Feature: Perpetual Calendars

Thanks to the Romans, Pope Gregory XIII, Jesus and of course the orbit of our home, Earth, we have a calendar system that is as concise and efficient as the English language itself. I can imagine that early watchmakers loathed the fripperies of our months, years and leap years when devising methods of recording and displaying the path of our journey through space, but thankfully they persisted in their endeavours, giving us today what we call the perpetual calendar. And despite the complexity of microchips and atomic clocks, we can still enjoy the hard work of previous generations in devising what just might be the most impressive complication ever to sit inside a watch.

As with all systems that get tweaked as more is learned and priorities change, the calendar is not now how it has always been. There isn’t simply one calendar system in use today, even, there are many, including the Islamic Hijri calendar, the Hindu calendar and the Hebrew calendar; some use the path of the moon instead of the sun.

This Breitling Chrono-Matic QP is able, as its complex display suggests, to do more than ‘simply’ display an accurate perpetual calendar. As well as adding a leap year indicator, seasonal indicator, twenty-four–hour indicator and moonphase, it also has a chronograph—an impressive collection of functions even for a case as large as this. The Chrono-Matic has been a big watch since its launch in 1969, and things are no different here, the rose gold case spanning a healthy 49mm across.

Surprisingly, the calibre 29 derives its mechanicals from ETA’s 2892-A2, with chronograph and perpetual calendar modules added for the extra functionality. It’s probably just as well that the case is quite as big as it is, because the movement within is not the most compact, and with almost 500 parts, it was never going to be. Yet the detail on the bronze sunburst dial and the deep pink of the rose gold case somehow work well with the purposeful and angular design of the watch. The original Chrono-Matic was, after all, made that big to enable the fitment of the world’s first automatic chronograph movement.

Watch Spec | Breitling Chrono-Matic QP R29360

Case: Rose gold Dimensions: 49mm dia, 14.7mm thick Crystal: Anti-reflective coated synthetic sapphire Water Resistance: 30m Movement: Calibre 29, based on ETA 2892-A2, automatic Frequency: 28,800 vph Power reserve: 42 hours Strap: Leather Functions: Time, perpetual calendar, chronograph, calculator bezel

In the west it’s the Gregorian calendar that’s favoured, its roots found in the Julian calendar introduced by Julius Caesar. Pope Gregory XIII’s introduction of a skipped leap day every four hundred years, intended to keep Easter in line with the Spring Equinox, not only corrects the inaccuracy of the Julian calendar but also became something of a sticking point for watchmakers.

This is a problem that won’t affect the Breitling so much as it will the IWC, because the IWC has an additional (and mightily impressive) function: a four-digit year indicator. Nestled in the bottom left of the dial, this unassuming little device is the first of two standout features for the IWC. The watch uses a clever program wheel that accounts for days, months, years and leap years, but not for Pope Gregory’s missing day, for which it will need an in-house adjustment.

The second standout feature here is the crown, which serves as the only device to advance the time. Most perpetual calendars (and all the others here) have hidden pushers, but using a design that can be traced back to Kurt Klaus’ 1985 IWC Da Vinci, the calibre 51614 here needs nothing more than a twist of the wrist to set. But beware: advance the calendar too far and you’ll have to wait to catch up—there’s no reverse gear on this thing! This clever mechanism can in part explain the depth of this watch; at 15.5mm crystal to caseback, it’s the thickest here.

Watch Spec | IWC Portuguese Perpetual Calendar IW502119

Case: Rose gold Dimensions: 44.2mm dia, 15.5mm thick Crystal: Anti-reflective coated synthetic sapphire Water Resistance: 30m Movement: Calibre 51614, automatic Frequency: 21,600 vph Power reserve: 42 hours Strap: Rubber Functions: Time, crown-operated perpetual calendar

Aside from the once-every-four-hundred-years problem the Gregorian calendar presents, the perpetual calendar mechanism is incredibly accurate. The more astute of you may have noticed the similarity between the layout of Jaeger-LeCoultre’s calibre 876SQ and IWC’s 51614, and that’s because they share a common ancestor, that game-changing Kurt Klaus Da Vinci. Since then, Jaeger-LeCoultre have taken the concept in a radically different direction, ditching the crown-only adjustment and adding an eight-day power reserve in lieu of a rotor weight.

It doesn’t take much pointing out to highlight the Jaeger-LeCoultre’s crowning jewel, its skeletonised movement. Visible front and back, it does away with the readability of a traditional perpetual calendar in favour of appealing to the art lover and engineering enthusiast whose real desire is to understand the how, what and why behind this reverent complication. Through the front can be seen the analogue ‘brain’ that grounds the calendar’s place in time, the program wheel.

That’s the engineering; there was a mention of art, too. The underside of the watch presents a hand-skeletonised, hand-polished base plate, formed in the likeness of a globe, with each line of latitude and longitude intersecting with a jewelled pivot or hand-polished screw, plus a generous view of the twin barrels providing the mammoth eight days’ power. The same planetary design can be seen at the front, too, hiding among the hands and sub-dials fighting for presence among the stunning backdrop of the 876SQ itself.

Watch Spec | Jaeger-LeCoultre Master Perpetual Q16164SQ

Case: Platinum Dimensions: 41.5mm dia, 11.8mm thick Crystal: Anti-reflective coated synthetic sapphire Water Resistance: 50m Movement: Calibre 876SQ, manual Frequency: 28,800 vph Power reserve: 8 days Strap: Leather Functions: Time, perpetual calendar, eight-day power reserve

The first mechanical perpetual calendar watch was of the pocket variety, a complicated Breguet piece made for Marie Antoinette; the first perpetual calendar wristwatch was also from Breguet, made in 1929. Bridging the gap was a 1925 Patek Philippe wristwatch that used a perpetual calendar movement transplanted from a one-off ladies’ pendant watch. Such is the difficulty in making a perpetual calendar movement that even the greats avoided it for as long as possible while they scratched their heads trying to work out how to fit them into the tiny wristwatches of the time.

No such issue for the Germans, however, this 38.5mm diameter A. Lange & Söhne positively diminutive in present company. The 10.2mm thickness is also class-leading, and that’s despite maintaining automatic winding and introducing a big date display to the mix as well. The secret’s in the micro rotor, and although the reduced space means a limited power reserve of forty-six hours, consistent wear will see this watch without need of a manual top-up. Complimenting the 21K gold micro rotor is a German silver base plate, engraved balance cock and three-quarter layout traditional in German watch design.

It’s a beautifully proportioned watch, probably the most elegant here, and it goes to show just how different watches of this segment can really be. All four perpetual calendars featured make up only a small portion of the total, and yet each one shares a distinct personality unchallenged by the others. As for picking a favourite, well—that’s a nice problem to have.

Watch Spec | A Lange & Söhne Langematik Perpetual 310.032

Case: Rose gold Dimensions: 38.5mm dia, 10.2mm thick Crystal: Anti-reflective coated synthetic sapphire Water Resistance: 50m Movement: Calibre L922.1, automatic Frequency: 21,600 vph Power reserve: 46 hours Strap: Leather Functions: Time, perpetual calendar, big date