When Zenith brought back the legendary Calibre 135 last year in the G.F.J. collection, it was a tribute to its 160-year history. Also, it signalled the return of one of the most celebrated chronometer movements. Now, the brand expands the collection with two new G.F.J interpretations: a tantalum edition with an onyx dial and diamonds, and a warmer yellow-gold model featuring a striking bloodstone dial.
The Calibre 135
Both watches continue the story of the Calibre 135, a movement originally developed in the late 1940s specifically for observatory chronometry competitions. Created by watchmaker Ephrem Jobin, the calibre was designed with a large barrel to deliver stable power and an oversized balance wheel to maximise rate stability and featured an offset centre wheel to free space for the large regulator system. Produced between 1949 and 1962, the calibre 135 existed in both a commercial version and a competition-grade 135-O. The latter became one of the most successful chronometer movements ever produced. Carefully prepared by Zenith’s chronométriers Charles Fleck and René Gygax, the 135-O won more than 230 observatory prizes and secured five consecutive first places at the Neuchâtel Observatory from 1950 to 1954, a record that still stands.
The new hand-wound Calibre 135, re-engineered for modern production, retains the distinctive construction and 13-ligne diameter, but incorporates contemporary technical improvements. The barrel now delivers a power reserve of approximately 72 hours, the gear train has been optimised for efficiency, and the movement now includes hacking seconds. The oversized balance still beats at 18,000 vibrations/hour and features regulation screws, a Breguet overcoil hairspring, and the characteristic double-arrow-shaped regulator for fine adjustment. Each movement is COSC-certified and regulated to a daily precision of ±2 seconds.
The G.F.J. in Tantalum
The most exclusive interpretation of the G.F.J. comes in a 39.5mm case made from tantalum, a metal rarely used in watchmaking due to its density and difficulty in machining. With its natural blue-grey tone and soft metallic sheen, tantalum gives the watch a distinctive character, restrained and technical.
The dial follows the collection’s established three-part design. A polished black onyx centre creates a deep, mirror-like surface, contrasted by an oversized small-seconds counter in grey mother-of-pearl. Surrounding the dial is the signature brick-pattern guilloché ring inspired by the façade of the Zenith manufacture in Le Locle. Eleven baguette-cut diamond indices maintain the monochrome look. Visible through the sapphire caseback, the movement features Geneva stripes, hand-chamfered bridges, and a dark ruthenium finish that matches the tone of the tantalum case.
Quick facts – 39.15mm x 10.5mm tantalum case – stepped bezel and sculpted lugs – sapphire crystal front and back – 50m WR – three-part construction dial – brick-pattern guilloché outer ring – black onyx centre – grey mother-of-pearl small seconds at 6 o’clock – baguette-cut diamond hour markers – 18k white gold faceted hands – Zenith Calibre 135 – manual-winding – COSC-certified chronometer – oversized balance with regulation screws – Breguet overcoil hairspring – double arrow-shaped regulator – stop-seconds mechanism – 18,000 vibrations/hour – 72-hour power reserve – blue nubuck alligator strap with titanium pin buckle – additional black alligator strap and grey calfskin strap – limited edition of 20 pieces – Ref. 98.1865.0135/21.C205 – CHF 73,900.
The G.F.J. in Yellow Gold
The second new Zenith G.F.J. model is crafted in 18-carat yellow gold. While the case design remains identical, measuring 39.5mm with a stepped bezel and curved lugs, the gold brings a much warmer feeling to the watch.
The dial remains true to the original concept but introduces a new element, a central disc in bloodstone, a form of green jasper with natural red inclusions. An oversized mother-of-pearl small-seconds counter is at six o’clock; the outer sector retains the brick-pattern guilloché. Through the sapphire caseback, the re-engineered Calibre 135 reveals a decoration that differs slightly from the earlier anniversary model. Here, the bridges feature broader Geneva stripes, refined hand-chamfering and a dark ruthenium finish with gold-coloured engravings.
Quick facts – 39.15mm x 10.5mm 18k yellow gold case – stepped bezel and curved lugs – sapphire crystal front and back – 50m WR – dial with brick-pattern guilloché outer ring – bloodstone (jasper) centre – mother-of-pearl small seconds at 6 o’clock – applied yellow-gold indices – yellow-gold faceted hands – Zenith Calibre 135 – manual-winding – COSC-certified chronometer – Breguet overcoil hairspring – stop-seconds mechanism – 18,000 vibrations/hour – 72-hour power reserve – beige nubuck alligator strap with yellow-gold pin buckle – additional green alligator strap and black calfskin strap – optional yellow-gold bracelet – limited edition of 161 pieces – Ref. 30.1865.0135/56.C216 – CHF 48,900.
Both new Zenith G.F.J. watches are available by pre-order only. For more information, please visit Zenith-Watches.com.
https://monochrome-watches.com/first-look-zenith-gfj-georges-favre-jacot-calibre-135-tantalum-black-onyx-yellow-gold-bloodstone-specs-price-live-pics/