US Equiuvalent: Prime
Japan's release of Transformers: Prime was a localization of Hasbro's CGI animated series and corresponding toyline. Since Hasbro's media led the way in terms of design aesthetics and storyline, the Japanese toy releases lagged behind the Western ones, allowing them to develop and implement a very different play pattern from the US Prime line. Japan also eschewed the entire Beast Hunters portion of the Prime toyline as well as the corresponding third season of the show, choosing instead to adapt the Beast Hunters themed toys into Triple Combination: Transformers Go! and Adventure → alongside new designs (in Go!) and ports of Robots In Disguise toys (in Adventure).
Without Beast Hunters, Japanese TF: Prime was broken into three main subtitles. Like the Hasbro release, the line started out as First Edition, with packaging closely matching the style of the US releases , including the cardboard display bases included in the packaging beneath the figures' feet, and lacking the ID numbers typical of Japanese-market Transformers. The toys themselves differed only in plastic colors, with most being a much darker, richer metallic base plastic than the corresponding US release. The Deluxe-Class Megatron figure from the US Rivalry Reborn versus pack was also available as a carded regular figure, unchanged from that previous release.As the US line transitioned to the mass-release "Robots In Disguise" subline, the TakaraTomy designers unveiled their wildly different take: Arms Micron. Capitalizing simultaneously on the popularity of Microns (known in the West as Mini-Cons, from Armada onward) and model-building and customizing, the Arms Micron subline featured Deluxe and Voyager Class toys boxed with sticker sheets in place of factory paint and tampograph details, and Micron model kits on a runner or sprue for the user to build and transform. The sticker sheets were applicable to both the main figure and the Micron, and many included optional stickers to further customize the toy, as well as the stickers necessary to replicate the on-screen appearance of the character. The boxes and product catalogs further featured various "Combo Weapons" constructed out of Microns from different sets, as well as "Arms Up Modes" depicting the main figure adorned with various Combo Weapons and other Microns. Given that all of the figures and Microns had added 5mm posts and holes, there is massive interchangeability to promote a creative, almost LEGO-like play style. TakaraTomy also released single and multi-packed Arms Microns, both in unique designs and in redecos of those packaged with main figures. The Autobot Microns are almost entirely themed as bipedal robots with cute proportions and faces with two eyes and mouthplates, while the Decepticon Microns almost all feature a beast mode with a sinister red (once the label is applied) mono-eye.
The Arms Micron portion of the toyline is often notable to Western fans for its inclusion of several TV-show characters not released outside Japan, such as Breakdown (as War Breakdown), Unicron (as Gaia Unicron), Nemesis Prime, and Smokescreen (who would eventually see a much more screen-accurate release in the West in Beast Hutners). This led to fans importing large numbers of these unique toys (and in some cases, high aftermarket values), despite relatively low interest and importation of the characters available on US shelves.
The third portion of Japan' Prime line was an extension of EZ Collection, which had been introduced as a cross-line brand to include Legends Class and Cyberverse toys. The Prime portion of EZ Collection was almost identical to the US lineup. The only unique sets were the "Autobot Set" and "Decepticon Set", two five-piece gift sets featuring redecoes of Cyberverse Legion and Commander figures in richer, sparkly colors, and a Cliffjumper toy in translucent purple to represent his Terrorcon form.
Despite being so specifically tailored to Japanese consumer tastes, Prime Arms Micron has had some measurable impact on Western Transformers aside from high-priced War Breakdowns on the collector market. Many of the Microns have appeared in Transformers Club Figure Subscription Service and BotCon exclusive sets. Fans who enjoy collecting Mini-Cons often seek out the numerous Microns, though this sometimes leaves incomplete main figures languishing in the aftermarket.