Introducing the High-frequency Longines Ultra-ChronBy Jeremiah Chan
The Low Down
To the casual observer, the Longines Ultra-Chron may seem like a deep cut from Longines’ impressive and wide-ranging back catalogue of dress watches, military watches and chronographs. It was initially created in 1966, a few short years before the Swiss watch industry would face stiff competition in the form of quartz watches, cutting short its time in the market to a mere six years. However, it remains highly collectable and popular with collectors and enthusiasts. Its place in the history of Longines’ storied pursuit of chronometry cannot be overstated.
Two years after the first Ultra-Chron was launched, Longines would fit its highly accurate, high-frequency caliber 431 into the sporty profile of the reference 7970 – creating the world’s first high-frequency diving watch. The caliber 431 was guaranteed to an accuracy of one minute a month, or two seconds per day, far exceeding the 10-second deviation certified by COSC. Tritium was used to provide legibility to the indexes, hands and even the triangle on the bezel at 12 o’clock.
The new Longines Ultra-Chron revives the spirit of the original by being true to its general cushion-shaped, short lug form, but upsizing the original’s 41mm diameter to a 43mm case in stainless steel and a reasonable height of 13.6mm. With the addition of a screw-down crown and caseback, water resistance has been improved from 200m to 300m. For the uni-directional rotating dive bezel, scratch-resistant sapphire has replaced brittle bakelite and is now even more legible with luminous accents at the quarters.
The sapphire box crystal has been treated with multiple layers of anti-reflective coating, providing an undistorted view of the updated black dial, which has a grainy texture that looks like wet sand — a perfect backdrop for the flat white minute track and text. The red minute hand has been retained from the original, albeit painted with even more lume, making it impossible to miss when timing decompression stops.
Replacing the groundbreaking caliber 431 is the current high-frequency, self-winding caliber L836.6, with a silicon hairspring that is resistant to corrosion and brushes off temperature variations and magnetic fields without skipping a beat. It beats at 10Hz or 36,000 vibrations per hour. Those thousands of vibrations are energy-hungry, something that usually translates to a shorter power reserve. Longines has managed to squeeze 52 hours out of one barrel, which is decent. To test the robustness of the L836.6, Longines has turned to another independent testing laboratory based in Geneva called TIMELAB.
Unlike COSC, TIMELAB certifies completed, cased watches and not just the movements themselves. The lab runs through a range of tests over a period of 15 days before it can be certified by TIMELAB to have met the “Observatoire Chronométrique+” standard, or as Longines simply calls it, an “ultra-chronometer”. This designation takes pride of place on the caseback, inscribed above every other marking.
With its Heritage collection of watches, Longines has been universally praised for its faithful recreations of past icons. And rightly so. Fans love them for all the retro look and feel, and none of the vintage headaches. While the new Ultra-Chron does not seem to be part of the Heritage Collection, it deserves its time in the sun and is yet another example of the sort of faithful recreation that the brand does so well, from the case proportions to the dial details. The main difference is the removal of the date window that stays perfectly true to the tool watch aesthetic. It is likely that the Ultra-Chron will be a standalone novelty and one for the Longines nerds out there, seeing that the Legend Diver is the flagship heritage dive watch.
Movement: Hi-frequency, self-winding caliber L836.6 with silicon hairspring; 52-hour power reserve
Functions: Hours, minutes, central seconds
Case: 43.00 x 13.60 mm; stainless steel; uni-directional rotating bezel with sapphire insert and Super-LumiNova accents
Dial: Black-grained; Four applied silver indexes with Super-LumiNova underneath
Strap: Stainless steel bracelet with double safety folding clasp or brown leather strap with pin buckle; additional black NATO strap made of recycled material