Few complications boast the same romanticism and functionality as the perpetual calendar does. Watches with a calendar function require constant adjustment to ensure the correct date is shown, and watches will usually reset after completing 31 24-hour cycles — a full month. What that doesn’t take into account, however, is that the concept of time as we’ve created it isn’t as simple as that; we can’t just ignore the irregular number of days per month, much less the leap years.
To counter the inconsistencies of time, watchmakers set about to develop more advanced complications, which track the calendars with higher accuracy and without the need for monthly adjustments. There’s the annual calendar, which adjusts the date displayed based on 30- and 31-day months automatically, but it requires the manual setting of the date once a year, at the end of February.
So the horologists got back to work and the result was the perpetual calendar. Like its name suggests, the complication has a mechanical memory programmed for a very long time — it will indicate the correct date for a century according to the Gregorian calendar, taking into account the leap years without requiring manual correction. The only exception is when the secular year is divisible by 400. This means that three century years out of four will not be a leap year, so the proud owner(s) of a perpetual calendar watch would still be inclined to correct the date three times over the five centuries on 1 March.
With one of the most classical complications ever created, perpetual calendar watches have enamoured even the most discerning of powerhouses and aficionados. Here are 5 that you can start looking into owning now.
Following the phenomenal success of its iconic white gold and yellow gold counterpart, Patek Philippe has now released the self-winding, ultra-thin perpetual calendar model in a rose gold case. Within the cushion-shaped case is a velvety, silvery-white dial with applied Breguet numerals that provide legibility over the finesse and quiet sophistication of this well-loved Art Deco-inspired perpetual.
Serious complications shouldn’t get in your way of serious bling. If you’re a fan of both, Piaget Emperador is a 46.5mm watch made just for you. Besides the 60 baguette-cut diamonds and 386 brilliant-cut diamonds set on the 18k white gold case, there are also 263 brilliant-cut diamonds on the dial. The Manufacture Piaget 856P ultra-thin self-winding mechanical Perpetual Calendar movement is at the cusp of this watch, and features retrograde day and date display with a dual time zone indicator.
Set within a 44m pink-gold case is the wonderfully complicated Vacheron Constantin calibre 2253, a manually-wound mechanical movement that’s part of its 14 Day Tourbillon movement collection. Besides the eye-catching tourbillon-style regulation system at the six o’clock position, the movement also has a perpetual calendar, and the leap year is indicated on a small subdial of the watch (next to the month), in addition to the date and day of the week.
Inarguably one of the stars of SIHH this year, the matte black ceramic Royal Oak Perpetual Calendar gets a new tapisserie dial in a unique dark blue “Skylight” colour for charity auction Only Watch 2017, inspired by the fleeting few minutes before sunset. This inspiration carries on to the moon phase, which is noticeably more orange than that of its predecessor, giving it a warm, romantic vibe. On its back, a skeletonised rotor emphasises the weighty automatic calibre 5134, which powers the perpetual calendar feature as seen within the same subdial as the month indicator.
Glashütte translates the high efficiency and engineering prowess that the Germans have come to be known for to its iteration of a perpetual calendar timepiece. Taking legibility into great consideration, the dial is kept clean and functional with all the calendar information neatly displayed in simple and clear windows, with contrasting blue hands that stand out against the silver-grained dials. The moon in the moon phase indicator matches the case material, which can vary between red gold or white gold. Inside, the calibre 36 is a workhorse movement that runs with a power reserve of 100 hours at a healthy 4Hz.