Few movements have left a mark on watchmaking quite like Zenith’s Calibre 135. Revered by collectors and historians alike, it remains one of the most successful chronometer movements ever created. Now, Zenith continues that story with a striking new interpretation of the G.F.J., pairing the modern Calibre 135 with a distinctive bloodstone dial and an elegant yellow-gold case.
Thank you for reading this post, don't forget to subscribe!Limited to just 161 pieces, the latest G.F.J. is more than a new aesthetic variation. It reinforces the collection’s role as the permanent home of a movement that helped define Zenith’s reputation for precision.
A Movement That Defined an Era
Zenith’s pursuit of chronometric excellence dates back to the late nineteenth century. Over the decades, the manufacture accumulated an unmatched 2,333 chronometry prizes, establishing itself as one of the most accomplished names in precision watchmaking.
At the centre of that success was the Calibre 135.
Produced from 1949 to 1962, the movement was developed specifically for observatory timing competitions. Its competition-specification version, known as the 135-O, earned an extraordinary 235 chronometry awards, including five consecutive first-place victories at the Neuchâtel Observatory between 1950 and 1954, a record that remains unbeaten.
When Zenith introduced the G.F.J. collection in 2025, named after founder Georges Favre-Jacot, it provided a contemporary platform for the rebirth of this historic movement. The collection’s debut was recognised with the Chronometry Prize at the Grand Prix d’Horlogerie de Genève 2025.
Re-Engineering the Calibre 135 for Modern Watchmaking
Rather than simply recreating a vintage movement, Zenith chose to re-engineer the Calibre 135 for contemporary use while preserving the defining characteristics that made it famous.
The hand-wound calibre retains its original 30mm diameter, oversized balance wheel and leisurely frequency of 18,000 vibrations per hour. At the same time, it incorporates modern technical improvements designed to enhance reliability and performance.
The movement now offers a 72-hour power reserve, an optimised gear train, a large balance wheel with regulation screws and a traditional Breguet overcoil hairspring. A stop-seconds mechanism allows precise time setting, while each movement is regulated to an impressive accuracy of ±2 seconds per day and certified by COSC.
Visible through the sapphire caseback, the calibre features broad Côtes de Genève decoration, hand-finished bevels, a dark ruthenium finish and gold-coloured engravings that create an elegant contrast against the movement’s architecture.
The Beauty of Bloodstone
The defining feature of this edition is its remarkable dial.
Zenith maintains the G.F.J.’s signature three-part construction while introducing a centre section crafted from bloodstone, a variety of jasper known for its deep green appearance and naturally occurring red inclusions. Because every stone is unique, no two dials are exactly alike.
The centre section is framed by a finely executed guilloché outer ring inspired by the brick façade of the Zenith Manufacture in Le Locle, a subtle tribute to Georges Favre-Jacot’s vision of vertically integrated watchmaking.
At six o’clock sits an oversized small-seconds display crafted from mother-of-pearl, adding both visual contrast and depth.
Applied yellow-gold hour markers and faceted yellow-gold hands complete the composition, balancing warmth, texture and refinement.
Vintage Proportions with Contemporary Elegance
The G.F.J. Bloodstone Edition is housed in an 18-carat yellow-gold case measuring 39.15mm in diameter and 10.5mm in thickness.
Its stepped bezel, curved lugs and slender profile draw inspiration from mid-century chronometers, while the warm glow of yellow gold gives the watch a distinctly contemporary presence.
The proportions feel particularly well judged, offering vintage elegance without sacrificing modern wearability.
Limited to 161 Pieces
Zenith will produce only 161 examples of the G.F.J. Bloodstone Edition worldwide.
The watch is delivered with three strap options: a beige nubuck alligator strap, a green alligator strap and a black calfskin strap, each fitted with an 18-carat yellow-gold pin buckle. Collectors can also opt for an 18-carat yellow-gold bracelet equipped with a double folding clasp.
G.F.J.
Reference: 30.1865.0135/56.C216
Key points: Rebirth of the Legendary calibre 135. COSC-certified movement. Breguet Hairspring.
Stop-second mechanism. Manual winding. Limited to 161.
Movement: Calibre 135
Frequency: 18,000 VpH (2.5 Hz)
Power reserve: 72 hours
Functions: Hours and minutes in the centre. Small seconds at 6 o’clock.
Finishes: Côtes de Genève with Ruthenium finishing
Material: 18-ct yellow gold
Water resistance: 5 ATM
Case: 39.15mm / Thickness: 10.5 mm / Lug to lug: 45.75 mm
Dial: Signature brick guilloché on the outer ring with a jasper “bloodstone” centre and a mother-ofpearl small-seconds counter.
Hour markers: 18-ct yellow gold applied indices
Hands: 18-ct yellow gold faceted
Bracelet & Buckle: Delivered with a beige nubuck alligator leather strap, a green alligator leather strap and a black calfskin leather strap, fitted with a yellow gold pin buckle. Optional for purchase: 18-ct yellow gold bracelet with double folding clasp.
Final Thoughts
The Zenith G.F.J. Bloodstone Edition succeeds because it focuses on substance rather than nostalgia. The watch celebrates one of the most important chronometer movements ever produced while demonstrating how historical watchmaking achievements can remain relevant today.
The combination of the re-engineered Calibre 135, a unique bloodstone dial and an elegant yellow-gold case results in a watch that feels both rooted in history and entirely contemporary. For collectors who appreciate chronometric excellence and meaningful horological heritage, the latest G.F.J. represents one of Zenith’s most compelling releases of the year.
