In 2025, on the Manufacture’s 160th anniversary, the Calibre 135 was re-engineered to beat at the heart of the new G.F.J. collection, named in honour of the Manufacture’s founder, Georges Favre Jacot. Today, ZENITH introduces the latest interpretation of the G.F.J., co-signed with independent watchmaker Naoya Hida & Co., whose precise and restrained design language brings a singular perspective to the Calibre 135. For Naoya Hida, this was not simply a collaboration, but an encounter with a movement he has studied, pursued, and lived with for decades, approached with a quiet respect for its history and an instinctive sense of what it represents within the tradition of chronometry.
For watch aficionados, double-signed watches from the golden age of watchmaking represent a storied tradition of partnership and are often seen as the ultimate seal of a shared heritage. Today, ZENITH revives this tradition of collaborative masterworks with The Double Signed Program. Born from the belief that iconic design should never stand still, and that excellence grows stronger when shared, this co-creation series invites selected partners to reinterpret a celebrated model. Each collaboration becomes a source of renewal, introducing new sensibilities and references while respecting the essence of the original.
Legacy is not static, it evolves, revealing that when distinct visions meet, beauty gains depth and unexpected energy.
The encounter: ZENITH | Naoya Hida
For this first “Double Signed” creation, ZENITH turned to Naoya Hida & Co. Founded in 2018, the Japanese independent watchmaking brand combines meticulous attention to detail with a deep appreciation for the golden age of mechanical watchmaking. Hida’s watches reflect a deep respect for classical watchmaking, expressed through a rigorous approach to proportion, detail, and precision. The project was born from the encounter between Romain Marietta, Chief Product Officer of ZENITH WATCHES, and Naoya Hida in his Tokyo workshop. Their shared passion for horological history sparked an immediate, intuitive connection, fueled by common references and a mutual pursuit of design excellence and technical perfection.
The collaboration is rooted in a shared ambition: to reinterpret the G.F.J. while contributing to the ongoing legacy of the Calibre 135, a movement Naoya Hida has long revered and pursued.
Presented in an elegant 39mm platinum case, this exclusive 10-piece double- signed limited edition infuses the G.F.J. with the distinctly 1950s-inspired design codes of Naoya Hida’s NH Type 2A. Crafted from solid silver, the dial reflects this precise, restrained design ethos. All indications, including the double ZENITH and Naoya Hida & Co. signature, are meticulously hand-engraved by master engraver Keisuke Kano, before being filled with blue Japanese Urushi lacquer.
The two slender, softly rounded hour and minute hands are milled from solid gold using an ultra-precise CNC machine and hand-polished, while the steel small seconds hand is heat-treated to a deep blue.
Visible through the sapphire case back, the elegant architecture of the hand-wound Calibre 135 is a testament to its history of excellence. It features the decoration introduced on the latest G.F.J. editions, with broad Geneva stripes and delicate hand-chamfering, enhanced by a contemporary dark ruthenium finish accented with yellow gold-coloured markings.
Beating at 2.5Hz, the movement is equipped with a large variable-inertia balance wheel with a Breguet overcoil, as well as Charles Fleck’s characteristic double arrow- shaped regulator for fine adjustment.
This modern re-engineering of the legendary observatory chronometer movement offers an extended 72-hour power reserve and incorporates a stop-second mechanism, while the balance staff is protected by spring-mounted jewel settings. Regulated to +/-2 seconds per day, the Calibre 135 is officially certified by the COSC.
The G.F.J. Calibre 135 Double Signed with Naoya Hida & Co. comes with three distinct straps. The first is crafted from Himeji Kurozan leather, a rare Japanese material celebrated for its rich texture and depth. It combines traditional tanning techniques that reveal the leather’s natural beauty with repeated applications of Japanese urushi lacquer, each layer meticulously applied and hand-polished. The second is made from Wagyu leather, refined using time-honoured techniques by the craftsmen of Kyoto Leather.
The third, in a deep indigo blue, is crafted from Japanese non-stretch denim by the renowned Kaihara Denim mill, reflecting a heritage of artisanal mastery rooted in Fukuyama, Hiroshima. The platinum pin buckle is engraved with the G.F.J. initials.
The G.F.J. Calibre 135 Double Signed with Naoya Hida & Co. is released in a limited edition of 10 pieces.
Benoit de Clerck, CEO of ZENITH WATCHES : “Watchmaking has always evolved through exchange: between cultures, crafts, and passion. With The Double Signed Program, the intention was never simply to reinterpret our Icons, but to create a genuine dialogue between two distinct visions to watchmaking. What I particularly admire in Naoya Hida’s work is his ability to express great depth through restraint. I am grateful for the intelligence and sensitivity he brought to the G.F.J., enriching this timepiece with a perspective that feels both deeply personal and naturally aligned with the spirit of ZENITH.”
Naoya Hida, Founder and CEO of NAOYA HIDA & Co. : “I have been captivated by the Caliber 135 since discovering it in the 1990s. Being offered the opportunity to reinterpret the G.F.J. with ZENITH was both a surprise and a delight. The idea was to capture the atmosphere and spirit of the Calibre 135 era in a modern way. I aimed for something restrained, yet with deep dimensionality… Passion is essential to watchmaking; it cannot exist without it. My greatest joy is being able to create a watch like this—one that truly means something to me.”
Romain Marietta, Chief Product Office of ZENITH WATCHES: “The connection with Naoya Hida was immediate, rooted in a shared passion for the golden age of watchmaking, as well as a mutual curiosity and openness. When different disciplines and sensibilities engage with a classic design, they can bring nuance, tension, and harmony in equal measure—qualities from which true beauty often arises.”
The double signed program
For watch aficionados, double-signed watches represent a storied tradition of partnership, often seen as the ultimate seal of a shared vision. With The Double Signed Program, ZENITH carries this legacy into new hands.
Born from the belief that iconic design should never stand still, and that excellence grows stronger when shared, the project invites a selection of independent watchmakers to reinterpret the G.F.J., a timepiece deeply significant to ZENITH’s watchmaking legacy. Each collaboration reveals new details and sensibilities, introducing different perspectives while remaining true to the essence of the original.
The Double Signed Program extends the life of these timepieces, guided by a shared passion and understanding of watchmaking, evident to those who know.
