After introducing the G.F.J. Caliber 135 last year, Zenith has expanded the line with two new models and created a new collection in the process. Following closely in the footsteps of the platinum debut model, the new additions are dressed in 18k yellow gold and tantalum, with richly furnished natural stone dials.

The cal. 135 returns — now finished in a more traditional manner — boasting impressive performance that does justice to the movement’s enviable competition record.

Initial thoughts

The return of the legendary cal. 135 was something I always hoped I’d see, but never thought I would. But in a moment akin to Omega’s recreation of the famed cal. 321 chronograph, Zenith brought back one of the most successful observatory calibres in history.

The movement made its return last year in grand style to mark the brand’s 160th anniversary, well built but priced well above Zenith’s typical domain.

The style was also an acquired taste, with a hand-guilloche chapter ring, with a matching pattern machined into the movement bridges. The dial treatment was one thing, but the finishing of the movement arguably dulled what could have been an ascendant moment.

For 2026, two new dial configurations — bloodstone and onyx — join what can now be called an official collection, both equally as luxe as the model’s blue debut.

Fortunately, when it comes to the cal. 135, Zenith left the brick-style bridge finishing behind, opting for more ordinary — but more attractive — Geneva stripes in their stead.

Bloodstone and onyx

The new G.F.J. models continue the anniversary edition’s theme of combining a mother-of-pearl small seconds sub-dial with a natural stone dial centre. Zenith’s brand colour is blue, which explains the choice to launch in lapis lazuli last year.

The new configurations in 18k yellow gold and tantalum feature dials made from speckled green bloodstone and glossy black onyx, respectively. The former option is available on a solid 18k yellow gold bracelet, while the latter features baguette diamond hour marks.

In either case, the colour-matched brick-style guilloche chapter ring returns. It all adds up to an expensive bill of materials. While it’s true that stone dials can now be had quite cheaply, that can’t be said for multi-piece dials like this that feature numerous decorative techniques and noble materials.

Regardless of case material and dial colour, the 39.15 mm case seems like the sweet spot, creating space for a large and legible sub-seconds scale that doesn’t encroach too much on the chapter ring.

As before the case is water resistant to 50 m, and feels reassuringly robust.

Traditional finishing

Arguably the biggest news is the return to traditional Cote de Geneve for the movement bridges. The cal. 135 already has a lot going for it, and benefits from the simpler treatment.

Zenith set a high bar for itself in terms of execution, and aimed for an equally ambitious price. Perhaps for this reason, the movement is finished to a much higher standard than mainline Zenith calibres.

The movement is indeed finished to haute horlogerie standards in most areas, complete with hand-polished anglage and a few inner angles on the bridges. The selective perlage on the dial side of the mainplate is curious, since the entire plate is concealed by the dial.

The choice to decorate only the centre portion might hint at future open-dial configurations, though there may well be a functional reason for this decision.

Regardless of finishing, the cal. 135 is not a typical time-only movement, and punches above its weight in terms of architecture and performance.

One of the last great round observatory movements, the cal. 135 dominated the Neuchâtel Observatory in the early 1950s. The secret to the movement’s success lies in its massive balance wheel, made possible thanks to an unusual gear train layout.

The recreation of the cal. 135 capture the important details while upgrading a few things to suit contemporary expectations. The two key changes relate to the power reserve, which is now much longer, and the balance staff, which is now shock protected.

The cal. 135, seen here in last year’s 160th anniversary edition.

Zenith rightly chose to emphasise the high-performance nature of the cal. 135 by carefully adjusting each to movement to run within +/- 2 seconds per day. This is the kind of performance typically associated with high-tech silicon hairspring-equipped movements from rivals like Omega and Rolex.

But the cal. 135 is an antique platform made using traditional materials, meaning it requires a more experienced hand to bring out its best.

Key facts and price

Zenith G.F.J. Caliber 135
Ref. 30.1865.0135/56.C216 (bloodstone/yellow gold)
Ref. 98.1865.0135/21.C205 (onyx/tantalum)

Diameter: 39.15 mm
Height: 10.5 mm
Material: 18k yellow gold or tantalum
Crystal: Sapphire
Water resistance: 50 m

Movement: Cal. 135
Functions: Hours, minutes, and seconds
Frequency: 18,000 beats per hour (2.5 Hz)
Winding: Manual
Power reserve: 72 hours

Strap: Alligator strap with pin buckle, yellow gold bracelet available at additional cost.

Limited edition: 161 pieces in 18k yellow gold, 20 pieces in tantalum.
Availability: At Zenith boutiques and authorised dealers.
Price: Upon request

For more, visit Zenith-watches.com