While Patek Philippe’s fall novelties include some hotly anticipated updates to its sports watch saga, it also encompasses a grand complication carefully conceived in a sporty and contemporary manner – the Perpetual Calendar Rattrapante Chronograph Ref. 5373P.

Slated to replace the outgoing Perpetual Calendar Monopusher Rattrapante Chronograph ref. 5372P/001 in blue and ref. 5372P/010 with a salmon dial launched in 2017, the new ref. 5373P is the first contemporary, regular-production (albeit in a small series) Patek Philippe watch with a left-handed or “destro” crown. Like its predecessor, it combines two of Patek Philippe’s most prized complications – a split seconds chronograph and a perpetual calendar, making it the most complicated “destro” watch on the market.

The left-handed watch format, however, is not without precedent in the history of Patek Philippe. In 1927, the manufacture created a unique, left-handed single-button split-seconds chronograph wristwatch with a cushion-shaped gold case for its American retailer, Grogan & Co., one of Pittsburgh’s most prominent jewellers of the 20th century. The watch has since surfaced in 2006, selling for a whopping CHF 2,372,000 at Christie’s.

Cased in platinum, the new reference has the exact same dimensions as the ref. 5372P, measuring 38.3mm in diameter and a slim 12.93 high as it houses the same CHR 27-525 PS Q, which is made up of the magnificently slim split-seconds chronograph movement that first debuted in the hallowed ref. 5959 in 2005 and a thin perpetual calendar module built atop.

The case remains identical to its predecessor in form and finish, featuring a polished, concave bezel contrasted by a pronounced satin-brushed recess along its case flanks. It features slender, elegantly curved lugs with a distinctive press-fitted platinum caps at their ends.

As the movement had to be inverted to relocate the crown to the nine o’clock position, the position of the pushers as well as the layout of the counters and calendar discs are rotated by 180 degrees from their usual positions. The split seconds pusher is now located at eight o’clock while the analogue date is located at 12 o’clock, the running seconds at three o’clock, the moon phases at six o’clock and the 60-minute totalizer at nine o’clock, with the aperture displays for the leap year and day-and-night indicator are relocated to the top half of the dial.

Beyond the change in configuration, the watch is also an exercise in contemporary aesthetics. The dial has a vertical satin finish, with a charcoal grey cast that goes from a slate grey at the centre of the dial to ebony black at the periphery. The applied Arabic numerals and faceted Dauphine hour hands are in white gold while the chronograph seconds hands as well as the 60-minute totalizer hand are varnished red for absolute contrast and dynamism. This distinctive colourway continues onto the strap made of black calfskin with an embossed texture and red stitches.

Visible through its sapphire case back is the tiny but tremendous CHR 27-525 PS Q. The split seconds cal. CHR 27-525 PS was Patek’s first in-house chronograph movement and one of the most elaborate and classically beautiful chronograph movements ever created by any brand, period. At the time of its launch in 2005, the CHR 27-525 PS movement was the slimmest split-seconds chronograph movement on the market, standing at just 5.25 mm high. It was by inspired by an old Victorin Piguet ebauche and thus was traditionally and aesthetically constructed with many exceptionally refined details. Notably, the chronograph drive wheel is supported by its own finger bridge, echoing the flow of the bridges supporting the base gear train, while the clutch lever has an incredibly slim and sinuous shape. Notably, the clutch lever is fully supported; it pivots over the drive wheel and clutch wheel, providing greater stability and consistency of engagement. Equally beautiful are the remarkably slim steel springs for the split-seconds mechanism.

In the CHR 27-525 PS Q, it is topped by a perpetual calendar module that relies on a 12-month cam with a pivoting satellite. As a general rule of thumb – all Patek Philippe’s perpetual calendars with triple calendar counters employ a 48-month cam while other configurations utilize a 12-month cam with a satellite system. While there is also third possible execution of a calendar program wheel, which is a single 12-month cam that works in conjunction with a separate leap year cam, the benefit of the two approaches employed by Patek is that the leap year is already encoded in the month cam, freeing up space.

The 12-month cam makes a full rotation in a year with small satellite wheel to manage the leap month of February. The satellite makes a 90° rotation once a year, completing a full rotation in four years. The movement measures just 7.3 mm high in total.

All told, the appeal of the watch ultimately lies in its delicious juxtaposition of a modern and sporty dial design and one of the most beautifully constructed traditional chronograph movements ever created.

Tech Specs

Patek Philippe Perpetual Calendar Monopusher Rattrapante Ref. 5373P “Destro”

Movement: Caliber CHR 27-525 PS Q, manual-winding, power reserve min. 38 hours – max 48 hours
Functions: Split-second Monopusher chronograph, day, month, leap year and day/night indications in apertures, date, moon phase, small seconds
Case: Platinum, 38.3 x 12.93mm, water-resistant to 30M
Strap: Black calfskin, embossed with fabric pattern, fold-over clasp