive answers can be provided. I can only refer to what I have observed over the years, and that is in the realms of communications receivers, particularly valved ones for the approximate period 1965 - 1985.
Take the covers off any Japanese radio of that type and compare what you see to a similar product in an all-American design: the similarities in construction are remarkable - especially to our British eyes which are more familiar with the mechanical and electrical design of products from firms such as Eddystone, Pye, GEC, Racal et al. And notice the valves: 6BA6, 6AJ8, 6BX6, 6BE6, 12AX7, 6BM8, for example, where in a European design we would expect to find EF93, ECH81, EF80, EK90, ECC81, ECL82 respectively. Under the chassis we find a component wiring & layout which again looks remarkably similar. For example, Hammurlund and Hallicrafters have produced some excellent comms. receivers during this period and it is clear that several Japanese radios were based on those designs. To what extent are they 'copies' and indeed, just how much involvement, if any, did such American companies have in those Japanese designs? How did all this come about? A number of possibilities spring to my mind. One, post WW2, much (but not all) of Japan's infrastructure was re-built by the USA: hence their dual systems of electrical power distribution: 115 v.a.c. 60 Hz and 230 v.a.c. 50 Hz. Two, a lot of American companies established manufacturing plants in Japan: Hewlett-Packard being one good example. Three: the largest demand for Amateur Radio products in the world, for the period stated, was in the USA: hence, the use of components - such as valves - that are available within the USA. Off-hand, I cannot think of any classic U.K. comms. radio designs of which Japan produced 'near look-alikes': can you?
To me, one thing is quite clear: the Japanese may or may not be copiers of established products, but they certainly seem to fit my understanding of lateral thinkers. Perhaps that is because the Eastern cultures are far less competitive than those of the West: "this is our design" as opposed to "I designed that". I wonder why such a difference in the two approaches to thinking evolved over the many centuries: any ideas?
Just an attempt to try to keep this fascinating thread on topic.