Happy 40th Anniversary to the original Daicon 4 Film! It was first screened at Daicon IV opening ceremonies in Japan on August 20th, 1983. Hideaki Anno, Hiroyuki Yamaga and Takami Akai would later go on to found Gainax. You can read a translation of the production report from 1983 published in now defunct Animec magazine on Zimmerit here!
On the 20th of August 1983, Daicon IV was released. It was made by Daicon Film, a 12 man studio with the 3 founding members being Hideaki Anno, Hiroyuki Yamaga, and Takami Akai. The studio would later go on to become Gainax studios.