What it is
Vacheron Constantin’s technical highlight for 2019, the Traditionnelle Twin Beat Perpetual Calendar has a simple premise: Correcting a perpetual calendar that’s stopped running can be a hassle, so a watch with a sufficiently long power reserve will keep the indications up-to date even when left unworn. Here, the watch’s power reserve stretches up to an astonishing 65 days, thanks to its eponymous Twin Beat system, which uses two balance springs. Users can choose their preferred frequency with a single pusher: The “Active” mode balance is smaller, and beats at 5Hz for optimal timekeeping on the wrist. The “Standby” mode balance is larger, and oscillates at just 1.2Hz. This low frequency makes the watch prone to inaccuracies when subjected to the shocks occurring with daily use, but is fine for long periods of inactivity. It is in this latter mode that the watch can run for up to 65 days on a full wind.
How it looks
The Traditionnelle Twin Beat Perpetual Calendar looks fairly avant-garde, and doesn’t display the traditional design codes that aficionados might expect from the brand. Guilloche on the upper half of the dial and applique indexes set against a railway track chapter ring hark back to other Traditionnelle models, but the Twin Beat’s other elements are starkly modern. Note the sandblasted movement surfaces, or the frosted subdials for the calendar displays at five and seven o’clock.
How it wears
Despite its technical complexity, the watch is reasonably sized by contemporary standards, at 42mm across and 12.3mm thick. The Twin Beat system is the highlight and actuating it is a pleasure. To ensure a seamless transition between the two balances, the Twin Beat system uses an “all-or-nothing” construction similar to minute repeaters, with a corresponding snappy tactility to it.
Manual-winding movement with 65-day power reserve
42mm in white gold