Hachigatsu wrote:
Specifically, what? Grocery list, please.
Both STAR WARS and MESSAGE FROM SPACE have:

1.Scuffed up, non-streamlined off-white spaceships doing WWII dogfights (previous Toku spaceships were sleek and colorful, like "rockets/flying subs vs saucers".)
2.Villains flying around in planet-sized fortresses that can blow up whole planets with 1 shot. (MESSAGE's "deathstar" owed more to SPACE 1999, though.).
3. Said superfortress having 1 hard to reach vulnerable spot where 1 missile can destroy the whole thing. Heroes fly their space jets into a tight space to do just that.
4. Heroes guided/aided by mystical supernatural force rather than technology.
5. Comical emotional robots. Before STAR WARS, most movie robots didn't display much emotion.
6. Some music themes sound very similar to cues from STAR WARS.
7. Swordfights in a futuristic setting.
8. Beam weapons that shoot like machine guns.

I never accused MESSAGE FROM SPACE of being a ripoff of STAR WARS, but I think the success of George Lucas' movie was a big factor in its getting made and released. But I somehow suspect that the original script bore less of a resemblance to STAR WARS than what we eventually saw, and was revised because the Toei execs wanted something that was a sure thing at the box office. A lot of space sci-fi scripts got dusted off in the wake of STAR WARS, and certain marketable elements of that film were probably pencilled in.
STAR WARS itself was simply Buck Rogers/Flash Gordon with 2001- A SPACE ODYSSEY effects along with some other more obscure references thrown in. But it made a lot of money, thus inspiring movies like MESSAGE FROM SPACE and STAR CRASH, as well as revivals of the serials that in turn inspired it (BUCK ROGERS and FLASH GORDON).