A brief glossary of Japanese terms is necessary to discuss Chogokin:
Chogokin's origins (and indeed all mecha sci-fi) date back to Mitsuteru Yokoyama's 1956 manga Tetsujin 28-go, though the idea of super-robots as a genre exploded in popularity starting with Go Nagai's 1972 Mazinger Z. Bandai subsidiary Popy acquired rights to produce clockwork tin lithograph toys of Chogokin robots like Mazinger Z and Combattler V, often with a small portion of injection-molded plastic to allow the appearance of more detail than the classic box-robots most commonly associated with the tinplate medium. As the price of plastic injection molding and die-cast metal plummeted relative to tinplate stamping, Popy began shifting to production of these robot characters made of these materials branding them as Chogokin. The new production techniques resulted in figures that were slightly smaller, but felt more dense and "sturdy", in addition to having more detail, vacuum-metalized "chrome",and increased articulation. Popy and its competitors used the shift to brand their robots heavily with words related to the die-cast metal alloy ZAMAK, such as Bullmark' "Zincron". Paralleling the rise of die-cast toy vehicles, Popy launched a line called Popinica featuring mostly non-robotic vehicles from the same sci-fi media as the Chogokin robots. Most of the vehicles had some sort of spring-loaded action feature, or even converted between forms. In rare cases, the vehicles were actually the alternate form of a robot that seemed a better fit for the Chogokin line, like Voltes V.
The toys all featured serial numbers, beginning with GA-01 for Mazinger Z, and stretching through nearly 300 numbers from GA- to GB- to GC-, while Popynica' numbering system used PA-, PB-, and PC-. These toylines collected myriad unrelated designs from various shonen TV shows including mecha anime, tokusatsu, and even silly characters designed for the younger end of the demographic. Many of the toys were divided into ST (standard), 5-6 inch figures comprising a more affordable option, and ornate DX (deluxe) versions of the same robots, featuring elaborate construction and numerous accessories, though not all characters were available at both scales. While not part of Chogokin proper, some of the most popular mecha were released in a line called Jumbo Machinder. These nearly two-foot tall robots were made of blow-molded PVC plastic, with limited articulation and some sort of spring-loaded action feature, often firing missiles. Some sets had interchangeable arms, allowing different weapons to be used.
As the late 1970s and 1980s saw a rise in popularity for sci-fi and mecha cartoons and toys in the West, Popy and Bandai marketed some of their more popular models (those requiring little understanding of Japanese shonen culture) to Europe and the Americas. The first such attempt was Shogun Warriors, licensed through US toymaker Mattel, which was supported by a short Marvel Comics series. A storm of controversy erupted over the safety of the toys in the US's highly litigious society, due to the small spring-fired projectiles supposedly posing a choking hazard to children. A few years later, Bandai America imported the toys directly (reportedly lacking only the English-language outer boxes and instructions, which were added at a US warehouse) as GoDaiKin, a reshuffling of "gokin" (alloy) and "dai" (big). While impressive to US buyers, these toys were very expensive, and the lack of advertising in their own cartoons or other media left them to languish in the shadow of the numerous sensational toy/cartoon series at the time.
Several other Japanese toymakers joined the craze, most notably Clover and Takatoku, who partnered with different anime and manga studios to produce robot toys of similar construction and configuration. By the mid-80s, Bandai's dominance in the market left their competitors in bankruptcy, and Bandai purchased much of the intellectual property. In the late 1990s, as the toy collecting hobby surged in popularity among former children of the '70s and '80s, Bandai started Soul of Chogokin, modern re-imaginings of their most famous mecha in elaborate detail for adult collectors. Soul of Chogokin eventually expanded to include super robots acquired from Popy, Clover, and even contemporary competitor Takara (now TakaraTomy). The high-quality and painstakingly-detailed Soul of Chogokin toys became so desirable to collectors that their prices sometimes rival that of the original toys, despite the relative rarity of originals in good condition.
The Chogokin line firmly cemented robots as viable centerpieces to boys' entertainment, which would lead to the branching off of another major genre: Real Robot, which places the mecha in a less magical setting as a natural evolution of military equipment, or even as sentient beings disguised as objects in the contemporary world.