No other watch brand can stake claim to the kind of legitimacy and expertise that Patek Philippe has in the creation of calendar watches. The venerable Geneva brand famously gave the world its first wristwatch with a perpetual calendar in 1925 when it unveiled the unique piece dubbed Ref. 97’975. From simple perpetual calendars to those that combine this high complication with others such as chronographs (Ref. 2499, anyone?), to the now-ubiquitous annual calendar watch it invented in 1996, Patek is at the top of its game when it presents a new calendar watch. 

The 40 mm steel case is only 11.18 mm thick

And as recently as 2013 it continued innovating, developing an instantaneous day-of- week and date display in its Ref. 5200 Gondolo “8 Days” watch. At Baselworld 2019, Patek Philippe revealed its latest contribution to the category, the Ref. 5212A-001 Calatrava Weekly Calendar, a wristwatch that features a new in-house caliber and also happens to be the first stainless steel piece in the mainstream Calatrava collection.

The 40-mm steel case of the Ref. 5212A-001 Calatrava Weekly Calendar represents a rare use of the non-precious metal at Patek Philippe and measures a svelte 11.18 mm thick. The case shape, with its bezel extending over the two-tiered, lightly curving lugs, is inspired by that of a unique historical piece, Ref. 2512, made in 1955 and currently kept  at the Patek Philippe Museum in Geneva. (Note that the new model’s reference number is a remix of the original’s numerals.) Remember the Ref. 5320G from 2017 also had a similar stamped case with stepped lugs.

The typography is based on the handwriting of a Patek designer

The silvery opaline dial has an unconventional layout, with five center-mounted hands – hours and minutes indicated on blackened white-gold baton indices by Dauphine hands also in blackened white gold; seconds tracked by a slender counterbalanced hand; the day of the week displayed by a hammer-tipped hand on a circular scale in the dial’s middle; and the number of both the month and the week pointed to by another similarly designed hand on two concentric scales at the periphery of the dial. 

The date appears in an aperture at 3 o’clock. In addition to this rare combination of calendar functions (in recent years, only Oris and Blancpain have released a notable calendar watch with a week indication) the dial boasts a unique style of typography created explicitly for this watch, based on the handwriting of one of its designers.

The stepped lugs are a vestige of the Art-Deco influence

Using its existing self-winding Caliber 324 as a base, Patek Philippe developed an entirely new module for these calendar functions — just 1.52 mm thick and containing 92 additional parts — resulting in the new Caliber 26-330.  Its technical innovations include a seven-point star on the hour wheel in the center of the movement to control the day-of-week display, and a second seven-point star, connected to a lever, with an extended Sunday tip, to drive the 53-tooth week wheel. 

The calendar displays advance semi-instantaneously in discrete steps to avoid energy consumption peaks. Two push-pieces recessed into the case flank allow for quick corrections of the weekday and week-number displays, while pulling the crown out to its second position corrects the date. Thanks to a fail-safe design, the user can perform these corrections at any time of day or night without damaging the movement. 

The movement was custom-made for this timepiece

Pursuant to the international ISO 8601 standard, Patek Philippe chose Monday as the first day of the week rather than Sunday, — a more common system in Europe — and the first week of the year is the week that includes the January 4. The 53-graduation scale considers years with an extra week, which is in fact the case every 5 to 6 years, including the next one in 2020. Caliber 26-330 is comprised of 34 total components, including a 21K gold central rotor and 50 jewels, and stores a maximum power reserve of 45 hours.

The Ref. 5212A-001 Patek Philippe Calatrava Weekly Calendar comes on a light brown stitched calfskin strap that attaches to the wrist with a steel pronged buckle. It will be priced at CHF29,500.