Zenith G.F.J. Calibre 135

Zenith marks a significant milestone, its 160th anniversary, by unveiling a special timepiece named G.F.J., honoring the initials of its founder, Georges Favre-Jacot. This release brings a celebrated piece of horological history back into the spotlight: the legendary Calibre 135. More than a simple reissue, the G.F.J. watch houses a thoroughly re-engineered version of this famed movement, designed to meet contemporary standards while preserving the spirit of the original award-winner.

The story of Zenith begins in 1865 in Le Locle, Switzerland. Georges Favre-Jacot harbored a revolutionary ambition for his time: to consolidate all watchmaking professions under one roof, creating a true manufacture. His goal was audacious – to produce 'the perfect watch,' embodying the highest levels of precision, reliability, and craftsmanship. This drive for excellence led him to name his company ZENITH, symbolizing the highest point achievable, a constant reminder of the pursuit of perfection that has guided the brand for over a century and a half.



A crucial part of Zenith's identity and reputation stems from its historical dedication to chronometry. In eras past, observatory trials were the ultimate proving ground for watchmaking prowess. These weren't just about scientific measurement; success brought immense prestige. Observatories like Neuchâtel, Geneva, Kew Teddington, and Besançon served as independent arbiters, verifying the exceptional accuracy watchmakers could attain. Brands eagerly submitted specially prepared movements, knowing that victories translated directly into enhanced reputation and credibility.

Zenith entered these demanding competitions as early as 1897. Over the subsequent decades, the manufacture amassed an unparalleled record, securing 2,333 chronometry prizes – more than any other watch brand. This dedication to precision was a direct fulfillment of Georges Favre-Jacot’s vision: proving that his integrated manufacturing system could produce superior timepieces. The competitions spurred innovation and cemented Zenith's status as a master of accuracy.

Within this illustrious history of prize-winning movements, one calibre stands out: the legendary 135. Conceived by watchmaker Ephrem Jobin under the direction of Zenith's Technical Director, Charles Ziegler, the Calibre 135 was engineered specifically for the rigors of observatory chronometry trials. Its designation derived straightforwardly from its dimensions: 13 lignes (approximately 30mm, the maximum diameter allowed for wristwatches in the Neuchâtel trials) and 5mm thick.

Produced between 1949 and 1962, the Calibre 135 existed in two forms. The standard commercial version (designated 135) was available to the public. However, it was the observatory-specific iteration, the Calibre 135-O, created solely for competition, that forged the legend. This specialized movement accumulated an astonishing 235 chronometry prizes, a record that remains unbroken in watchmaking history.

The Calibre 135-O's most dominant period occurred under the expert regulation of Zenith's renowned "chronométriers," Charles Fleck and René Gygax. Their skill propelled the movement to achieve an extraordinary feat: five consecutive first-place awards in the wristwatch category at the Neuchâtel Observatory trials, spanning from 1950 to 1954. This consistent performance underscored the calibre's exceptional design and the meticulous adjustment it received.



The mystique surrounding the Calibre 135-O experienced a resurgence in 2022. A unique collaboration involving Zenith, independent master watchmaker Kari Voutilainen, and Phillips in Association with Bacs & Russo brought ten original vintage movements from those victorious 1950-1954 years back to life. Voutilainen meticulously restored and exquisitely decorated these historic calibres, housing them in an extremely limited series that captivated high-end collectors and reignited fascination with the 135-O.

Building on this renewed appreciation, Zenith decided to fully resurrect the Calibre 135, not just restore vintage examples, but re-engineer it for the 21st century. This endeavor resulted in the movement powering the new G.F.J. anniversary watch. While this modern iteration faithfully adopts the architecture, dimensions, and visual identity of its ancestor, it is not merely a replica. It represents a thoughtful modernization incorporating contemporary technical solutions and materials where beneficial.

The new Calibre 135 retains the key architectural elements that defined the original, including the offset center wheel which creates the necessary space for an oversized balance wheel. This large balance wheel was a critical factor in the original's stability and precision, and it remains a central feature. The movement operates at a frequency of 2.5 Hz, or 18,000 vibrations per hour, a rate characteristic of classic chronometers.

Significant technical upgrades enhance the performance and user experience of the modern Calibre 135. The power reserve has been substantially increased from the original's approximately 40 hours to a robust 72 hours, thanks to improvements in the mainspring barrel. The gear train has also been optimized, employing updated tooth geometry for more efficient power transmission.

Further refinements include the balance wheel, which now features regulation screws for fine adjustment, paired with a Breguet overcoil hairspring for improved isochronism. The distinctive double arrow-shaped regulator, a signature of the 135-O allowing for precise rate adjustments, is faithfully retained. A crucial modern addition is a stop-second mechanism, allowing the wearer to halt the seconds hand for exact time-setting. To enhance durability, the balance staff pivots are now protected by spring-mounted jewel settings (shock protection).



Each new Calibre 135 movement is meticulously regulated to achieve a precision of +/-2 seconds per day, performance officially certified by the Contrôle Officiel Suisse des Chronomètres (COSC), upholding the chronometric legacy of its namesake. Comprising 157 components, the movement showcases sophisticated finishing that reflects its pedigree.

The decoration of the new Calibre 135 pays homage to Zenith's heritage. The bridges feature a distinctive "brick" guilloché pattern, a motif inspired by the unique red and white brick facade of the historical Zenith Manufacture building. This pattern subtly incorporates the initials G.F.J., further linking the watch to the founder. Other finishing details include a circular satin finish on the barrel and a black-polished crown wheel, while the use of large jewels adds a final touch of refinement.

The watch housing this revived movement, the G.F.J., is designed to echo the aesthetic sensibilities of the 1950s, the era when the original Calibre 135 reigned supreme. The case, crafted from Platinum 950, measures a restrained 39.15mm in diameter, with a thickness of 10.5mm and a lug-to-lug distance of 45.75mm. These proportions contribute to a slender and wearable profile suitable for various wrist sizes.

The platinum case exhibits sophisticated detailing. It features a stepped bezel design, adding visual depth, and elegantly curved lugs that are also stepped, creating a sculptural flow. The case surfaces display a pleasing contrast between meticulously brushed and highly polished areas. The notched winding crown is subtly engraved with the G.F.J. initials. The watch offers a practical water resistance of 5 ATM (50 meters).

Protected by a box-shaped sapphire crystal, the dial of the G.F.J. is a complex and visually rich creation in Zenith's signature blue hue – a color connecting the brand to its name and the pursuit of precision under the stars. The dial employs a three-part construction, lending it considerable depth. The outermost ring features the same intricate "brick" guilloché pattern seen on the movement bridges, serving as a textured backdrop for the applied hour markers.



These hour markers are faceted indices crafted from 18-carat white gold. Between them runs a discreet minute track composed of 40 individual white gold beads, painstakingly applied by hand. The central section of the dial is made from a disc of Deep Blue Lapis Lazuli. This natural stone is known for its inclusions of pyrite, which create glittering gold-colored flecks, reminiscent of a starry night sky. The inherent variations in the stone ensure that each dial possesses a unique character.

Completing the dial layout is the oversized small seconds subdial positioned at 6 o'clock. This subsidiary dial is crafted from mother-of-pearl, its natural iridescence providing a subtle contrast to the Lapis Lazuli and the guilloché ring. Time is indicated by slim, baton-style hands made from 18-carat white gold, maintaining the watch's refined aesthetic.

The Zenith G.F.J. is delivered with a versatile selection of three straps. Included are a dark blue alligator leather strap, a classic black calfskin leather strap, and a blue calfskin strap with a textured "Saffiano" finish. These straps attach via a platinum pin buckle, which is engraved with both the G.F.J. initials and the recurring brick pattern motif. For those desiring a full metal look, a seven-row platinum bracelet is available as an optional purchase; its center links are embossed with the brick pattern, echoing the dial and movement decoration.

According to Romain Marietta, Zenith's Chief Product Officer, the design process for the G.F.J. centered on achieving a balance between faithfulness to the 1950s source material and contemporary refinement. The goal was to honor Georges Favre-Jacot's legacy while creating a watch appealing to both vintage enthusiasts and modern collectors. The brick pattern serves as a subtle yet meaningful reference to the Manufacture's architecture and Favre-Jacot's pioneering integration of production processes.

Laurence Bodenmann, Zenith's Head of Heritage, emphasizes the historical context, noting that observatory trials were paramount for establishing a brand's technical mastery in an era focused on mechanical precision. She highlights the Calibre 135's unique status, particularly the 135-O variant, attributing its iconic standing largely to its innovative architecture centered around the extra-large balance wheel, a feature designed for superior inertia and stability. The design influence of the 1950s, characterized by clean lines and balanced proportions, informed the original chronometers and is carried forward, refined for today, in the G.F.J.



Zenith CEO Benoît de Clerck encapsulates the project's significance: "Few movements in watchmaking history have achieved the level of chronometric excellence and recognition as the calibre 135... Bringing it back for our 160th anniversary is about honoring this legacy while sharing it with a new generation of collectors. With the G.F.J., we have reimagined this legendary movement... offering a contemporary interpretation that resonates with today’s spirit."

The Zenith G.F.J., reference 40.1865.0135/51.C200, is presented as an exclusive limited edition commemorating the brand's 160th anniversary. Production is strictly limited to 160 pieces worldwide. The watch is priced at $49,900 USD / 48,900 CHF / 52,900 Euros. It is available for pre-order through Zenith's physical boutiques, its online e-commerce platform, and authorized Zenith retailers globally.

Case: Platinum 950; Diameter 39.15mm; Thickness 10.5 mm; Lug-to-lug 45.75 mm; Water resistance 5 ATM; Stepped bezel and curved stepped lugs; Notched crown with G.F.J. initials; Alternating brushed and polished finishes.

Movement: Calibre 135 manual winding; Frequency 18,000 VpH (2.5 Hz); Power reserve 72 hours; 157 components; COSC certified; Breguet hairspring; Stop-second mechanism; Exclusive 160th Anniversary "Bricks" guilloché finishing on bridges.

Dial: Blue three-part construction; Outer ring with blue "bricks" guilloché pattern; Center section in Lapis Lazuli; Oversized small seconds subdial at 6 o'clock in mother-of-pearl; Hour markers are 18-ct white gold applied indices; Hands are 18-ct white gold faceted.

Strap: Comes with 3 straps: Dark blue alligator leather strap with platinum pin buckle, black calfskin leather strap, blue “Saffiano” calfskin leather strap; Platinum pin buckle engraved with G.F.J initials and brick pattern; Optional seven-row platinum bracelet available for purchase.

Price: $49,900 USD / 48,900 CHF / 52,900 Euros.

Reference Number: 40.1865.0135/51.C200

Notes: Limited edition of 160 pieces celebrating Zenith's 160th Anniversary; Features the rebirth of the legendary Calibre 135 chronometer movement; Named G.F.J. after founder Georges Favre-Jacot; Features special "bricks" guilloché finishing on movement and dial inspired by the Zenith Manufacture facade.