Japan was not the first country to pursue industrial robotics, but it did so with uncommon enthusiasm, an attitude which remains to this day: As of 2008, the country still leads the world in both stock and sales of industrial robots. As robots took their place in Japanese factories, so too did they take their place in Japanese pop culture. In 1952, Osamu Tezuka, now considered one of the forefathers of modern manga, published the first volume of Tetsuwan Atomu, known in the West as Astro Boy. Astro Boy followed the eponymous young robot as he fought crime and discovered humanity in a classic Pinocchio tale. Unlike most Western robots, such as those of Isaac Asimov or The Jetsons' Rosie, Astro Boy was not a servant or a sidekick; in his story, the robot was the hero.
Things only got bigger from there. Astro Boy was followed by Tetsujin 28-go (or Gigantor in the West) in 1956, which many consider the forerunner of modern mecha - a term which has come to refer to advanced machines and vehicles that walk, are controlled by a pilot and are usually human-shaped. Go Nagai's Mazinger Z, first published in 1972, was the first to feature the now-standard idea of a pilot controlling the giant machine from a cockpit inside its body. All of these early mecha series were incredibly influential, and all retain some measure of popularity even today - Tetsujin is even getting its own life-size statue in Kobe, for example.
But somehow, Gundam still towers over every other mecha series. After all, where are the inventors announcing plans to build a full-size, working Tetsujin within 10 years? Where is the exasperated announcement that Japan's Agriculture Ministry "is not in charge of Astro Boy"? Why does a country that loves robots so much love Gundam more than the rest?
Flight Toward the Future
Gundam may not have been the first giant robot series, but it did pioneer the so-called "real robot" genre. Whereas "super robots" like Mazinger or Tetsujin are usually magical heroes whose enemies are generically-evil "foreign agents" like monsters or aliens, and whose pilots win the fight based on their courage and fighting spirit, the "real robot" genre is less fantastical and grounded more in human concerns.
The antagonists of Gundam weren't monsters, but merely other humans who lived in space colonies around the Earth. The titular RX-78-2 Gundam (and all of the franchise's machines that would follow in its footsteps) was no magical being, but rather a powerful piece of military hardware, and main character Amuro Ray was an engineering student who fell into the cockpit and controlled it after reading the owner's manual. It was a show filled with shades of gray, where the protagonists could be cowards and the antagonists could be soldiers simply doing their duty and where characters on both sides of the universe's One-Year War - or those caught in the middle - could perish without warning. (Indeed, as befits a country whose constitution forbids it from possessing a standing army, the various shows in the Gundam metaseries are all rather anti-war in some regard.)