A great classic Patek Philippe
The perpetual calendar chronograph occupies a special place in the Patek Philippe grand watchmaking tradition. In 1941, the legendary Reference 1518 united a perpetual calendar with a chronograph in a wristwatch for the first time. Ever since, these timepieces have featured among the Manufacture’s most sought-after Grand Complication wristwatches. As from 2011, this great classic has been available with the caliber CH 29-535 PS Q movement, designed and crafted entirely in the Manufacture’s own workshops (Reference 5270).
Making its global debut on the occasion of the WATCH ART™ Grand Exhibition - Milan 2026, the new Reference 5978P-010 now reinterprets this combination of functions by uniting, for the first time, the manually wound chronograph movement CH 29-535 with an instantaneous perpetual calendar offering optimal legibility with its three apertures, for the day, the date and the month, arranged along an arc.
The complexity of an instantaneous perpetual calendar with aperture displays
A triumph of technical prowess, the Patek Philippe instantaneous perpetual calendar houses the exclusive mechanism based on two patents and presented in 2008 in the Grand Complication Reference 5207, and taken up again in 2011 in the triple complication Reference 5208 and in 2023 in the quadruple complication Reference 5308. It ensures the jump of the different indications in 30 milliseconds in the four apertures, including with a residual power reserve of ten hours. The simultaneous and instantaneous forward movement of the day, date, month and leap-year indications constitutes an additional challenge, especially since, to ensure optimal legibility, they are displayed on four disks whose mass is considerably greater than that of the hands. Contrary to progressive-drive mechanisms, the instantaneous date jump requires accumulating energy over several hours and then releasing it in a fraction of a second to drive the disks rapidly and precisely. A large lever with 15 parts, some of them mobile, ensures an instantaneous jump of all the displays (first patent). A construction with two complementary jumper- springs acting in opposite directions (second patent) guarantees that the energy expended for each change remains constant despite the differences in the displacement angles of the jump of one day at the end of months of 31 days compared with the jump of four days at the end of the month of February in common years. This system makes it possible to avoid incomplete jumps caused by insufficient power and indications that jump too far owing to excess energy.
The nobility of a manually wound chronograph
Based on the architecture of the caliber CH 29-535, unveiled in 2009, the chronograph function stands out by the elegance and air of breeding of a mechanism boasting 6 patented innovations optimizing its performance and reliability. True to the grand tradition of manually wound chronographs, its construction combines a column wheel endowed with a polished protective cap, as is the tradition at Patek Philippe, and a tooth-wheeled horizontal clutch. The chronograph drive wheel, the clutch wheel and the chronograph wheel present patented profiles that reduce wear, increase the efficiency of energy transmission and avoid all point-to- point contact. Regulating the depth of the gears is not achieved, as is usual, by means of an eccentric, but by a large “eccentric cap” placed on the column wheel that defines the extreme position of the beak of the clutch lever -resulting in more precise adjustment. Notable among the other features optimizing performance are the auto-adjusting zero-reset hammers pivoting between jewels, the system of direct synchronization between clutch lever and brake, and the open-work cam of the minute-counter, conceived to damp shocks during the zero re-set.
Comprising an impressive 500 parts, the new manually wound caliber CH 29-535 PS QI is regulated by a Gyromax® balance with a Breguet overcoil balance spring, oscillating at a frequency of 28,800 vibrations per hour. It ensures a power reserve of between 55 and 65 hours (chronograph disconnected). Its architecture and lavishly hand-finished and decorated parts may be admired through the transparent case-back in sapphire crystal, bearing the inscription “Patek Philippe Milano 2026”.
Calatrava case in platinum
Reference 5978P-010 is presented in a classic, understated Calatrava case, 42mm in diameter. Crafted in platinum and polished by hand throughout, it is distinguished by its concave bezel and delicately hollowed, incurved lugs. The rectangular push-pieces, with their subtly softened angles, blend elegantly with its profile. Like all Patek Philippe’s platinum models, this timepiece is adorned with a brilliant-cut diamond, set discreetly at 6 o’clock.
Navy-blue sunburst dial uniting elegance with legibility
With its caliber based on the combination of two emblematic Patek Philippe mechanisms, the dial of Reference 5978P-010 retains an undeniable likeness, while displaying its own fully assumed modernity. The navy-blue sunburst surface with a black gradient rim catches the eye with its technically sophisticated play of relief effects. Its center is slightly concave and textured, while the counters at 3 o’clock and 9 o’clock, also on a level of their own, present a snailed decoration. The dial’s multi-level construction and play of textures enhances legibility. The applied faceted baton-type hour markers in white gold, harmonizing with the luminescent white of the coating on the minute scale and on the white- gold dauphine-type hands, ensure optimal legibility under all conditions.
The calendar indications, in Italian, appear in three apertures arranged along an arc in the upper part of the dial, each clearly delineated by its white-gold frame. The main aperture, devoted to the date, stands out by its slightly larger size compared with the day and month apertures, emphasizing its central function in the display of the calendar information. Completing this display is a moon phase aperture at 6 o’clock and two round apertures, for the day/night indication and the leap-year cycle, at 8 o’clock and 4 o’clock respectively. Varnished in red, the central chronograph hand in Pfinodal® and the white-gold hand of the instantaneous 30-minute counter add a dynamic touch.
This sporty temperament is underlined by a strap in a composite material with a fabric motif, in navy- blue with red contrasting stitching. A subtle detail: the tricolor stitches that finish off the strap’s topstitching discreetly take up the colors of the Italian flag. The patented triple-blade fold-over clasp in platinum ensures safety and comfort.
