Writing Special effects director Sadamasa Arikawa noted that Toho were going to potentially end the
Godzilla series as "Producer Tanaka figured that all the ideas had just run out." Several sources attest that the film was announced alongside
Son of Godzilla, possibly as a competing project. The film was written by
Takeshi Kimura and
Ishirō Honda, making it the first
Godzilla film since
Godzilla Raids Again not written by
Shinichi Sekizawa. Takeshi Kimura is credited by his pen name Kaoru Mabuchi in the film's credits. Kimura and Honda's script developed the concept of Monsterland (referred to as Monster Island in future films). The earliest screenplay, written by Kimura in 1967, was titled
Monster Chushingura (怪獣忠臣蔵, Kaiju Chūshingura). (The word
chushingura refers to a famous historical story in Japan about the
rebellion of 47 samurai who took revenge after their master was unjustly forced to commit suicide). Supposedly, in this version, every monster in Toho's arsenal was to be included, even
King Kong and Sanda and Gaira from
The War of the Gargantuas. In an interview with David Miller, Ishiro Honda even said “the original idea was to show all of the monsters.” The first initial screenplay, preliminary titled
Monster Total Advancement Order (怪獣総進撃命令, Kaijū Sōshingeki Meirei), by Takashi Kamura (as Kaoru Mabuchi) was submitted on November 22, 1967, and included a confirmed roster of Godzilla, Mothra (larva), King Ghidorah, Rodan, Baragon, Varan, Kumonga, Manda,
Maguma, and Ebirah. Everything plays out just as in the finished film except that Maguma and Baragon guard the Kilaak base and Baragon actually attacks Paris. Also, in this iteration, Varan and Rodan work in tandem to attack Ghidorah in the final battle. When it was decided to adapt
Two Godzillas!: Japan SOS (an earlier version of
Son of Godzilla) instead, the script was shelved for next year. By then the rights to Kong had expired. Honda also wanted to show lunar colonies and brand new hybrid monsters, the results of interbreeding and genetic splicing. He planned to delve more deeply into undersea farming to feed the monsters, but because of budget constraints this was not included. In later scripts, the number of monsters was cut as well.
Filming Director Honda was fascinated by the concept of a "monster farm", in particular the idea of how humanity could feed them. He noted that a "huge amount of protein" would be needed and envisioned cloning along with undersea farming to accomplish this. However, despite the director's fascination with this concept, the final movie devotes very little time to it outside of the brief introduction to Monsterland and showing Rodan feasting on a dolphin. The director laments that of the original complex idea only the basic "idea of [a] Monster Island survived." As the film has several monsters who continuously return in the films, the location was developed to be a faraway island where the monsters are pacified. This tied other films not related to the
Godzilla series within its universe, as creatures such as
Manda (from
Atragon) and
Varan (
Varan the Unbelievable) exist. The film features footage from
Ghidorah, the Three-Headed Monster (1964), specifically
King Ghidorah's fiery birth scene. As with
Ebirah, Horror of the Deep, Teisho Arikawa was the actual special effects director for the movie, although Eiji Tsuburaya is credited for it. Tsuburaya had more of a supervisor role regarding the special effects. During the monster's attack on Tokyo, you can see Godzilla steps over a construction crane model. Looking back on it, Haruo Nakajima did so because he worried he might trip over it and fall. He regretted doing that since he should have kicked it out of the way since it was a very non-monster like thing to do. During the movie's production, Toho arranged for a visit to the Mount Fuji set by a group of around 100 kids who were entering first grade, who got to see all the monsters in action, as well as actors Akira Kubo and Jun Tazaki. Actress Yukiko Kobayashi, as well as the monsters, also paid a visit to a member of the child actors cast of an Imperial Theater of London production of
Oliver! in Tokyo. At the climactic battle at Mount Fuji, Haruo Nakajima wanted Godzilla to reprise his “jumping shie” from
Invasion of Astro-Monster, but Ishiro Honda removed it from the final film.
Special effects New monster suits for Godzilla and
Anguirus were constructed for the film, while
Rodan, Kumonga, Minilla, Gorosaurus, Manda, Baragon, Mothra, and King Ghidorah suits were modified from previous films, with Ghidorah having less detail than he had in previous films. There were 3 different scales of the Moonlight SY-3 created or the film. The largest was 1 meter (3 feet) long used mainly used for shots of the spaceship flying across the surface of the Moon, landing and taking off, and for battle with the Fire Dragon (UFO). The core of the model was solid wood with surface details made of balsa wood and molded fiber glass with putty and paint used to disguise the wood grain and the seams. This model had collapsible wings, functional landing gear and fully firing engines. A 50 cm version was made for use for the booster stage and a 30 cm version was made for perspective flying shots. Both smaller versions were made of balsa wood covered in putty and paint. For the scene when Gorosaurus comes out of the ground (through a tunnel presumably dug by Baragon) under the
Arc de Triomphe, the floor of the set was six and half feet above the ground with the arc built on top of it. A forklift was brought in under the set and the monster was put on the forklift. They then raised the monster up through the ground by raising the forklift. The fire trap set by the Kilaaks to trap the Moonlight SY-3 used real flamethrowers. Fire retardant materials were used in the rock walls in the crater.
Deleted scene After attacking New York, Godzilla was to arrive in London and fight Manda but the scene was cut. The scene was included in the 1990s bonus features of the film's Japanese LaserDisc. Director Ishirô Honda said about it, "Why was the scene is cut? Because it doesn't makes sense storywise. Godzilla and Manda were being mind-controlled by the same villains, they wouldn’t just start fighting each other. " ==Release==