I like this thread, because it celebrates one of the unsung artistans of the classic era of Toho's kaiju fantasy genre, "mr. Pyrotechnics" himself, Teruyoshi Nakano. This guy was a true champ for having to work through the most difficult times of the Japanese film industry. His effects work may appear a bit shoddy at times, but as it has been reiterated many times already in this thread, the blame cannot really be placed solely at his feet.
So, I guess the question being posed here, really, is "which seventies Godzilla movie contains Teruyoshi Nakano's best special effects work"? In my opinion, it all comes down to a two-way tie: Godzilla On Monster Island and Terror of Mechagodzilla. i know what you're probably thinking, "But Godzilla vs. Gigan is half stock-footage!" This is true, but still, the main idea behind that whole production was to make it look as much like a "traditional Godzilla movie" as possible, and I honestly believe that, despite the over-abundance of stock-footage, the artificial darkening of some scenes, and some rough-looking models and prop-work, Nakano really does some of his best work here. The arrival of Godzilla, and the following battle at the oil refinery is expertly photographed, well-lit and overall beautifully staged. Nakano plays to his strength, which is basically blowing alot of stuff up, and he goes all out, with King Ghidorah simply lighting up the entire dock section of Tokyo with his lightning breath. It is definitely a high-light of the series. Overall, I think that Godzilla On Monster Island contains effects work with alot of guts and dedication in the face of Toho's crippling budget constraints. Nakano even said himself in and interview back in '97 "I tried my best", and the way he spoke of his work on this movie bears this out. Or perhaps, I love this movie so much, I just wanted to give it some extra love by pumping up the credibility of the guy who created some of my all-time favorite kaiju fight scenes! Seriously, Teruyoshi Nakano is The Man!! I just watched the original version of Godzilla 1985 and I thought to myself "yeah, Nakano was really giving it his all on this one!" Do you agree?
Anyway, yeah, my vote goes for Terror of Mechagodzilla however, with Godzilla On Monster Island getting a very honorable mention. I think that having Ishiro Honda at the helm really inspired Nakano to embrace a wider scope, and get out of the oil refineries and mountainous terrains of the previous four Godzilla movies. In Terror, you get to see Mechagodzilla literally level an entire city, and Nakano really blows that muther****** up! Sure, there are some painfully awful moments here and there, but I think that was merely a result of Nakano challenging himself to create more different kinds of effects than he was previously used to. I truly believe that Terror of Mechagodzilla was a learning experience for the man, because the overall look of his work here is pretty damn-good.
"EVERYONE FORGET YOUR TROUBLES! ENJOY YOURSELVES!THERE'S NOTHING TO WORRY ABOUT!" - Gigantis The Fire Monster
"It was HUGE...It was...IT WAS LIKE A MONSTER!!! Suddenly the rocks rose...ALIVE!" - Godzilla 1985