Monochrome Watches
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The Patek Philippe In-line Perpetual Calendar 5236P

A totally new perpetual calendar with an innovative patented one-line display

| By Brice Goulard | 5 min read |
Patek Philippe In-line Perpetual Calendar 5236P-001

Patek Philippe is known for being one of the best manufacturers of calendar watches. Whether it is the annual calendar – one of its inventions – or the perpetual calendar, alone or combined with other complications, the brand is clearly in its comfort zone. This year, as part of the Watches & Wonders 2021 collection, the brand unveils a new, ultra-clean perpetual calendar watch that displays the day, the date and the month on a single line in an elongated aperture beneath 12 o’clock. To achieve this, Patek is also releasing a new movement, for its In-line Perpetual Calendar 5236P.

There are multiple perpetual calendar watches at Patek Philippe, using a classic layout with 3 sub-dials – with the self-winding ultra-thin calibre 240 Q movement, such as the Ref. 5327 – or retrograde date indication, and even a succession of windows on an arch between 10 and 2 o’clock on the dial… For 2021, the brand adds a new face to its collection of perpetual calendar watches, where all the crucial indications are displayed in a single, uninterrupted line of text, resulting in a highly intuitive reading of the calendar function. A total of 4, non-overlapping discs are required, as well as a whole new movement with 3 patents.

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Patek Philippe In-line Perpetual Calendar 5236P-001

The “panoramic” in-line display of the Perpetual Calendar 5236P is rarely seen in modern watchmaking. It isn’t entirely unprecedented at Patek Philippe either, as the brand had already crafted pocket watches with an in-line calendar display for the American market. Yet, it is a first for a Patek wristwatch. The main advantage of this display, in addition to bringing a very clean and uncluttered dial, is to offer an intuitive view of the calendar indication, with a reading that feels natural – at least, for most of the world – with day of the week, date on two discs, and month – like here, SAT(urday) – 18 – MAR(ch).

Patek Philippe In-line Perpetual Calendar 5236P-001

To ensure this display, the watchmakers at Patek were required to design a system with two date disks – one for the tens and one for the units. So the calendar display consists of four disks, one for the day, two for the date, and one for the month – all four perfectly embedded in the same plane. A date displayed by a single disc would have been too small and less easily legible.

The most innovative aspect of the In-line Perpetual Calendar 5236P is the display with four rotating disks, assuring optimized legibility and minimal energy consumption. As explained by the brand, “this mechanism alone required 118 additional parts in comparison with a conventional perpetual calendar display, including several bridges and wheels with jewel bearings that reduce energy consumption, especially of the two date disks. To keep all the indications on one plane without any overlap, Patek Philippe’s engineers developed a display system composed of two coplanar double ball bearings for which a patent application has been filed. The dependable date display and the perfect synchrony of the two date disks are optimized with an “anti-double-jump” feature for the units disk to prevent disk bounce in the event of a jolt or when a date correction is being performed (second patent application)


To create this new In-line Perpetual Calendar 5236P, the brand has developed a new movement, on the grounds of the calibre 31-260 REG QA that was originally launched in 2011 with the Ref. 5235 Annual Calendar Regulator. While retaining the diameter and height of the basic movement (31.74 x 2.60 mm, hence the designation 31-260), the movement has been redesigned with the implementation of a small seconds indicator at 6 o’clock, and of course on top the perpetual calendar mechanism with it in-line display. For instance, the torque of the spring barrel was increased by 20% and the winding power boosted with a platinum mini-rotor that has more mass than 22k gold that is normally used for Patek Philippe mini-rotors. Also, one of the specificities of the movement found in the ref. 5235 was its unusual 3.2Hz frequency, which has been increased here at 4Hz for better rate stability.

Patek Philippe In-line Perpetual Calendar 5236P-001

Viewed through the caseback, the movement is elegant and more curved and opened than other calibres by Patek. Specifically, it comes with finger bridges for the great train, a nice touch. Finishing is, as expected, elegant and refined. The movement features classic elements, such as the Gyromax balance and Spiromax balance spring.


Talking about the watch itself, the Patek Philippe In-line Perpetual Calendar 5236P is an elegant and modernity designed piece, housed in a 41.3mm 950 platinum case, with 11.07mm height. Sharp and slender, the lugs are paired with a chamfered bezel, resulting in a clean and discreetly contemporary piece. The case is entirely polished, with the case flank featuring a small diamond at 6 o’clock – a classic feature of most platinum Pateks. As for the dial, the in-line perpetual calendar brings a clean layout, where most of the indications are placed at 6 o’clock, with the small second and moonphase subdial flanked by a leap year and day/night indication.

Patek Philippe In-line Perpetual Calendar 5236P-001

The dial of this Perpetual Calendar 5236P is executed in a now-classic dark blue colour with a straight brushed surface, and a black-gradient effect with the periphery of the dial darker than the centre. Time is read thanks to fine and faceted hour markers and baton hands in white gold. A railroad minute track on the periphery brings a slightly technical look. A navy blue alligator strap with a platinum fold-over clasp rounds out the look of this new QP.

The Patek Philippe In-line Perpetual Calendar 5236P is launched as part of the permanent collection and will be priced at EUR 113,200. More details at

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