Patek Philippe has long been recognised as the premier Swiss watchmaker.

Since its founding in 1851, the maison has continually reinvented mechanisms and pushed the boundaries of watchmaking, all while retaining a pure manufacture status (with most, if not all, its components built in-house) and using largely traditional processes. Its name has transcended just timepieces and is synonymous with the highest of high-end luxury. When it comes to the brand’s contributions to the art of horology, many complications have benefitted from Patek Philippe’s expertise. It popularised split-second chronographs, minute repeaters (that we’ve covered here) as well as the perpetual calendar complication.

There are many brands that are known for their mastery of different complications and for Patek Philippe, its reputation for mastering both the ins and outs of the minute repeater and perpetual calendar complications is considered a fact. Last month, we wrote a brief story on the brand’s legacy in perpetual calendars after attending its Memory of the Future presentation, an in-depth look at the history of the brand with the perpetual calendar.

Here are some more learning points about Patek Philippe and the art of perpetual calendars.

How the Perpetual Calendar Works

At its heart, the perpetual calendar is “simply” a watch programmed to take into account the future.

In a simple calendar, a user will have to adjust the watch’s date at the end of every month. In an annual calendar, a user will only have to adjust the date at the end of February. For a perpetual calendar, every varying month is accounted for till the year 2100. Every perpetual calendar mechanism is dependent on a main lever (or multiple lever) that sits right down the middle of calibre, connected to wheels for every day, date, month, year indication. With the passing of any unit of time, it factors into the movement. Sixty seconds to a minute, 60 minutes to an hour and 24 hours to a day. When the day passes, the main lever feeds information to other wheels and helps to advance other functions that are connected such as the date as well as the month.

There are two different variations of the perpetual calendar mechanism – the perpetual calendar with a 48-month cam and the perpetual calendar with a 12-month cam. As a rule for Patek Philippe, all its tri-compax (or triple counter) dial layout perpetual calendars use 48-month cams while other configurations use 12-months. The 48-month cam turns once every four years, with several notches that allows a systematic “reading” of how long a month should take. A 12-month cam turns once a year and in turn, indicates to a leap year wheel through the main lever that a year has passed.

Below is an example of how the months work in Patek Philippe’s Calibre 324S Q (the movement in the brand’s new Ref. 5230G that we covered in last week’s story)

It’s just one example of how interconnected the module is, but a good show of how many parts are needed to build a perpetual calendar. On top of that, each part is meticulously designed with long term usage in mind and an extreme precision is needed to ensure that no parts are damaged with repeated use.

Different Styles of Perpetual Calendars

While most assume that perpetual calendars (because of the inherent amount of components on the inside) should look complicated as well, Patek Philippe begs to differ. The brand is known for its clean and clear dial layouts for perpetual calendars, often opting for a mix of both apertures as well as retrograde date indicators to keep it simple. Here are some examples of Patek’s different layouts.

Triple in line: Month / Day / Date

An old vintage pocket watch that shows off the mighty uncommon triple-in-line. This reference was last auctioned off at a Christie’s event.

Twin in line: Day / Month

The Ref. 5320G is this year’s example of how clean a perpetual calendar dial can be. The expansive lacquer dial makes it easy to read the time, without sacrificing any of the functions. This configuration is used for a very symmetrical look on the pieces and tends to add a more “modern” touch to the watch.

Star shape (with retrograde date indicator):

Patek Philippe’s 5496P-015 sees a silvery, vertical satin-finished dial contrasted against gold applied hour markers with the retrograde date display front and centre.

Circular arc: 

The Ref. 5208P-001 holds a number of complications including a minute repeater, a monopusher chronograph and instantaneous perpetual calendar with aperture displays.

Tri-compax

A perhaps slightly more complicated way of looking at the dial, as on the 5140P-017 above.

The Importance of Correction

Apart from just building a perpetual calendar, Patek Philippe needed to take into account the fact that most owners may not be able to constantly keep their watches wound. If a perpetual calendar loses power and its date is then not adjusted, it would need to be manually adjusted. There are plenty of rules when it comes to adjusting perpetual calendars (they are after all, one of the most fragile modules in complications) and it’s often a hassle. As such, most brands build correctors on the case side for easy adjustments.

Here’s a look at Patek Philippe’s in action.

And if you’re interested, here’s a timeline of Patek Philippe’s most important perpetual calendars.

written by.

Subscribe to the magazine

Subscribe Now