Generation One, originally known simply as “The Transformers” is the first series of Transformers. In the U.S., the toyline ran from 1984-1990; in Europe, from 1985-1993 (excepting the U.K. which saw limited 1984 releases), and in Japan from 1985-1992 (with many variations from the other regions.)
The line is by far the most diverse in terms of toy styling and design. The early years, 1984-1985, focused on toys originally manufactured in different colors for other brands, such as Takara's Diaclone and Microchange, Bandai's Macross and Takatoku's Dorvack and Beetras. These toys had differing design ethics, but most transformed into recognizable real-world vehicles, and had limited articulation in robot mode.
During this time, many competing brands of shape shifting robots were on the market, so Hasbro designed the “rubsign” as a mark of authenticity. These black and silver square stickers featured prominently on the toy, and would change colors when heated to reveal the allegiance of the character.
In 1986, the success of Transformers justified investment in new and unique designs. Many of these followed in the tracks of their predecessors, including use of some unproduced designs penned for previous toylines. The main theme shifted to Transformers that could combine in teams to form larger robots. It was not a new concept, but accounted for nearly half of the releases that year.
Following the animated movie in 1986, the original story thread frayed and lost its hold over toy design. Subsequent years featured more and more robots with fictitious or sci-fi alternate modes, and toys focused in groups on specific gimmicks. Many of these gimmicks involved a smaller “partner” who could become the head, weapon, or engine of the larger figure. Some robots could be disguised as monsters or humans by hiding in a hollow “shell”. However, every year presented more combining teams.
As sales in the U.S. began to slow in the late ‘80s, Transformers downsized in an attempt to offer toys at a lower price-point, and capitalize on the popular “micro” toy concept. Some of these smaller robots, the “Micromasters” were sold in teams of four or six simple, tiny figures. Larger toys simply came with a base or playset. Previous “subgroups” also saw new designs that shrunk and simplified their concepts.
As the line came to a close, the final subgroup threw the old ethic to the wind: Action Masters. Popular characters from early in the series were rendered as non-transforming action figures, including weapons or vehicles that could transform. At the end of 1990, the series was cancelled in the United States due to tanking sales. Japan would see new designs for a further two years, and Europe for another three.
Generation 1's legacy would rule the Transformers into a new millennium, having established the universe, the concepts, and the main characters that are still most memorable today.