For well over a century, Longines has been obsessed with high-frequency controlled timing systems. The company invented their first 5Hz stopwatch with flyback function, capable of measuring 1/10th of a second, in 1914, and then outdid themselves two years later, in 1916, with a 50Hz stopwatch. The apparatus, which included a balance that vibrated at 360,000 vibrations per hour, could measure time to the hundredth of a second.
Longines applied their high frequency know-how to this new form as the wristwatch gained mainstream. To make a point, the manufacturer began sending these high frequency wristwatches to third-party validators and chronometric competitions hosted by prestigious observatories such as the Observatoire de Neuchâtel and the Contrôle Officiel Suisse des Chronomètres (COSC). Needless to say, Longines received several awards.
Longines gained the courage to push the boundaries even farther, eventually challenging even electronic watches. Because high-frequency timepieces beat faster, their power reserves are depleted much faster, and the components wear out much faster. To get around this, Longines developed a dry lubrication in 1966, which, among other things, allowed for the calibre 431. This movement was able to ensure a monthly accuracy of one minute, or two seconds every day. Longines boldly titled the calibre 431-powered timepiece the Ultra-Chron since it significantly exceeds the criteria of COSC, the chronometer certifying organization.
Still in the 1960s, Longines incorporated the calibre 431 into the Ultra-Chron Diver, a 200m water-resistant dive watch. This is where we take up the linage of the reprinted Ultra-Chron Diver from 2022. The modern Ultra-Chron Diver is housed in the same cushion-shaped casing as a specific 1968 Ultra-Chron Diver, complete with a stunning red minutes hand. When it comes to the unidirectional bezel, Longines has included a sapphire inlay with Super-LumiNova to ensure that the diving bezel remains readable in low-light circumstances.
Longines designed the new calibre L836.6 in collaboration with ETA for the movement, which has a frequency of 5Hz. To demonstrate that Longines is not just blowing its own high-frequency horns, the new Ultra-Chron Diver has been chronometer-certified by TIMELAB, an independent body that is also in charge of the Poinçon de Genève mark of excellence. TIMELAB submits the timepiece to a series of tests lasting 15 days, during which the watch’s accuracy is assessed at three temperatures: 8°C, 23°C, and 38°C. TIMELAB differs from its competitors in that its accreditation is based on evaluating cased-up movements – genuine watches. COSC, on the other hand, awards certification to base movements.