I first found out it was originally a Japanese show when I browsed a local comic shop back at home around the time the original MMPR came out. They had a video rental section where you could rent all sorts of Asian flicks, from Kung-Fu Theater stuff to anime. It was there that I stumbled onto a video casing of what I thought was the Power Rangers, then the store clerks proceeded to explain to me what the original Super Sentai series was all about. At the time, I was kind of confused about it, but I did get the general idea that "Yeah, PR originally came from Japan, and it's more brutal than what Saban would show over here." Of course, back in those days, I thought Tommy doing the Hadouken on the other five was the worst thing I've ever seen in my life (now I think it's the most awesomest thing EVAR). When I heard "The Green Ranger dies in the original", I was like :O_O:.
Of course, a few years later, as Dino Thunder airs, I stumble upon Super Sentai.com, where it would go more in-depth with the series.