Introducing Zenith G.F.J. Calibre 135 Double Signed with Naoya Hida & Co. - The Beginning Of A Collaborative New Chapter

Photos by Masaharu Wada

It was only last month that Zenith had the watch world talking about its G.F.J. stone dial limited editions when they were released at Watches & Wonders 2026, but today, we have another, arguably even more interesting, follow-up that promises big things in the brand’s future. Enter the Zenith G.F.J. Calibre 135 Double Signed with Naoya Hida & Co., which takes the same historically inspired movement story and brings a touch of classical restraint thanks to Naoya Hida’s young independent watchmaking outfit, Naoya Hida & Co.

For a deeper dive into Zenith’s G.F.J. collection and how it’s evolved over the last few years, make sure to check out the excellent piece by Rich Fordon on the 2025 edition, but as a quick explainer, in 2022, Zenith debuted the Calibre 135 Observatoire that revived one of the brand’s most important precision movements. Produced in collaboration with Phillips and Kari Voutilainen, it was cased in platinum, featured an attractive black dial with a guilloché chapter ring, and was powered by restored, vintage examples of the Calibre 135-O that won Zenith more than 230 Neuchâtel Observatory chronometry prizes during the 1950s.

In 2025, Zenith released the G.F.J. that saw the brand restart production of the Calibre 135 for the first time in more than 60 years, only slightly reengineering the movement to lengthen its power reserve to a more contemporary 72 hours. It too was cased in platinum and featured a blue lapis lazuli dial with a "brick" guilloché pattern around the chapter ring, was limited to 160 pieces, and went on to win the Chronometry Prize at the 2025 GPHG.

The most recent chapter was just over a month ago, when Zenith pulled the covers off two new G.F.J. references in yellow gold with a bloodstone dial and tantalum with a black onyx dial (also both limited editions that were almost all spoken for before the week of Watches & Wonders was finished), and now we have this very different collaboration with Naoya Hida & Co.

If you’ve not come across Hida’s work before, he founded the business alongside two friends - watchmaker Kosuke Fujita and engraver Keisuke Kano - back in 2019 with a vision to create watches that drew inspiration from the golden decades of watchmaking between the 1930s and '60s, while using the very best watchmaking technology available today. Since establishing the brand, Hida and his team have released five series of watches that all feature elements that collectors love today, including modestly proportioned cases, engraved hour markers, and restrained complications.

The collaboration between Zenith and Naoya Hida & Co. brings together much of the best of both watchmakers’ signature styles, arriving with a 39.15mm platinum case that’s kept relatively slender at 10.5mm in thickness, and shaped in the 1950s style that has won Naoya Hida & Co. a legion of collectors around the world. The case is polished to a mirror finish and features an elegant step that wraps around the case from one lug to the other, bringing an extra point of visual dimension to an otherwise quite simple form.

The dial is crafted from solid silver with the main surface finished with a matte, sandblasted texture, while the markers (as well as the Zenith and Naoya Hida & Co. logos) are engraved by Hida’s master engraver and co-founding friend Keisuke Kano before being filled with blue Japanese Urushi lacquer. The hour and minute hands are made from white gold, while the sub-seconds hand is stainless steel that’s been heat blued to nicely pair with the lacquer-filled dial details.

Visible through the sapphire crystal exhibition caseback is the manually wound Calibre 135, which has an oversized variable-inertia balance wheel (complete with a Breguet overcoil), ticking away at 2.5Hz and officially certified by COSC for a maximum accuracy variation of +/-2 seconds a day. As you’d expect, the finishing has been carefully applied, with côtes de genève, hand chamfering, and a dark ruthenium finish that contrasts nicely against the bright warmth of the balance wheel.

The watch comes with no less than three different leather straps, including one made from Himeji Kurozan leather that's received applications of urushi lacquer and hand polishing, another using Wagyu leather, and the third made from deep indigo Japanese non-stretch denim.

Finally, this Zenith G.F.J. Calibre 135 Double Signed with Naoya Hida & Co. marks the first reference released in Zenith’s new The Double Signed Program, where the brand will invite “selected partners to reinterpret a celebrated model”. Double-signed watches have a long history in the world of watches and a growing appreciation among collectors everywhere, so it’s exciting to think about the other independent watchmakers that Zenith could collaborate with in the future, as well as the models that might be included.

With last year’s slightly less limited return of the G.F.J. (compared to the 10-piece Calibre 135 Observatoire of 2022), Zenith clearly knew it was onto a winner, and the success of the two references from Watches & Wonders 2026 further underscores that point. There’s a strong appetite for thoughtfully designed, finely finished time-only watches among collectors at the moment, and Zenith’s G.F.J. collection hits that nail squarely on the head with its use of stone dials, rare and precious case materials, and a movement that could have a history book written about it.

This collaboration with Naoya Hida & Co. refines that approach slightly more, bringing in a totally different design language that’s defined by its attention to detail, proportions, and restraint, perhaps aimed at collectors who already have a stone dial or two in their collection and are yet to dip their toe into the world of independent watchmaking.

While I was personally besotted with the green and red-flecked bloodstone dial of the G.F.J. I saw in Geneva in April, I think this might be my favourite of the bunch so far, partially for its clean, precise dial, but also because of how well it would fly under the radar if you wore it as part of a weekly rotation.

Brand: Zenith
Model: G.F.J. Calibre 135 Double Signed with Naoya Hida & Co.
Reference Number: 40.1865-2.0135/01.C220
Diameter: 39.15mm
Thickness: 10.5mm
Lug-to-Lug: 45.75mm
Case Material: Platinum
Dial Colour: Solid silver dial with all indications hand-engraved and filled with blue Japanese urushi lacquer
Indices: Yes
Crystal: AR-coated sapphire front, sapphire back
Lume: No
Water Resistance: 50 metres
Strap/Bracelet: Himeji Kurozan leather, Wagyu leather crafted in Kyoto, and Japanese non-stretch denim from Kaihara, all with a platinum pin buckle engraved with the G.F.J. initials

Calibre: Calibre 135
Functions: Hours, minutes, seconds
Power Reserve: 72 hours
Winding: Manual
Frequency: 2.5 Hz
Jewels: 22
Chronometer Certified: Yes, COSC

Price: A$103,500
Availability: Sold out
Limited Edition: 10 pieces

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