[Matrixbeast]

Moon Knight was created in '75, making it really unlikely in an era where media from one country was a lot more difficult to even make it to another without a full publishing.
There was a Moonlight Mask anime in '72, but I still hold my doubts simply because: Who at Marvel would have access to it?
(Marvel's deal with Toei started in '78, so I doubt Toei would be throwing them untranslated VHS's of random anime and Toku during '75 to influence Moon Knight).

[TimeCrimson]

Chouseishin series definitely. I've enough parts from all three to say that they are all awesome, and have awesome stunts and choreography, with a mech dynamic that isn't much repetitive like Sentai. And all have their fair share of drama and comedy, making a blend. I wish it got more recognition, because I adore the heck out of this series, and sometimes it's on par with Sentai in my opinion.

Tomica Hero also is really good, I love Rescue Force but haven't seen Rescue Fire, but that's an awesome one too.

[Guyver Spawn]

For other giant superheros there is Ambassador Magma (Based on a manga from Osamu Tezuka) and Specter Man. Ambassador Magma air almost a week before Ultraman did.

[GreenPsychoRanger]

Specter Man looks like a cross between Ultraman and Planet of The Apes.

[Guyver Spawn]

Specter Man is cheesy and dated, but it's still enjoyable if you are into Ultraman.

[Idol Thoughts]

Definitely DaiMajin Kanon. Full of heart.

If you wanna get a little Shōwa, Kaiketsu Zubat and Iron King. I haven't finished either, though I'm close to finishing the latter. Both are great fun.

[Guyver Spawn]

There's Golden Bat. Japan's first superhero and had two movies. One in 1950 and one in 1966.