mount iwafune is the location where alot of sentai and power ranger battles are fought
Yeah, it's become iconic. In my toku-inspired Tangent Knights audiobook trilogy, I set a huge, important confrontation in Book 3 in a location that was based on Mt. Iwafune and implicitly might have actually been it (or an alternate multiversal counterpart of it). Once I decided to do that, I made sure to have the scene feature a massive explosion.
I recently rewatched Power Rangers SPD and RPM, and I noticed that they used a quarry location somewhere in New Zealand that was a pretty good match for Mt. Iwafune, so they could intercut new and stock footage and it was sometimes hard to tell the difference, except in wider shots.
I wonder when Iwafuneyama started to become a toku location. I haven't spotted its use in shows from the '80s or early '90s, but I recall seeing it in late-'90s Ultraman shows. So I guess it was sometime in the '90s.