Longines Ultra-Chron Classic automatic silver dial steel bracelet 37 mm

Ultra-Chron: A Legacy of Precision

The history of Longines is closely tied to the pursuit of precision, a value that shaped its reputation from the early 20th century. As early as 1910, the winged hourglass brand filed a patent for a pocket chronograph capable of measuring 1/10th of a second — a remarkable achievement for the time, made possible by a movement beating at 5 Hz (10 vibrations per second). This innovation marked the starting point of a long tradition in the field of high-frequency watchmaking.

In 1959, Longines reached a decisive milestone with the development of the Calibre 360, the first 5 Hz wristwatch movement, specifically designed for observatory competitions. This rectangular calibre achieved outstanding performance: in the chronometry competitions held at the Neuchâtel Observatory, it recorded a daily deviation of less than 1/10th of a second, taking first and second place in 1961, and again dominating in 1962. This mastery confirmed that high frequency was not just a technical feat, but a practical way to improve stability and rate regularity, especially against shocks, positional changes, or temperature variations.

Building on this success, Longines decided to adapt this cutting-edge technology for serial production. In 1967, the brand unveiled the Ultra-Chron, the first large-scale, high-frequency automatic wristwatch, equipped with the Calibre 431 featuring patented dry lubrication and an instantaneous jumping date. The performance was such that the brand guaranteed an accuracy of ±2 seconds per day, or one minute per month, far exceeding the requirements of traditional chronometer certifications. The following year, the Ultra-Chron Diver became one of the first high-frequency dive watches, proving that precision could go hand in hand with robustness.

This quest for chronometry helped establish Longines as a leading name in sports timekeeping, whether in alpine skiing, equestrian competitions, or other disciplines where fractions of a second are decisive.

Nearly six decades later, Longines reaffirms this legacy. Following the acclaimed return of the Ultra-Chron Diver in 2022, the brand unveiled in 2025 the Ultra-Chron Classic, a faithful re-edition of the 1967 reference 7827. This revival goes beyond simply resurrecting a heritage design: it is powered by the exclusive Calibre L836.6, introduced in 2022, featuring a silicon balance spring, enhanced magnetic resistance, and full-watch chronometer certification by TIMELAB under the ISO 3159 standard.

The Ultra-Chron Classic thus embodies the philosophy of Longines: honoring the past without renouncing contemporary advancements. It shows that a design born in the 1960s, when combined with today’s technical standards, can offer collectors and enthusiasts an authentic watchmaking experience with exemplary precision.

Revisited Vintage Design

The Ultra-Chron Classic 37 mm is a direct tribute to the elegance and refinement of the original 1967 model. Longines sought to recapture the spirit of a watch that embodied the modernity of its time, while subtly adapting it to the expectations of today’s collectors.

At first glance, the 37 mm stainless-steel case, with its slender 10.95 mm profile, impresses with its balanced proportions, very close to the historical 35 mm. This deliberate choice reflects the brand’s intent to preserve the compact and refined look of the original piece, ideal for wrists seeking comfort and understated elegance.

The charm also lies in the domed, sunray-brushed silver dial, a true signature of the Ultra-Chron. Its delicate reflections capture light with the same softness as the 1967 model and highlight the central crosshair, another hallmark graphic detail of the era.

At 6 o’clock sits the historic applied Ultra-Chron logo, finely polished and slightly raised, complemented at 12 o’clock by the iconic Longines winged hourglass emblem. This distinctive feature, reproduced exactly as on the original model, underscores the heritage character of the watch and reinforces its authenticity.

The faceted applied rhodium-polished hour markers and baton hands are filled with black lacquer — a deliberate choice faithfully echoing the vintage look, but one that omits luminescence.

The trapezoidal date window at 3 o’clock, adorned with the same typography as the historical Calibre 431, is a nod to the past and contributes to the dial’s visual harmony. The whole is protected by a box-shaped sapphire crystal, domed like the acrylic crystals of the past, but treated with a multi-layer anti-reflective coating on both sides, ensuring excellent legibility and durability.

On the reverse side, the solid screw-down caseback features the historic Ultra-Chron logo and the engraving “Chronometer officially certified,” a symbol of the chronometric excellence that has defined this model since its origins.

Water-resistant to 5 bar (50 m), the Ultra-Chron Classic 37 mm is not a professional diver’s watch, but it offers sufficient protection for everyday wear.

A true aesthetic and functional highlight, the multi-link stainless-steel bracelet reflects the retro spirit of the 1960s. Its alternating brushed and polished links subtly play with the light and extend the lines of the case harmoniously.
The 19 mm lug width, faithful to the watch’s proportions, contributes to its balanced fit.
The bracelet is equipped with a double-folding safety clasp with a micro-adjustment system, ensuring both perfect comfort on the wrist and adaptability throughout the day.

Every design detail has been carefully considered to recapture the spirit of the 1960s while ensuring the comfort and reliability of a contemporary timepiece. The Ultra-Chron Classic 37 mm is thus a faithful, elegant, and understated re-interpretation of a milestone in Longines’ watchmaking history.

High-Frequency Calibre L836.6

The heart of the Ultra-Chron Classic 37 mm beats with the exclusive Longines automatic Calibre L836.6, a direct heir to the brand’s century-long expertise in high-frequency watchmaking.

Introduced in 2022 for the re-edition of the Ultra-Chron Diver, the Calibre L836.6 perpetuates the spirit of the legendary 1967 Calibre 431 while incorporating cutting-edge innovations.
Beating at a fast pace of 5 Hz (36,000 vibrations per hour) — ten oscillations of the balance wheel each second — it ensures superior rate stability, as deviations caused by shocks, positional changes, or accelerations are corrected more rapidly than in traditional 3 Hz or 4 Hz movements.

At the core of this movement, the silicon balance spring is one of its most significant assets. Lighter and unaffected by temperature fluctuations or magnetic fields, it gives the calibre magnetic resistance ten times higher than the ISO 764 standard. This not only guarantees long-term precision but also day-to-day reliability in the face of modern environmental constraints.

The Calibre L836.6 also delivers a comfortable 52-hour power reserve, more than sufficient for alternating between watches without having to wind it frequently.

Another noteworthy distinction: unlike conventional certifications that apply only to the movement, the Ultra-Chron Classic is certified as a chronometer by TIMELAB under the ISO 3159 standard after tests performed on the fully assembled watch.
For 15 days, the watch undergoes rigorous trials: positioned in various orientations and exposed to three different temperatures (8 °C, 23 °C, and 38 °C), it must maintain exemplary precision.
This approach ensures that chronometric excellence is guaranteed not only in the laboratory but also in real-world conditions.

With this movement, the Ultra-Chron Classic 37 mm does more than honor the past: it revives the promise that made the original collection successful — certified, enduring precision worthy of a true “Ultra-Chronometer.”