Hiren Kumar Bose on why Vacheron Constantin’s Traditionnelle Twin Beat Perpetual Calendar is an outstanding timepiece
When the most talked-about watch wins an award. More importantly, the “Innovation Prize” at the 19th edition of GPHG (Grand Prix d’Horlogerie de Genève) you feel vindicated and say: I knew it would. Vacheron Constantin’s Traditionnelle Twin Beat Perpetual Calendar was the talk of the town at the SIHH (Salon International de la Haute Horlogerie ) 2019 and has now claimed the crown while competing with five others at the GPHG.
Asked to describe the watch in a sentence, I would say something like this: It’s a perpetual calendar that one can lay aside and still all calendar indications would be correct when picked up again after two months!
Mechanical watches traditionally rely on a single, spring-loaded barrel that discharges energy to its regulating organ which is good for three or four days, after which the watch runs out of power and need to be reset. Extending running time requires more barrels and a larger, bulkier-looking case but Vacheron Constantin has managed it in a case measuring just 42mm across and 12.3mm deep—the inspiration coming from an 18th-century Japanese clock. Powering its new Perpetual Calendar for a benchmark 65 days it required a movement that could switch between a conventional “high beat” (5Hz) and a “standby” mode of just 1.2Hz. Delivering on this has landed the company two patents and a watch that obviates the need for a watch-winder.
The watch comes with a normal power reserve of 4 days, however, when put in so-called “Standby Mode” and the movement switches to a lower frequency, the power reserve is jacked up for over two months. By equipping this perpetual calendar with one large mainspring, two gear trains, each with its own oscillator ticking at a different frequency, Vacheron has come up with the perfect solution to the problem most manually wound perpetual calendar encounter—of setting the calendar indications after it has been in storage for some time. Or a perpetual calendar with automatic winding with your vault not equipped with an automatic watch winder.
The power reserve indicator at the 12 o’clock position shows two aligned scales, one for the Active Mode with 4 days of power reserve and one for the Standby Mode with 65 days. On the lower half are three sub-dials, one for the months, one for the date, and in between these two is a small dial for the leap years. At 9 o’clock is an indicator for the selected mode: Active Mode with a frequency of 5Hz or Standby Mode with a frequency of 1.2Hz. The hour and minute hands feature two different finishings—one side is polished and the other grained for enhanced legibility.
The upper part of the watch’s face features sort of a half dial and the lower part of the face mainly shows the movement, plates and some gears. The semi dial is a gold plate, adorned with a very nice handmade radial guilloche and NAC treated. This is fitted within an outer rim of sapphire crystal with applied gold hour indexes. The movement’s plates, visible on the lower side of the face, are sandblasted and are subsequently NAC treated.
Interestingly, the Vacheron Constantin Traditionnelle Twin Beat Perpetual Calendar is not a limited edition piece and five pieces of the same is being offered presently.