ZENITH G.F.J. 2026: The Ultimate Expression of Calibre 135 Chronometry

A modern revival of the most awarded chronometer movement in watchmaking history

The ZENITH G.F.J. 2026 withe the Calibre 135, unveiled at Watches and Wonders 2026 with a powerful statement: a continuation of the legacy of the legendary Calibre 135. Named after founder Georges Favre-Jacot, the G.F.J. is not merely a tribute to the past, but a contemporary platform dedicated to pure chronometric excellence.

Following its award-winning revival, including the “Chronometry Prize” at the Grand Prix d’Horlogerie de Genève in 2025, the collection expands with two remarkable new executions: a refined yellow gold edition limited to 161 pieces and an ultra-exclusive tantalum version limited to just 20 pieces.

The Legacy of the Legendary Calibre 135

The story of the Calibre 135 is deeply rooted in ZENITH’s historic dominance in observatory chronometry competitions. Between the late 19th century and mid-20th century, the brand accumulated an unmatched 2,333 chronometry prizes, with the Calibre 135 at the center of this achievement.

Produced between 1949 and 1962, its competition variant, the 135-O, secured 235 awards, including five consecutive first prizes at the Neuchâtel Observatory. This record remains unmatched, cementing the calibre as one of the most accurate mechanical movements ever created.

Rather than simply reproducing the original, ZENITH has re-engineered the Calibre 135 for the modern era. While preserving its distinctive architecture, including its oversized balance wheel and off-centre layout, the updated movement integrates contemporary materials and engineering solutions to enhance precision, reliability, and performance.

Modern Engineering Meets Historic Precision

The modern Calibre 135 maintains its classic 13-ligne (30mm) diameter and operates at 18,000 vibrations per hour, staying faithful to its origins. However, significant technical upgrades have been introduced.

The movement now offers a 72-hour power reserve, improved gear train efficiency, and a large balance wheel equipped with regulation screws and a Breguet overcoil. The signature double-arrow regulator enables fine adjustment, while a stop-seconds mechanism allows precise time setting.

Each movement is regulated to an impressive accuracy of +/- 2 seconds per day and is officially COSC-certified, reinforcing the G.F.J.’s position as a true chronometer in the purest sense.

The Yellow Gold Edition: A Contemporary Classic

The standard 2026 edition of the G.F.J. is presented in a 39.5mm yellow gold case, combining vintage-inspired proportions with modern refinement. The stepped bezel and curved lugs evoke mid-20th-century chronometers while maintaining a contemporary presence.

The dial features a sophisticated three-part construction. At its center lies a striking bloodstone disc, ensuring each watch is visually unique due to its natural variations. At 6 o’clock, an oversized small seconds counter in mother-of-pearl adds contrast, while the outer guilloché ring draws inspiration from the brick façade of the ZENITH Manufacture.

This version is limited to 161 pieces, reinforcing its exclusivity while remaining accessible to collectors seeking a modern interpretation of classic chronometry.

The Tantalum Edition: Precision in Its Rarest Form

Pushing the concept further, ZENITH introduces an ultra-exclusive version crafted in tantalum, one of the most challenging metals in watchmaking. Limited to just 20 pieces, this edition represents the most refined and technically demanding expression of the G.F.J.

Tantalum is known for its density, corrosion resistance, and distinctive blue-grey hue. However, its hardness makes it extremely difficult to machine and finish, requiring specialized expertise and meticulous craftsmanship.

The dial adopts a more restrained and architectural aesthetic, featuring a black onyx center, a grey mother-of-pearl small seconds display, and a guilloché outer ring. Eleven baguette-cut diamond indexes add a subtle yet precise brilliance, enhancing the watch’s refined and minimalist character.

A Movement Designed as a Chronometric Structure

At the heart of both editions lies the Calibre 135, visible through the sapphire caseback. Its finishing reflects a balance between tradition and modernity, with Côtes de Genève, hand-chamfered edges, and a dark ruthenium treatment that enhances depth and contrast.

More than a mechanical engine, the movement is conceived as a complete chronometric structure, where every component contributes to precision and stability. The oversized balance and symmetrical architecture reinforce its identity as a purpose-built chronometer movement.

Technical Specifications

A New Chapter in Pure Chronometry

The ZENITH G.F.J. collection reaffirms the brand’s historic expertise in precision watchmaking while demonstrating its ability to reinterpret its legacy for the modern era.

By placing the Calibre 135 at the center of its design philosophy, ZENITH elevates chronometry from a technical objective to an aesthetic and conceptual statement.

With the introduction of both the refined yellow gold edition and the ultra-rare tantalum version, the ZENITH G.F.J. Calibre 135 stands as one of the most refined chronometer-focused releases at Watches and Wonders 2026.

For more information, please visit the official ZENITH website.

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