After reviving the iconic Calibre 135 earlier this year, Swiss watchmaker Zenith is proving that you can teach an old dog new tricks. The legendary producer has just taken out the Chronometry award at the Grand Prix d’Horlogerie de Genève (GPHG) for its stunning G.F.J. Calibre 135.
With 2025 marking the maison’s 160th anniversary, success for legendary watchmaker Zenith felt all but written in the stars. Many expected the milestone year to deliver a series of heritage revivals, and while speculation circled around the famed El Primero movement, the Swiss icon had something else in mind.
At Watches & Wonders earlier this year, CEO Benoît de Clerck introduced the G.F.J. Calibre 135; a stunning halo piece that paid tribute to one of the maison’s most intricate, yet often overlooked, innovations. Six months down the track and de Clerck’s vision has paid off.
Just last week at the Grand Prix d’Horlogerie de Genève (GPHG), Swiss watchmaking’s most important night, the Zenith G.F.J. Calibre 135 received the award for outstanding work in the field of chronometry.
What is the GPHG?
Often described as the ‘Oscars of Watchmaking’, the GPHG is an annual international awards ceremony that celebrates the most remarkable and innovative watches of the past 12 months.
Twenty-nine jury members, comprised of a mix of media, retailers, and watchmaking brands without nominated pieces, vote on their top releases in the fields of Tourbillon, Men’s Complication, Date Only and 12 more enticing categories.
This year, under the careful guidance of jury president Nick Foulkes, the GPHG honoured a broad range of maisons, rewarding the watchmakers willing to break boundaries and experiment with new case materials, design philosophies and movement construction. However, when it came time for the top honours, two historic brands, each celebrating a milestone year, rose above.
Fan favourite Breguet secured the Aiguille d’Or, the event’s grand prize, for its Classique Souscription, while the Zenith G.F.J. Calibre 135 nabbed the award for Chronometry, the science of accurate time measurement.
Zenith’s Achievement in Chronometry
A tribute to founder, Georges Favre-Jacot, the Zenith G.F.J. Calibre 135 is a piece of horological history wrapped up in modern engineering. The timepiece features a historically award-winning chronometer Calibre 135 movement, which the brand claims has been restored and hand-finished to ‘perfection’.
Designed by Ephrem Jobin at the request of Charles Ziegler, technical director of Zenith, the chronometer Calibre 135 was produced from 1949 to 1962, for the sole purpose of competing in chronometry competitions at the Observatories of Neuchâtel, Geneva, Kew Teddington and Besançon.
“The Calibre 135 holds a truly exceptional place in Zenith’s history and in the broader landscape of watchmaking,” Laurence Bodenmann, head of heritage of Zenith Watches explained.
“Developed specifically for observatory competitions (135-O), it became the most awarded movement during the golden age of chronometry trials…What sets it apart is its extra-large balance wheel, which brings more inertia and shapes its entire architecture in a way never seen before.”
In 2025, to mark the maison’s 160th anniversary, Zenith revived the iconic movement, albeit with some slight alterations. The new version uses the same dimensions, offset centre wheel and oversized balance wheel as its predecessor, however, also incorporates a new gear train with refined tooth geometry.
Further to that, the updated Calibre 135 delivers 72 hours of power reserve compared to 40 hours in the 1950s version, a Breguet overcoil on the balance wheel and a stop-second mechanism that allows the wearer to set the time to the exact second.
According to Romain Marietta, CPO of Zenith Watches, the reimagined Calibre 135 is more of a continuation of the philosophy than it is a remake. The challenge was modernising the movement while still maintaining a connection to the past.
“While remaining faithful to the spirit and character of the original, the new calibre has been thoughtfully re-engineered to meet contemporary expectations,” Marietta said.
“It benefits from subtle yet meaningful improvements that enhance its reliability, precision, and overall performance without compromising its true essence. The result is a movement that seamlessly blends the charm of its historical roots with modern advancements, ensuring it remains relevant and captivating for today’s discerning collectors.”
Technically precise, COSC-certified and delightfully adorned with guilloché finishing on the bridges, the Calibre 135 movement is a special piece of equipment. What’s more, it has a case to match.
Zenith G.F.J. Calibre 135
Designed to capture the essence of 1950s design, the Zenith G.F.J. Calibre 135 features a slender 39mm platinum round case highlighted by a stepped bezel and curved stepped lugs. The timepiece’s thin profile is contrasted by a stunning notched crown emblazoned with the G.F.J. initials.
These elements slowly draw your eye to the inner dial and this is where Zenith shows strength. The G.F.J. Calibre 135’s enchanting blue lapis lazuli dial is the star attraction, replete with gold-coloured pyrite flecks that invariably speak to the brand’s namesake. Adding to this are faceted white gold hour markers, a discreet minute track of 40 white gold beads applied by hand and an oversized subdial at 6 o’clock in mother-of-pearl.
“Few movements in watchmaking history have achieved the level of chronometric excellence and recognition as the Calibre 135,” Zenith CEO Benoît de Clerck said. “More than just a technical achievement, it became a true icon of precision. Bringing it back for our 160th anniversary is about honouring this legacy while sharing it with a new generation of collectors.”
“With the G.F.J., we have reimagined this legendary movement, not simply as a nod to the past, but as a way to share a defining part of its heritage while offering a contemporary interpretation that resonates with today’s spirit, and we are deeply proud of it.”
What the Win Means for Zenith
The win not only represents a landmark moment in what has already been a remarkable year for Zenith, but also points to a renewed focus on innovation.
For the past five years, Zenith has been locked in a Defy-spiral, releasing seemingly endless iterations of its dodecahedron-shaped integrated bracelet release. While some, such as the Defy Skyline Chronograph and vintage-inspired Defy Revival, have faithfully continued the range’s unique legacy, many have been underwhelming.
CEO Benoît de Clerck’s ambitious decision to bring back the Calibre 135 earlier this year signalled a change of tack, and it has undoubtedly paid off. The G.F.J. Calibre 135 is an understated piece of horological ingenuity that speaks to Zenith’s incredible contribution to the world of fine watchmaking. Everything, from the finishing down to the internal mechanics, is refined to a level of meticulous compulsion.
More than 160 years after founder Georges Favre-Jacot established the business, Zenith is proving that great design never goes out of style. If the G.F.J. Calibre 135 is anything to go by, the sky truly is the limit for this historic watchmaker.
Released in a limited edition of 160 pieces, the G.F.J is available for pre-order exclusively from the brand’s physical and online boutiques, as well as through authorised retailers worldwide. It is priced at CHF 48,900 and comes with three different straps: a dark blue alligator leather strap, a black calfskin leather strap, and a blue “Saffiano” calfskin leather strap.
Zenith G.F.J. Calibre 135 Technical Specifications
- Brand: Zenith
- Model: G.F.J. Calibre 135
- Reference: Ref. 40.1865.0135/51.C200
- Diameter: 39.15mm
- Thickness: 10.15mm
- Lug-to-Lug: 45.75mm
- Case Material: 950 platinum case
- Movement: Calibre 35 Hand Wound
- Power Reserve: 72 hours
- Water-Resistance: 50 metres
- Availability: Limited edition of 160 pieces
- Price: CHF 48,900
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