Patek Philippe Split-Seconds Monopusher Chronograph with Perpetual Calendar, Ref. 5373P-001

Patek Philippe presents a new reinterpretation of its iconic Ref. 5372 Split-Seconds Monopusher Chronograph.

Especially dedicated to left-handers, the new Patek Philippe Ref. 5373P-001 features a platinum case and modern looks that emphasize its sporty and contemporary style dial. It will be produced in small series.

Patek Philippe Split-Seconds Monopusher Chronograph with Perpetual Calendar, Ref. 5373P-001
Image Credit: Patek Philippe

In 2005, Patek Philippe developed a complete series of chronograph movements with and without additional functions. All of them were designed and produced in-house.

The first among them was the manually wound caliber CHR 27-525 PS, the world’s thinnest column-wheel-controlled split-seconds chronograph movement. The caliber CHR 27-525 PS Q launched in 2010 (with the same base movement plus an extremely thin calendar module) has a height of only 7.3 mm. It is the thinnest split-seconds chronograph movement with perpetual calendar ever produced by the manufacture.

Since 2017, this exceptional caliber has been crafted in very small numbers in line with venerable watchmaking traditions. It ticks in a platinum watch with a blue sunburst dial (Ref. 5372P-001) or a rose gilt dial with a vertical satin finish (Ref. 5372P-010).

Inspired by a one-of-a-kind piece sold by Patek Philippe in 1927, a custom-made cushion-shaped split-seconds chronograph (movement No. 198 012), the manufacture has now converted the Ref. 5372 into a new version for left-handers.

The exclusive Ref. 5373P-001 combines a split-seconds chronograph with one of the most elaborate functions – the perpetual calendar which stands emblematically for the grand complications of Patek Philippe.

With a diameter of 38.3 mm, the platinum case has the same size as the Ref. 5372 but its crown (with an integrated chronograph monopusher) is at 9 o’clock and the split-seconds pusher occupies an unusual position at 8 o’clock. It preserves its timeless elegance with the polished, concave bezel that creates the perfect transition to the slightly domed sapphire-crystal back, the recessed and satin-finished case flanks, and the delicately curved strap lugs that merge with the bars almost seamlessly.

The indications (counters and apertures) of the dial are rotated by 180°: the analog date at 12 o’clock, the subsidiary seconds at 3 o’clock, the moon phases at 6 o’clock and the 60-minute counter at 9 o’clock, complemented by the aperture displays for the day of the week and the month as well as the leap year cycle at 10:30 and the day/night indicator at 1:30.

Patek Philippe has also reworked the aesthetic appeal of the dial, endowing it with a charcoal-colored aspect and a vertical satin-finish; it is ingeniously animated by a black gradation to the periphery and the snailed ebony-black subsidiary dials. The indication of the time is based on applied Arabic numerals and faceted Dauphine hour and minute hands in white gold.

The moon-phase display is extremely precise: it deviates from the actual lunar cycle by just one day every 122 years.

For crisp legibility, the three chronograph hands from the center – chronograph and split-seconds hands as well as the 60-minute counter hand at 9 o’clock – are varnished red. The three chronograph commands (Start, Stop, and Reset) are selected with the monopusher in the crown at 9 o’clock. Stopping lap times with the split-seconds hand (rattrapante) is handled with the rectangular pusher at 8 o’clock.

Patek Philippe Split-Seconds Monopusher Chronograph with Perpetual Calendar, Ref. 5373P-001
Image Credit: Patek Philippe

A sapphire-crystal display back (interchangeable with the solid-platinum back delivered with the watch) reveals the fantastic architecture of the caliber CHR 27-525 PS Q movement with its two column wheels that bear two polished caps in the typical Patek Philippe style.

The bridges, decorated with Geneva striping, are carefully chamfered and the edges are polished. A focus is also on the elegance of the form parts and the bridges à l’ancienne. Their acute internal angles can only be completed by hand, which calls for considerable dexterity and many years of experience.

The sporty looks and modern attitude of the dial also applies to the black calfskin strap with an embossed textile texture and red contrast seams. It is secured with a platinum fold-over clasp.

Patek Philippe Split-Seconds Monopusher Chronograph with Perpetual Calendar, Ref. 5373P-001
Image Credit: Patek Philippe

Like all of Patek Philippe’s platinum watches, the new Ref. 5373P-001 features a brilliant cut diamond in the caseband. As an exception for left-handers, it is set at 12 o’clock in this timepiece.

From now on, this watch is the only remaining model with the caliber CHR 27-525 PS Q movement that was formerly available in the Ref. 5372P-001 & 5372P-010; both models have been retired from the collection.

Crafted in 1925-1926 on request for a left-handed customer and sold in 1927, this split-seconds chronograph with a cushion case in 18K yellow gold (34 x 34 mm) and movement No. 198‘012 (diameter 13 lignes) stood out with its unusual arrangement of operating elements and displays.

The case and the movement were rotated by 180° with the chronograph pusher at 9 o’clock instead of 3 o’clock and the split-seconds pusher at 8 o’clock instead 2 o’clock.

The silver dial with black Brequet numerals was reconfigured to reposition the 30-minute chronograph counter from 3 to 9 o’clock and the subsidiary seconds from 9 to 3 o’clock. The uncommon shape of the chronograph and split-seconds hand with counterweights stands out as well.

Technical details

Model: Patek Philippe Ref. 5373P-001 Split-Seconds Monopusher Chronograph with Perpetual Calendar

Caliber CHR 27-525 PS Q
Manually wound mechanical movement, split-seconds chronograph with column wheel, chronograph and split-seconds hand, 60-minute counter, and subsidiary seconds. Perpetual calendar with day, month, leap-year cycle and day/night indication in apertures, analog date. Moon phases.
Diameter: 27.3 mm
Height: 7.3 mm (base movement: 5.25 mm; perpetual calendar: 2.05 mm)
Number of parts: 476
Number of jewels: 31
Power reserve: Min. 38 hours – max 48 hours (with the chronograph uncoupled)
Balance: Gyromax®
Frequency: 21,600 semi-oscillations per hour (3 Hz)
Balance spring: Breguet

Crown functions
2-position crown
– Pushed in: To wind the watch
– Pulled out: To set the time and stop the seconds hand

• Pusher in the crown at 9 o’clock to start, stop, and reset chronograph
• Pusher at 8 o’clock to start and stop the split-seconds hand

Center hour and minute hands
Sweep chronograph and split-seconds hands

Subsidiary dials
• Subsidiary seconds at 3 o’clock
• 60-minute counter at 9 o’clock
• Date at 12 o’clock

Display apertures
• Day of week at 3 o’clock
• Month at 9 o’clock
• Day/night at 1:30
• Leap-year cycle at 10:30
• Moon phases at 6 o’clock

• Day of week between 2 and 3 o’clock
• Month between 6 and 7 o’clock
• Moon phase between 4 and 5 o’clock
• Date at 6 o’clock
Delivered with correction stylus in ebony and 18K white gold

Patek Philippe Seal

950 platinum
Delivered with solid platinum back and interchangeable sapphire-crystal display back
Water-resistant to 30 meters (3 bar)
Case dimensions: Diameter: 38.3 mm
Height: 12.93 mm
Width between lugs: 20 mm

Dial in 18K gold, charcoal-colored with black gradation, vertical satin finish
Applied Arabic numerals in 18K white gold
Faceted Dauphine hour and minute hands in 18K white gold
Arrow-shaped chronograph and split-seconds hands in Pfinodal, lacquered red, counterweighted
Snailed ebony-black subsidiary dials:
– Subsidiary seconds at 3 o’clock: White-gold baton hands, lacquered white
– 60-minute hand at 9 o’clock, white-gold baton hand, lacquered red
– Date hand at 12 o’clock: White-gold baton hands, lacquered white

Black calfskin with embossed textile texture and contrasted red stitching, platinum fold-over clasp