HGBuild Divers

PFF-X7/E3 Earthree Gundam

A tiny core Gundam that turns into a completely different silhouette in about ninety seconds flat, and does it without a single tool.

MechaGrade Score

3.8/5

Earthree Gundam · 1/144 · 2019

GradeHG

Scale1/144

Released2019

Runnersn/a

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The verdict

This is the best kind of gimmick kit, the transformation actually works and it's genuinely fun to do more than once.

I built the Core Gundam first, ran it through the strip-down into Earthree, and found myself doing the swap again just to watch the Earth Armor lock on. For a first HGBD:R release it nails the one thing it needed to nail.

Best for: builders who want a fidget-toy transformation gimmick and don't mind sacrificing torso articulation for it

The full review

What it is

The kit gives you two things in one box: the small PFF-X7 Core Gundam, based visually on the RX-78-2, and the Earth Armor support mech it docks into to become Earthree. You build both, then follow the manual to strip the armor apart and plug the Core Gundam into it piece by piece. It sounds fiddly on paper and it is a little fussy the first time, but once you know the sequence it becomes a quick, satisfying ritual. I like that Bandai committed to a real docking system rather than a simple color-swap gimmick, this is the same Core Docking idea that lets the suit take other PLANETS System armors sold separately, so the kit is a gateway into a bigger collecting hook.

The catch

The transformation costs you the torso. There's no ab crunch here, the stomach is just two plates on a peg pair, so as Earthree the suit can't twist or bend at the waist the way most modern HG kits can. That's a real downgrade if you're used to newer HGs and want to pose dynamic action shots. It's also a small kit at 1/144 with a correspondingly small kibble, and if you lose one of the Earth Armor's connector pegs during the strip-and-rebuild the docking gimmick stops working cleanly. None of this tanks the kit, but go in knowing the price of that transformation gimmick.

Who it's for

Pick this up if you want a beginner-friendly build with a mechanical trick that actually rewards fiddling, or if the PLANETS System collecting angle appeals to you and you want to start at the beginning with the base Earth Armor. Skip it if torso articulation and dynamic full-body poses matter more to you than the transformation, a straight HG Gundam kit without the core-swap gimmick will pose better. It's also a nice low-stakes pickup for someone newer to the hobby since nub placement is considerate and there's no glue or paint required to get a clean result.

What works

the core docking transformation genuinely works and is fun to repeat, not just a novelty you do once
nub and gate placement is considerate, most connection points sit inside panels or armor seams so cleanup stays clean without color-matching stickers
gateway into the wider PLANETS System, the Core Gundam accepts other armor sets sold separately

Worth knowing

no torso articulation as Earthree, the ab section is a rigid two-piece peg join with zero crunch
small 1/144 scale means the connector pegs for the docking gimmick are easy to misplace or wear loose over repeated transformations
accessory loadout is light, two beam sabers, a shield, and a Core Spray Gun with four effect parts, appropriate for the price but not generous

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The build story

What the build is actually like, and the engineering worth knowing about.

Both the Core Gundam and the Earth Armor go together fast, this is an easy build regardless of experience level. Nub connections are thin and mostly hidden along seams or inside armor plates, so a quick nip and light sanding gets you a clean finish without hunting for color-match stickers. The genuine step is the transformation itself, you strip the Earth Armor's shell pieces off the frame and re-dock the Core Gundam into it following the manual's sequence, and it takes a couple of tries to get smooth.

The standout engineering here is the docking system itself rather than raw articulation. As the compact Core Gundam the suit poses well, closer to what you'd expect from an Iron-Blooded Orphans era HG, but once docked into Earthree that torso rigidity shows up and holds back full-body poses. Where the kit earns its keep is the swap mechanism and the collecting hook it opens, this is the entry point to Hiroto's PLANETS System and other armor sets snap onto the same Core Gundam frame.

Lore & trivia

01The Core Gundam is piloted by Hiroto Kuga in Gundam Build Divers Re:RISE, and its base design visually references the original RX-78-2 Gundam.
02Earthree is the Core Gundam's default blue Earth Armor configuration, the basic all-rounder among the PLANETS System armors named after the eight planets.
03The same Core Gundam frame is compatible with several other separately sold HGBD:R armor sets, including the Marsfour, Veetwo, and Mercuone units, plus the Jupitive Gundam.