There are movements created simply to power a watch and movements that ultimately define an entire era. The Calibre 135 belongs to this second category. Following its contemporary rebirth and the launch of the G.F.J. collection, ZENITHnow presents the new ZENITH G.F.J. Calibre 135 Double Signed with Naoya Hida & Co., the first chapter of the new The Double Signed Program.
Crafted in an elegant 39.15 mm platinum case, produced in just 10 pieces and powered by the modern reinterpretation of the famous Calibre 135, now COSC-certified, the new model represents the meeting point between Swiss watchmaking culture and the rigorous aesthetic philosophy of independent Japanese watchmaker Naoya Hida.
While maintaining the classic G.F.J. layout, with hours, minutes and small seconds at 6 o’clock, this new interpretation introduces a completely different reading of the project through a hand-engraved solid silver dial and details executed with blue Japanese Urushi lacquer, blending two deeply different yet surprisingly complementary watchmaking cultures.
THE RETURN OF THE CALIBRE 135 BEGAN IN 2022
Although today the Calibre 135 has firmly returned within the ZENITH universe, its modern rebirth did not begin with the G.F.J. The first true reappearance of this historic movement came in 2022 with the ZENITH × Phillips × Kari Voutilainen Observatoire Cal.135-O, a collaboration that many enthusiasts consider one of the most interesting projects of recent years and which we explored in detail in our dedicated article about the ZENITH × Phillips × Kari Voutilainen Observatoire Cal.135-O.
The idea was born from the desire to recover 10 authentic Calibre 135-O movements produced between 1950 and 1954, namely the version specifically developed for observatory chronometry competitions. Restored, decorated and hand-finished by Kari Voutilainen, these movements gave life to an ultra-exclusive series that brought one of the most important calibres in watchmaking history back into the spotlight for the first time.
More than a simple reissue, that project represented a bridge between past and present, demonstrating how a movement created exclusively in pursuit of precision could still speak to contemporary enthusiasts.
WHY THE CALIBRE 135 IS SO IMPORTANT
Originally developed in 1949, the Calibre 135 was designed with an extremely precise objective: achieving the best possible chronometric performance in observatory competitions.
In its 135-O configuration, prepared by chronometrists Charles Fleck and René Gygax, the movement won five consecutive first prizes in the chronometry competitions of the Neuchâtel Observatory between 1950 and 1954, an achievement that still represents one of the most important chapters in the history of mechanical chronometry.
Even today, many enthusiasts consider the Calibre 135 one of the finest manual-winding movements ever produced by ZENITH, not only for the results it achieved but also for the unique architecture developed exclusively in the name of precision.
FROM THE CELEBRATORY G.F.J. TO AN EVER-EVOLVING COLLECTION
The transformation of the Calibre 135 into a contemporary collection arrived in 2025, the year of ZENITH’s 160th anniversary, with the debut of the G.F.J., whose name references the initials of founder Georges Favre-Jacot. At the time of its presentation, we analysed in detail the ZENITH G.F.J. Platinum Calibre 135, the celebratory model that marked the contemporary return of the legendary movement.
At Watches and Wonders 2026, ZENITH further expanded the G.F.J. universe, proving that the project represented the beginning of a true collection rather than an isolated episode. The Maison introduced two new interpretations.
The versions presented at Watches and Wonders 2026 explored different materials and aesthetic languages. This new interpretation, however, introduces something different: not a simple variation of dial or case, but a genuine creative dialogue.
The first, limited to 161 pieces, combines an 18-carat yellow gold case with a dial featuring a central Bloodstone disc, a natural stone characterised by green shades and red inclusions that make every piece unique.
The second, produced in only 20 pieces, instead uses a tantalum case, a rare material known for its density, machining complexity and distinctive bluish-grey tone, paired with a black onyx dial and baguette-cut diamond indexes, offering a decidedly more contemporary interpretation of the original project.
THE DOUBLE SIGNED PROGRAM IS BORN
For enthusiasts, double signed watches represent one of the most fascinating chapters of collecting and contemporary Haute Horlogerie. Historically, double signatures identified special collaborations between manufactures and selected partners, gradually becoming extremely sought-after objects.
With The Double Signed Program, ZENITH chooses to bring this tradition into the present through a series of collaborations with independent watchmakers invited to reinterpret some of the Maison’s most symbolic models while preserving their essence intact.
As explained by Benoit de Clerck, CEO of ZENITH WATCHES: “Watchmaking has always evolved through exchange: between cultures, crafts and passions. With The Double Signed Program, the intention was not simply to reinterpret our icons, but to create an authentic dialogue between two different visions of watchmaking.”
THE MEETING BETWEEN ZENITH AND NAOYA HIDA
To inaugurate this new journey, ZENITH selected Naoya Hida & Co., the independent Japanese brand founded in 2018 and renowned for its rigorous approach to proportions and classical watchmaking.
The aesthetic inspiration comes from the NH Type 2A, one of the most recognisable models in Naoya Hida’s production. The dial does not simply adopt Japanese stylistic codes but becomes a true artisanal expression. All indications, including the ZENITH and Naoya Hida & Co. signatures, are hand-engraved by master engraver Keisuke Kano and subsequently filled with blue Japanese Urushi lacquer, a traditional technique requiring multiple applications and extremely delicate polishing.
The slender hour and minute hands, characterised by a soft and slightly rounded profile, are crafted from solid gold, machined using high-precision CNC technology and polished by hand, while the small seconds hand undergoes a thermal treatment to achieve its characteristic deep blue tone.
For Naoya Hida, this project carries deeply personal meaning: “I have been fascinated by the Calibre 135 ever since I discovered it in the 1990s. The idea was to capture the atmosphere and spirit of the Calibre 135 era through a modern lens. I wanted something essential, but with strong depth.”
EVEN THE STRAPS TELL THE STORY OF JAPAN
Naoya Hida’s influence also continues in the choice of straps. The watch is delivered with three different options: Himeji Kurozan leather, a rare Japanese material treated through successive applications of Urushi lacquer, each applied and polished by hand, Kyoto-crafted Wagyu leather and indigo-coloured Kaihara Japanese denim, originating from the artisanal tradition of Fukuyama, Hiroshima.
Completing everything is a platinum pin buckle engraved with the G.F.J. initials.
THE CALIBRE 135 CONTINUES TO LOOK TOWARDS THE FUTURE
Visible through the sapphire crystal caseback, the manual-winding Calibre 135 retains its historical architecture while being reinterpreted through broad Côtes de Genève, hand-executed anglage, a modern dark ruthenium finish and yellow gold-coloured details.
The movement also preserves the historic frequency of 18,000 vibrations per hour (2.5 Hz), a choice that maintains the original character of the Calibre 135 while integrating contemporary elements such as a 72-hour power reserve, hacking seconds, Breguet hairspring, the famous Charles Fleck double-arrow regulator and jewel settings mounted on springs to protect the balance staff.
Regulated within ±2 seconds per day and officially COSC-certified, the movement reaffirms that pursuit of chronometric precision which for more than seventy years has represented the soul of the Calibre 135.
PRICE AND AVAILABILITY OF THE ZENITH G.F.J. CALIBRE 135 DOUBLE SIGNED
Produced in just 10 pieces, the new ZENITH G.F.J. Calibre 135 Double Signed with Naoya Hida & Co. will be available at a price of CHF 58,900.
More than a simple limited edition, it feels like the meeting point between two different ways of understanding watchmaking: on one side the Swiss tradition of chronometric precision, on the other Japanese minimalism built around proportions, details and subtraction. The result does not shout, does not seek special effects and that is probably its greatest strength: succeeding in giving a new voice to a legend without distorting its character.
By Jacopo Giudici