major player in the world time field, Vacheron Constantin offers a different approach with its Traditionelle World Time watch, which was presented in 2011 and displays all 37 of the different time zones into which the 24 hours are divided up. This watch did not come from nowhere. Back in 1932, Vacheron Constantin presented the first pocket watch equipped with an ‘international time mechanism’, another invention by Louis Cottier.

Between 1936 and the 1940s, numerous models succeeded one another, with dials showing 30 or 31 cities (references 3650 and 3638), or even 67 localities, including Paris summer and winter time, displayed on miniature clocks with mobile dials (1937-1938). Starting in the 1940s, Vacheron Constantin attributed the reference number 4414 to its international time model with a dial showing 41 cities and the mobile, 24-hour disc divided into day and night. Then, in 1957, Vacheron Constantin opened a new chapter in its history of world time watches with the presentation of its first wristwatch indicating international times: reference 6213, an order from an Egyptian dignitary. It would be the first of a long series.

Vacheron Constantin, Patrimony Traditionnelle Heures du Monde

Half-hour, quarter-hour…

How can you display 37 time zones in a circle of 24 hours? The Patrimony Traditionnelle World Time model displays the time on three dials: a sapphire dial with day/ night shading, a metal dial with a Lambert-projection map and a metal minute ring. On it, you can read the time in all the regions of the world simultaneously – while at the same time viewing the day/night indicator on the central world map.

Beating at a frequency of 4 Hz (28,800 vibrations an hour) and with a power reserve of around 40 hours, the 2460 WT self-winding calibre displays the hours, minutes, centre seconds and world time. All the indicators are adjusted using the crown, which greatly simplifies use of this highly technical watch.

Three concentric circles superimposed on the same ring are required to accommodate the 37 different time zones. True, legibility suffers compared with the traditional 24 zones. But for the sake of ease-of-use, all adjustments are made using the single crown. Patented and stamped with the Geneva Seal, the Calibre 2460 WT is endowed with a stop-second function for more accurate setting.