While I grew up with Ultraman, I've not really seen any Kamen Rider, other than random episodes here & there. So for me, as always, I'd want to start at the beginning. But if kamen Rider Series (like Ultraman & Godzilla) are broken up into era's, I'd have no clue where one ends, and the next begins.
I know Ultraman 80 was technically the last Showa live action series (Since the TPC/Hanna-Barbera animated film came out in 88 I guess it would be the first Heisei era entry??)
But since Godzilla and Ultraman had nearly a decade lapse in each of their franchises, is easy to distinguish. Did Kamen Rider have a similar gap in the 80's?