Monochrome Watches
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Patek Philippe Annual Calendar Regulator 5235R

Unique, unusual, but never underestimated... The Regulator Dial coupled with an Annual Calendar, by Patek.

| By Rebecca Doulton | 7 min read |
Patek Philippe Annual Calendar Regulator 5235R

When it was introduced in 2011, the Annual Calendar Regulator 5235G raised some eyebrows among Patek Philippe’s more conservative collectors. Associated with elegant, 3-hand dress watches, the Calatrava suddenly appeared with a complication and a most unusual dial inspired by historic regulator clocks – a first for a Patek Philippe wristwatch. But there were more surprises, this time under the bonnet in the form of a brand new self-winding, ultra-thin movement (calibre 31260) designed specifically for this watch bristling with state-of-the-art Silinvar components and an unusual beat rate of 3.2Hz. The first 5235, which appeared in a white gold case with a silver/blue themed dial was discontinued and replaced in 2019 by this bolder rose gold model with a dark two-tone dial. Warmer, and more imposing than the colder and more technical white gold model, let’s take a look at the latest Patek Philippe Annual Calendar Regulator 5235R, an unusual marriage of an annual calendar complication and a historic regulator dial.

Patek Philippe Annual Calendar Regulator 5235R

A 20th-century horological achievement

Most of the traditional complications have been invented already long ago – think late-18th or early-19th century. However, there is one invention that many believe has been kicking around for aeons and that was actually invented in the mid-1990s: the annual calendar. A winning compromise between a complex-to-adjust, fragile and expensive perpetual calendar and a mundane date watch that needs adjusting five times a year, the annual calendar was invented and patented by Patek Philippe in 1996.

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The Patek Philippe reference 5035, the watch that, in 1996, first brought the annual calendar on the market, as the brand’s invention. Image by

The beauty of an annual calendar is that it only needs one adjustment a year, hence the name “annual”. Displaying the month, the day of the week and the exact date of months comprised of 30 or 31 days, the only adjustment takes place on March 1 to account for February’s rebellious behaviour (there are three recessed pushers in the caseband to adjust the annual calendar). The launch in 1996 of Patek’s Annual Calendar Ref. 5035 set a new benchmark in watchmaking.

Another example of Patek Philippe reference 5035 Annual Calendar – photo by Antiquorum

Unlike perpetual calendars that depend on a complex cam and a large lever, the annual calendar uses stacks of gear wheels that are easier to produce and assemble and keep costs in check. The practicality of the complication inspired other leading brands and within four years A. Lange & Söhne presented its own annual calendar complication on board the Saxonia and even Rolex developed an annual calendar for its Sky-Dweller. And not mentioning countless other brands. You can read all about the different genres of calendar watches in Xavier’s in-depth article.

Regulator Clocks

Regulator clocks, also known as pendulum clocks, were developed in England in the early 1700s. Driven by weights with a deadbeat escapement, the unprecedented accuracy of regulator clocks over other clocks converted them into master-clocks, used in observatories and clock shops to consult the time to the exact minute and second.

Patek Philippe Annual Calendar Regulator 5235R

The distinctive feature of regulators was the separation of minutes, hours and seconds. The minutes became the true protagonists of the dial read with a large sweep hand, while the hours and seconds were usually relegated to smaller sub-dials. This was possible because the three hands worked off different mechanisms. The direct inspiration for Patek Philippe 5235R was taken from a wall-mounted regulator clock that ticks inside Henry Stern’s Geneva office.

A dial with impact

The 18k rose gold case of Patek Philippe Annual Calendar Regulator 5235R measures 40.5mm and has a thickness of 10mm. A contemporary size for sure, but slim enough for a dress watch and remarkably thin if we take into account the complexity of the watch. Alternating polished surfaces and beautifully brushed flanks speak of the watch’s pedigree and the choice of rose gold ups the warmth factor no end. However, the real showstopper here is the extremely graphic two-tone dial.

Patek Philippe Annual Calendar Regulator 5235R

Unique, unusual, different from all the other Patek watches… but genuinely elegant. The 5235R is a superb creation.

An unusual dial layout for a brand like Patek (brands like Chronoswiss have made regulator dials a house feature), once you get used to the location of the functions, the information is extremely easy to read. The black railway minutes track with white numerals on the periphery underlines its status as a regulator watch and a thin long white hand extends from the centre to land on the dark area of the track and signal the minute with impeccable accuracy. The hours are relayed in a sub-dial at 12 o’clock while the small seconds appear at 6 o’clock.

Patek Philippe Annual Calendar Regulator 5235R

Patek Philippe Annual Calendar Regulator 5235R

Both sub-dials, slightly recessed from the main dial and framed by a golden ring, follow the colour scheme of the minutes track with a black snailed background and clear white markings and hands. The annual calendar functions are also relayed with simple elegance in three apertures on the dial. The day of the week at 10 o’clock, the month at 2 o’clock and the date inside the small seconds counter. Framed by a bevelled window, the background is black and the inscriptions white ensuring maximum legibility.

Patek Philippe Annual Calendar Regulator 5235R

Described by Patek as a “two-tone graphite and ebony black” dial, the vertical satin finish on the grey areas adds an almost textile dimension to the watch. The striations in the grey reveal a lighter grey reminding me of the material of a smart grey suit. Handsome and extremely masculine, the combination of warm rose gold and powerful dark tones will not go by unobserved. And in keeping with the highly graphic and instrument nature of a regulator, there are no superfluous inscriptions on the dial – even the ‘Patek Philippe Genève’ is discreetly engraved on the dial.

Tailor-made calibre 31-260 REG QA

While the dial might hark back to historic regulator clocks, the movement is state-of-the-art packed with all Patek’s breakthrough Silinvar (silicon) goodies to ensure the regulator performs its task with maximum precision. Instead of fiddling with its omnipresent calibre 240, Patek created the entirely new self-winding calibre 31-260 REG QA for its hybrid regulator/annual calendar. Still wound by a 22k gold off-centred micro-rotor but with a new architecture, the basic movement is only 0.07mm thicker than calibre 240 developed in 1977; it is also the first new movement designed to accommodate Silinvar components.

Patek Philippe Annual Calendar Regulator 5235R

The advantages of Silinvar over metal are threefold: it is anti-magnetic; it is not machined like metal components but chemically etched to molecular proportions, which are far more exacting; and its extreme hardness and smooth surfaces eliminate the need for oil between the pallet and escape wheel. While the classic self-winding calibre 240 beats at a rate of 21,600 semi-oscillations per hour, the frequency of the new movement was increased by nearly 10% to 23,040vph, equivalent to 3.2Hz, and at the same time, its power reserve was increased to 48 hours and its rate accuracy to -3/+2 seconds per day. Certified by the Patek Philippe Seal, the movement features Haute Horlogerie finishes including Côtes de Genève stripes and perlage.


The one and only model with a regulator-style display in the brand’s line-up, the Patek Philippe Annual Calendar Regulator 5235R is not your standard Patek fare and might not even get recognised as a Patek! Which is precisely why I love this watch; it’s different, it’s dynamic and it’s kind of quirky. The bold black and grey colour scheme is powerful and elegant and the white markings make it extremely legible indeed. Coupled with a practical and hassle-free annual calendar, this slightly unorthodox watch will probably appeal to more mature Patek collectors. And the case itself, with these sharp lugs, is simply superb.

Patek Philippe Annual Calendar Regulator 5235R

Availability and price

The Patek Philippe Annual Calendar Regulator 5235R (exact reference being 5235/50R) comes with a matte black alligator strap and rose gold prong buckle. The retail price of this model is EUR 47,410. For more information, please consult

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