Afterword
Osamu Tezuka noted that, after his breakthrough manga Shin Takarajima ("New Treasure Island") was released in 1947, Kansai was deluged by Osaka-made Akahon manga ("red book", due to the red ink used on the covers). Various publishing companies wanted to break away from the junk comic books and start releasing "real" books, so Tezuka proposed creating an epic, full-length science-fiction graphic novel.
Having only half a year to create a 160-page story, Tezuka assembled a basic plot from elements of unpublished work, the inspiration for the central character coming from a publicity still of the female robot from Metropolis (even though he had never seen the film or even known what it was about). When the manga was released, the response from the public was far greater than he imagined and that many students were inspired to become manga artists because of it.
The setting was based on pre-war Manhattan and Chicago, Emmy and her sister partly from Les Misérables, Michi's powers from Superman (perhaps, although Tezuka never made the connection between the title of his work and Superman's city), Michi's burning from The Invisible Ray, and Michi's death scene from The Monstrous Fellows of the Country Underground (another Tezuka manga from 1948).
The characters Duke Red and Notarlin made their debut in Metropolis, and both of them featured in later works. The character of Michi became the prototype for both the lead characters of Astro Boy and Princess Knight, neither of which may have come into existence without him/her (Michi even made a cameo as Hoshie Tenma, Astro Boy's mother).
Read more about this topic: Metropolis (manga)