The gothic fashion and subculture started in the 1980s and 1990s, I think so I hope this doesn't violate the 20-year old rule.
Seriously? How did "Gothic" subculture and fashion or the "Goths" get their name? They're not probably named after the Visigoths and the Ostrogoths who invaded the Western Roman Empire, hence called the "Goths" or are they?
Do you have a citation for Gothic fashion being Japanese American? Or even just a casual source?
I don't think I've ever heard of being attributed to Japan or America, originally. It was in Britain before it was popular in America. That might be a good place to start.