Zenith, G.F.J. – Caliber 135 Continues to Spin the Legend

LE LOCLE / GENEVA, April 14, 2026: Zenith writes a new chapter in its highly acclaimed "G.F.J." collection, which revives a legendary caliber and pursues the essence of chronometry. Named after the initials of Zenith's founder, Georges Favre-Jacot, the "G.F.J." is not merely a re-edition but signifies a return to the origins of high-precision watchmaking. The "G.F.J.", which breathed new life into the legendary Caliber 135 and won the Chronometry Prize at the 2025 Geneva Watch Grand Prix (GPHG), is a contemporary expression of Zenith's historical expertise in observatory timing. And now, Zenith has created a yellow gold "G.F.J." with a striking bloodstone dial, limited to 161 pieces. This timepiece goes beyond the adoption of new materials, reaffirming the "G.F.J." as a central contemporary presence for Caliber 135, which continues to weave its story.

Zenith built its reputation by participating in observatory chronometry competitions from the late 19th century, winning 2,333 awards, surpassing other watch brands. At the heart of this golden age was Caliber 135.

Caliber 135 was specially developed for chronometry competitions and manufactured from 1949 to 1962. The competition version, 135-O, won 235 chronometry prizes and achieved five consecutive first places at the Neuchâtel Observatory from 1950 to 1954. This record remains unbroken.

Zenith's goal was not to reproduce the past but to redesign Caliber 135 for the 21st century. The new caliber maintains its distinctive architecture with a diameter of 13 lignes (30mm), a frequency of 18,000 vibrations per hour, and a large balance wheel with an offset center wheel, while incorporating modern materials and technological innovations to improve performance and reliability.

Caliber 135

The barrel provides approximately 72 hours of power reserve, and the optimized gear train enhances efficiency. The large balance wheel features a regulating screw and a Breguet overcoil. The iconic double-arrow shaped regulating mechanism allows for precise adjustment, and a hacking seconds mechanism has been added for even more accurate time setting. The movement's accuracy, adjusted to within ±2 seconds per day, is COSC certified.

True to its original purpose, the "G.F.J." expresses the essence of Caliber 135, with precision elevated to a design philosophy.

This new "G.F.J." exudes a warmer and more radiant presence.

The 39 mm case is made of yellow gold. Inspired by chronometers made in the 1950s, its slender proportions, stepped bezel, and curved lugs exude refined elegance, while the glow of gold brings a contemporary feel.

Beneath the box sapphire crystal, the dial, which creates a harmony of texture and material, is composed of three parts, just like the original.

- The central disc is made of bloodstone, utilizing the natural veins and inclusions created by nature, ensuring no two dials are alike.

- The large small seconds counter at 6 o'clock uses mother-of-pearl.

- The guilloché pattern along the outer edge is inspired by the brick facade of the Zenith Manufacture in Le Locle, paying homage to Georges Favre-Jacot's vision of a vertically integrated manufacture.

The dial features applied yellow gold markers and precisely faceted hands, completing the harmony between the profound expression inherent in minerals and architectural precision.

Through the sapphire crystal case back, one can admire the decoration of the hand-wound Caliber 135. Here, in a departure from the previous "160th Edition," there is a return to more classical codes, such as hand-beveled, wide Côtes de Genève decoration, and a modern dark ruthenium finish with yellow gold-colored engraving.

The structure, characterized by a large balance wheel and symmetrical arrangement, is maintained in this timepiece. More than just a mechanism, Caliber 135 was designed as a chronometry structure. The "G.F.J." eloquently tells the story of Zenith's pursuit of chronometry.