This model is part of ZENITH's "Double Signed" initiative. This series reinterprets iconic models with select independent watchmakers, aiming to infuse them with new sensibility while preserving their original essence.

 

It is an endeavor to carry forward the tradition of partnership embodied by double-signed watches from the golden age of watchmaking into the present day.

 

Caliber 135 holds a special place in ZENITH's legacy. It is widely recognized as a symbol of exceptional craftsmanship, having garnered numerous accolades during the golden era of observatory chronometer competitions.

 

In 2022, ZENITH revived this movement. Master watchmaker Kari Voutilainen meticulously recreated 10 units of the Caliber 135-O, based on the 1950s observatory competition specifications, releasing an exceptionally rare limited edition. Furthermore, in 2025, to commemorate its 160th anniversary, the Caliber 135 was redesigned and reborn as the new "G.F.J." collection, named after its founder, Georges Favre-Jacot.

 

The chosen partner for the "Double Signed" initiative is Naoya Hida of NAOYA HIDA & Co. Founded in 2018, the brand is renowned for its meticulous attention to detail and deep understanding of the golden age of mechanical watchmaking.

 

 

This collaboration reportedly began when Romain Marietta, ZENITH's Chief Product Officer, met Mr. Hida at his Tokyo atelier. A shared passion for watchmaking history, coupled with a pursuit of exceptional design and flawless execution, forged their connection.

 

For Mr. Hida, this reunion with Caliber 135, a movement that has captivated him since the 1990s, transformed the project into more than just a commercial collaboration; it became an opportunity to redefine the value of a timepiece.

 

 

The case of this timepiece measures 39mm and is crafted from platinum. The solid silver dial features all inscriptions, including the double signature of ZENITH and NAOYA HIDA & Co., engraved using a micro-engraving machine.

 

The three Arabic numerals are hand-engraved by master engraver Keisuke Kano. The engravings are then meticulously finished with Japanese lacquer, creating a striking blue hue.

 

The slender hour and minute hands are milled from solid gold using a high-precision CNC machine and then hand-polished by a team led by watchmaker Kosuke Fujita. The steel small seconds subdial is treated with heat to achieve a deep blue finish.

 

 

Visible through the sapphire crystal case back, the Caliber 135 has been modernized to ensure durability for daily wear. Its power reserve has been extended to approximately 72 hours, and a hacking mechanism has been incorporated. It features a large variable-inertia balance with a Breguet hairspring and the distinctive double-arrow regulating organ designed by Charles Fleck, oscillating at 2.5Hz for exceptional accuracy within ±2 seconds per day.

 

The movement's decoration also follows the aesthetic of the latest "G.F.J." edition. Broad Côtes de Genève stripes and delicate hand-chamfering are applied alongside a dark rhodium finish and yellow gold-colored engravings.

 

Three distinct straps are included. The first is crafted from Himeji Kurozangoku, a leather treated with traditional tanning techniques and lacquer, meticulously layered and hand-polished. The second is a domestic cowhide strap finished using traditional techniques by Kyoto leather artisans. The third is made from "Kaihara Denim," a non-stretch Japanese denim produced by Kaihara, based in Fukuyama, Hiroshima Prefecture, notable for its deep indigo blue. The platinum pin buckle is engraved with "G.F.J."

 

 

Regarding this collaboration, ZENITH CEO Benoit de Clerck commented:

 

"Double Signed" is an invitation to dialogue, participation, and creative exchange—a project that generates fresh interpretations while honoring the original. It imbues familiar collections with new meaning, revealing beauty not only in continuity but also in difference. I am grateful to Naoya Hida for bringing his understated yet refined design sensibility to the "G.F.J." His keen sense for balance and depth respects the heritage while forging new territory for the "G.F.J."

 

Naoya Hida, founder and CEO of NAOYA HIDA & Co., added, "Ever since I encountered Caliber 135 in the 1990s, I have been captivated by this movement. The opportunity to reinterpret ZENITH and the "G.F.J." was both a surprise and a joy. This piece began with the concept of expressing the atmosphere and spirit of the era in which Caliber 135 was born, using contemporary methods. I wanted to create something that was understated yet possessed profound charm. Passion is indispensable in watchmaking; it simply cannot exist without it. This watch holds deep significance for me, and the ability to create such a timepiece is, above all else, a profound joy."

 

This timepiece embodies the delicate craftsmanship and aesthetic sensibility unique to Japan, hallmarks of NAOYA HIDA & Co. The realization of this collaboration stems from the resonance between Mr. Hida's long-held admiration for Caliber 135 and ZENITH's vision in reviving this legendary movement for the modern era. It is a model that could only emerge when professionals, holding mutual respect for each other's philosophies and skills, came together.