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The world’s leading watchmakers establish a new state of the art for the perpetual calendar. 

“My first encounters with perpetual calendars were marked by mostly frustration,” says Stephen Forsey, a cofounder of the Swiss watchmaker Greubel Forsey. “Interacting with all the various pushers and correctors, especially on the earlier perpetual-calendar wristwatches, was a highly laborious process.”

Forsey’s exasperation is shared by many owners of these complicated timepieces, which, once properly set, can register the correct date regardless of the month, even during leap years. This remarkable feat has earned the perpetual calendar a place in the canon of classic horological complications, but a handful of top watchmakers, including Forsey, have recognized the need to modernize the mechanism, which originated in the 18th century. Their ingenious solutions for making these timepieces easier to set and read represent the most significant burst of activity yet in this particular arena of watchmaking.

Like other watchmakers, Forsey is quick to acknowledge that he is not the first to set aside the traditional design of the perpetual calendar. That credit goes to the horological visionary Ludwig Oechslin, who, while working with Ulysse Nardin in the 1990s, conceived an alternative to the traditional format. Instead of a cumbersome lever system, which reads critical calendar information from a complex cam system, Oechslin organized his concept around wheels with teeth of differing lengths that only engage one another at the appropriate time of the year. Aside from its simplicity, the great advantage of the Perpetual Ludwig, as it came to be called, was that it could be adjusted forward or backward via the crown. For the first time, the headache of single-direction pushers became a thing of the past.

Like older perpetual-calendar designs, Ulysse Nardin’s system was devised to be modular so that it could be easily attached to a base movement. This year, Ulysse Nardin has combined its perpetual calendar with one of its own calibers, making the Perpetual Manufacture ($52,500 in rose gold) one of several of the brand’s watches to include movements created entirely in-house.

The Rotonde de Cartier Astrocalendaire ($204,000), a new perpetual-calendar design from Cartier, also employs a wheel-based date-keeping mechanism, though Cartier integrates this assembly directly with the watch’s movement. The watch’s novel date indicator, which encircles its tourbillon, is constructed like an amphitheater, with the different levels displaying the current date, month, and day of the week. “We have been working on the concept of this watch for quite a long time,” says Carole Forestier-Kasapi, Cartier’s head of movement development. “The mechanical memory necessary to track the passing months resides in a structure we call the brain of the watch.” Forestier-Kasapi’s unique wheel-based system employs flexible teeth that can move in and out of place to engage or disengage the other wheels when a month shorter than 31 days necessitates a premature skip to the first of the next month. According to her, this system has much less impact on the amplitude of the balance—and therefore the accuracy of the watch—than a conventional perpetual calendar.

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