Very, very few foreign cars are imported into Japan. More than in Korea, but still a miniscule number. Japan has a large auto industry, and has been one of the most densely populated countries on Earth for hundreds of years. Put a fecund, industrious society on only about 100,000 sq km of land, with few natural resources, and the result is Japan. Except in the most rural inaka areas, and probably Nagoya, a car is not a necessity. In fact, in large cities, you can only register a car if you have proof of a parking space. Everyone else takes the train or city bus. And most cars in Japan are kei cars, anyway, because the country is so damn crowded!
From the data I have, in 2015, about 5 million domestic passenger vehicles were sold in Japan, with 1.9 million of those (about three-eighths) being Kei cars. Meanwhile, 328,600 foreign cars were sold in Japan that same year, for about a 6% market share. I've heard that Japan has trade barriers (non-tarriff) to which I am not privy.
Anyway, back to American cars. USDM cars are too big for Japanese roads, and the Detroit Big Three don't get that. Ford pulled out of Japan last year, in fact, and GM is having awful sales in the country. Any American car in Japan will be left-hand-drive, almost without exception.
When it comes to European cars, mass-market and entry-level vehicles are almost always right hand drive; a long time ago, foreign sports cars from Germany were generally in LHD (e.g. E36 M3), but now, more often than not they're RHD (e.g. F82 M4), with the exception of Porsche sports cars. They're still mostly in LHD.
Even some luxury cars and supercars are available in RHD. I've seen an RHD S63 coupe (C217, the next generation S-Class coupe that used to be the CL-Class), an RHD 458 Speciale, RHD 991 Turbo. The new AMG GT is available in LHD and RHD in Japan, whereas the SLS AMG was only available in LHD.
British supercars and luxury cars are generally in RHD, because it's cheaper.
As to the popularity of LHD cars in Japan. The idea of having an LHD foreign supercar, or luxury car, is a status symbol in Japan, or at least used to be. This does not mean that having an LHD Fiesta or A160 is a status symbol, just supercars and luxury cars. Based on lurking on the Ferrari Chat forums, that might be changing.