Zenith G.F.J. Calibre 135

Zenith G.F.J. Calibre 135 Watch Review

The Zenith G.F.J. Calibre 135 was unveiled at Watches & Wonders 2025, coinciding with the brand’s 160th anniversary. Angus Davies explores the watch in detail and explains why, despite seeing many wonderful creations in Geneva, the G.F.J. is in his ‘Top 5’ for 2025.

Watches – appearance and scale don’t always denote excellence

From a young age, I’ve always had an unhealthy relationship with food. I can still hear my father say, ‘your eyes are bigger than your belly’ as I devoured a huge plateful of biscuits. Whenever I  attended a family function, confronted with a vast buffet, I often saw it as a challenge to consume my body weight in sausage rolls and chocolate gateaux. So far, so obese.

Legend has it that in the 1st century, Marcus Gavius Apicius, a wealthy Roman merchant, author and gourmet, coined the phrase, ‘You eat with your eyes first’. However, based on personal experience, I would always counsel caution. For instance, on one occasion, I visited my Auntie Tina’s house to attend my cousin’s birthday party. Surveying the impressive cakes on display, I gutsily tucked in, only to discover they were tasteless at best and, in some instances, plain horrible. With wisdom comes the realisation that appearance and scale don’t always denote excellence. Likewise, when I see a new watch, I’ve learnt to exercise caution before voicing an opinion.

In my ‘Top 5 releases of Watches & Wonders 2025’

Back in April, I strolled through the halls of Watches & Wonders, attending various press presentations and having numerous one-to-one meetings with brands. In some cases, I’d see a timepiece only to discover, upon closer examination, it lacked any substance, reminding me of Auntie Tina’s catering. Inevitably, I kept on walking. Thankfully, many horological delicacies on display were not just good to look at, they were also rich in virtue. Moreover, alongside the many sublime watches that I could easily have taken home, there were also a handful that stood out as truly exceptional, including the Zenith G.F.J. Calibre 135. Since returning to Blighty, I’ve reflected on its design, materials and execution many times. Put simply, this watch is in my ‘Top 5 releases of Watches & Wonders 2025’ and is a timepiece deserving of your attention. I’ll return to the model in due course, but first of all, it is incumbent upon me to say a little more about the watch brand from Le Locle that’s currently celebrating its 160th anniversary.

UNESCO World Heritage Sites (2009)

From the mid-18th century, some farmers living within the Swiss Jura began to supplement their income by making watch components during the harsh winter months. This led to specialisation, with individuals, and ultimately small firms, focussing on the making of specific components such as dials, cases, etc. These parts were subsequently supplied to établisseurs who brought everything together to make complete watches. This business model was widely adopted throughout the watch industry within the region. As a result, the towns of Le Locle and nearby La Chaux-de-Fonds focussed primarily on watchmaking. This influenced the cityscape of each town. Long streets, arranged in a grid-like formation, played host to buildings endowed with expansive windows that would drink in natural light, illuminating watchmakers’ benches. The unique architecture and urban planning, dedicated to the making of watches, led to both towns becoming UNESCO World Heritage Sites in 2009.

Zenith depuis 1865

In 1865, George Favre-Jacot (1843-1917) established the Zenith Manufacture in Le Locle. Having observed industrial production in the US, he chose to set aside the customary practice of specialisation, preferring to house all watchmaking professions under one roof. By adopting this approach, he could enjoy greater economies of scale and achieve better product consistency.

Image – George Favre-Jacot (1843-1917)

Over the years, his Manufacture grew in size. Indeed, according to Zenith, ‘..the Manufacture became the largest in the Neuchâtel mountains, spanning across an area of 9,300 m²/100,100 ft² and comprising 18 buildings. By the dawn of the 20th century, over 600 artisans, driven by the same pursuit of excellence, were already producing 100,000 watches a year there.’ This latter figure is particularly impressive for an era pre-dating computers, CAD systems, CNC machines, wire-erosion machines, etc.

Originally known as ‘G.F.J. & Cie’, before being renamed Zenith, the company gained an esteemed reputation for making chronometers and chronographs. Indeed, if you asked a purist to name an iconic self-winding chronograph, they may well reply ‘El Primero’. Bursting onto the watch scene in 1969, this movement featured a balance operating at 5 Hz, a technical achievement most brands have yet to match.

Image – Zenith El Primero advert (circa 1969) 

Approximately 10 years ago, I visited the Zenith Manufacture in Le Locle. This imposing building with its huge windows features white exterior walls punctuated with Monsieur Favre-Jacot’s initials and incorporates large rectangular sections of red brick. Within the confines of the Manufacture there is much in-house expertise. Indeed, it’s no accident that the Swiss marque has supplied several revered watch brands with its exceptional movements.

Image – the Zenith Manufacture

Now, to coincide with its 160th anniversary, the Swiss marque has released several new models, including my personal favourite, the Zenith G.F.J.

G.F.J. Calibre 135 – introduction

Bearing the initials of Zenith’s founder, the G.F.J. is equipped with a modern-day reinterpretation of the Manufacture’s legendary Calibre 135. This hand-wound movement, made from 1949 to 1962, was produced in two specifications – the ‘commercial variant’ (135) and a special specification for observatory chronometer trials (135-O). This latter specification ‘received 235 chronometry prizes, an absolute record in the history of watchmaking’. Interestingly, the name of the Calibre 135 was inspired by its dimensions, 13 lignes in diameter (29.326 mm) and 5 mm in thickness.

I will return to the movement in due course but, upholding ESCAPEMENT convention, I will begin by looking at the dial of the new Zenith G.F.J. Calibre 135.

Zenith G.F.J. Calibre 135 – dial

At first glance, the dial may appear simple: hours, minutes and small seconds. Likewise, the presence of baton-style hands teamed with applied batons reinforces this perception of simplicity. However, close examination of the dial reveals numerous subtle details that coalesce to form a sumptuous and harmonious aesthetic.

Returning to the hands, they are formed of white gold and paired with facetted white gold hour markers, indicating the prevailing time. Four gold beads nestle between each hour marker, visible yet discreet. The hour track is adorned with a ‘blue bricks guilloché’ motif, a detail inspired by the aforementioned bricks gracing the exterior of the Manufacture. This intricately textured surface adds depth to the dial and endows the hour track with episodes of brilliance and shade.

The central area of the dial is formed of lapis lazuli, a complex aggregate of lazurite, calcite, and pyrite. No two pieces of stone are the same, conferring a degree of exclusivity, a quality much appreciated by luxury watch buyers. The small seconds is shown on a recessed counter formed of blue-toned mother-of-pearl.

This intricate marriage of materials and finishes doesn’t inhibit time-telling. On the contrary, the dial is effortlessly simple to read while at the same time proving fascinating to behold.

Zenith G.F.J. Calibre 135 – case

The case is comparatively understated. Indeed, to the untrained eye, it could easily be mistaken for steel. However, the watch’s notable heft and its whitish cast are clues to its noble standing. Formed of platinum 950, the case feels wonderful upon the wrist (that’s my wrist in the picture below).

Image – watch affixed to the wrist of Angus Davies (19 cm circumference)

Measuring 39.15 mm in diameter with a thickness of 10.5 mm, the dimensions of the Zenith G.F.J. Calibre 135 should suit the majority of wrists and tastefully sidestep showiness.

Once again, when viewing the execution of the housing, initial thoughts of simplicity are soon swept aside. The dial sits beneath a sapphire glass box, a period-inspired detail that floods the dial plain with an abundance of light. A stepped bezel encircles this glazing and features alternating brushed and polished surfaces. Moreover, the bezel, case and lugs feature numerous facets that beautifully toy with light.

Even the crown is an object of beauty. Its notched grip grants a smile-inducing tactility and Monsieur Favre-Jacot’s initials are presented in relief on the vertical flank. To the rear of the case, a pane of sapphire crystal grants sight of the Calibre 135.

The watch is supplied with three straps: a dark blue alligator leather strap, a black calfskin leather strap and a blue ‘Saffiano’ calfskin leather strap. A platinum pin buckle secures the watch to the wrist and, once again, features said ‘brick pattern’. For an additional charge, Zenith also offers a seven-row platinum bracelet adorned with a ‘brick pattern’. While it is beautifully made, I prefer the warmth and understated appearance of the leather straps, albeit I’m sure not everyone will agree with my opinion.

Zenith G.F.J. Calibre 135 – hand-wound movement

Calibre 135 – improvements

Turn the watch over and you will discover a glorious sea of horological loveliness. The movement exhibits a vintage charm that’s clearly been breathed upon by Zenith’s highly accomplished team.

Formerly containing 19 jewels, the new generation Calibre 135 features 22 jewels, an upgrade that will inevitably mitigate friction and wear. The balance staff now sits in spring-mounted jewel settings and Zenith has revisited the gear train, optimising the teeth design, thereby increasing efficiency. Also, the brand has equipped the new generation movement with a modern-day Bioflex mainspring. Collectively, these changes have boosted the power-reserve from approximately 40 hours to 72 hours. Another refinement is the addition of a stop-second mechanism, providing the wearer with the means to synchronise the watch with a reference clock or watch.

Calibre 135 – the balance wheel

Despite enhancing the performance of the Calibre 135, it has not lost any of its period charm. With a cadence of 18,000 vph (2.5 Hz), a comparatively pedestrian tempo, the Calibre 135 sips energy in comparison to its thirstier modern-day 4 Hz counterparts.

Low-frequency movements can be more susceptible to external influences, such as shocks, which can adversely affect precision. However, in this instance, the balance wheel fitted to the new Calibre 135 is notably large, benefiting from greater inertia, making it less susceptible to shocks, etc.

Another attribute of the Calibre 135 is that the huge balance wheel, with its frequency of 2.5 Hz, heightens the visual spectacle of it when in flight. The scale of the balance wheel also means it can accommodate more regulation screws, allowing precise setting of the rate. The movement also features a traditional double arrow-shaped regulator for fine-tuning the rate.

Calibre 135 – Breguet overcoil

As you will have already ascertained, the Zenith G.F.J. Calibre 135 is a purist’s watch. Every aspect has been conceived to sate the desires of horophiles. The balance spring is endowed with a Breguet overcoil. In 1795, Abraham-Louis Breguet (1747-1823) had the inspired idea of upraising the balance spring’s outer coil and reducing its curvature. Breguet’s invention causes the balance spring to breathe more concentrically, augmenting isochronism. This enhancement is typically the preserve of high-end movements, a box that the Calibre 135 ticks with a big, indelible marker.

Calibre 135 – additional highlights

The hand-wound movement is beautifully finished. The bridges are adorned with a becoming ‘brick guilloché’ finish, a motif that proffers a three-dimensional allure and serves as a charming alternative to the traditional Côtes de Genève motif. The edges of the bridges are hand bevelled, the barrel is adorned with a circular satin finish and the crown wheel is black polished, the most prized form of finishing, beloved by watch aficionados.

Upholding the legacy of the historic Calibre 135, the latest specification movement is COSC-certified. However, as you would expect of Zenith, a brand that was founded on the notion of making ‘the perfect watch’, the Calibre 135 surpasses the requirements of COSC and is ‘regulated to be precise within +/- 2 seconds per day’.

Zenith G.F.J. Calibre 135 – closing remarks

The G.F.J. delivers an interesting duality of simplicity and complexity. On one hand, its inventory of functions is comparatively short and yet, on the other hand, its ultra-refined execution is complex and the product of much thought.

While the dial and case brim with attributes, it is the Calibre 135 that steals the show. Inspired by the past, imbued with an array of period details and enhanced with the benefit of modern-day materials and know-how, it is stunning. However, having expended vast amounts of time and effort, I find it hard to believe that once all 160 examples of the Zenith G.F.J. are sold, we will never see the Callibre 135 again. I hope that Zenith employs the new-generation Calibre 135 in some future releases. Indeed, this movement deserves to breathe for decades to come.

All too often in life, we blindly fixate on foods based solely on appearance. Furthermore, we are drawn to ‘supersize’ and ‘kingsize’ without due consideration to taste, smell or texture. Similarly, when we consider a watch, it’s not simply about size or appearance. A fine watch deserves more than a cursory glance. Indeed, it is the nuanced arrangement of materials, textures, depths, colours, finishes and mechanical virtuosity that must be fully evaluated to arrive at a considered opinion. Needless to say, the Zenith G.F.J. delivers a multitude of attributes, all contained in one stunning ownership proposition and it is for this reason that I place it in my ‘Top 5 releases of Watches & Wonders 2025’.