Calatrava 8 Days

Press release 

Patek Philippe

Watches and Wonders Geneva 2025 April 2025

Calatrava 8 Days Reference 5328G-001

A new movement with instantaneous day/date displays and an 8-day power reserve

Patek Philippe is enriching its range of complications useful in everyday life with a new Calatrava model endowed with instantaneous displays of the day (in an aperture) and the date (by hand) at 6 o’clock and a large power reserve of eight days indicated at 12 o’clock. Equipped with the new manually wound caliber 31-505 8J PS IRM CI J, this timepiece with its decidedly modern aesthetic combines a case in white gold, its caseband adorned with the “Clous de Paris” or hobnail guilloché motif, with a blue dial on which the displays are arranged in an original, highly legible manner on a vertical axis.

Even though they do not appear in the classic catalogue of horological complications, the large power reserves are genuine technical feats, especially in the confined space of a wristwatch. The difficulty is not just that, once wound, the watch must be able to function longer than the usual timepiece, but also –and especially –that it must retain its rate accuracy and stability for the duration of this increased autonomy.

The Patek Philippe engineers have risen brilliantly to this challenge on a number of occasions. In 2000, the manufacture marked the dawn of the third millennium with the 10 Day Power Reserve Reference 5100, a limited edition of 3000 watches, endowed with a rectangular case inspired by the famous “Manta Ray” Reference 2554 of 1954. The world’s first chronometer wristwatch with a power reserve of 240 hours, this manually wound timepiece heralded a trend that others have followed. In 2003, the regular collection welcomed “ 10 Day Tourbillon” Reference 5101P, a platinum watch with a manually wound “form” movement and a rectangular case with tiered flanks inspired by the Art Deco period. A new interpretation of this retro-modern design came out six years later, in rose gold. The year 2013 saw the unveiling of the Gondolo “8 Days, Day & Date Indication” Reference 5200, with a rectangular caliber 28- 20 REC 8J PS IRM C J manually wound movement with instantaneously jumping day and date –an additional challenge in terms of energy.

Earlier, in the 1920s to 1930s, Patek Philippe had created three notable perpetual calendar desk clocks endowed with an eight-day power reserve; a tradition reenergized this spring by the new desk clock with perpetual calendar and weekly calendar, Reference 27000M-001, offering a 31-day power reserve.

A new alliance of tradition and innovation

Patek Philippe is increasing the momentum with a new Calatrava equipped with a new manually wound movement. The product of five years’ development, caliber 31-505 8J PS IRM CI J takes up the base architecture of the rectangular caliber 28-20 REC 8J PS IRM C J launched in 2013 in the Gondolo 8 Days, Day & Date Indication Reference 5200, but with a round shape designed to fit perfectly into a Calatrava-style case. True to the Patek Philippe pioneering spirit, this movement also presents several technical optimizations and innovations, particularly related to energy management and the instantaneous jumps of the day and the date. It was also designed to ensure autonomy of eight full days, with a ninth reserve day flagged in red on the arched indicator at 12 o’clock. The watch continues to function during this ninth day, but risks becoming less accurate, since the amplitude will decrease. To ensure optimal performance it is therefore advisable to rewind at the end of the eighth day at the latest (the movement will stop completely at the end of the ninth day).

An exclusive Pulsomax® escapement.

The challenges posed by the new caliber 31-505 8J PS IRM CI J called particularly for a state-of-the-art regulating organ. This movement is distinguished by its exclusive Pulsomax® escapement with an escape wheel and lever made of Silinvar®, a silicon derivative with unrivaled physical and mechanical qualities (lightness, hardness, resistance to magnetism, etc.). Developed as part of the “Patek Philippe Advanced Research” program, the Pulsomax® escapement is distinguished by its superior performance, achieved in particular thanks to the unique geometry of the escape wheel and lever and the machining precision provided by the DRIE process (Deep Reactive Ion Etching). Its optimized performances and long-term reliability, combined with those of the Spiromax® balance spring in Silinvar®(another “Patek Philippe Advanced Research” development) are valuable assets in guaranteeing a large power reserve of eight days. Following the Annual Calendar Regulator Reference 5235 in 2011 (caliber 31-260 REG QA), the 1/10th of a second monopusher chronograph Reference 5470P-001 in 2022 (caliber CH 29- 535 PS 1/10) and the Reference 5200 Gondolo “8 Days, Day & Date Indication” in 2013 (caliber 28-20 REC 8J PS IRM C J), the new Calatrava Reference 5328G-001 is the fourth Patek Philippe model in the current collection to be endowed with a Pulsomax® escapement.

Two series-coupled barrels 

This watch’s large power reserve is ensured by two barrels series coupled barrel allowing enough energy to be stored for the movement to function precisely for eight full days, with a 9th reserve day. The first barrel is fitted with a slip spring. When the user winds the movement, the two barrels charge simultaneously. As the main barrel discharges, the auxiliary barrel transmits its energy to it, recharging it, according to the principle of communicating vessels.

Instantaneous day and date jumps 

For the instant-jump day and date mechanism, Patek Philippe returned to the principle introduced in the Cubitus Instantaneous Grand Date, Day and Moon Phases Reference 5822P-001, unveiled in October 2024 (self-winding caliber 240 PS CI J LU) –with a 24-hour wheel comprising a cam fitted with a dual- function spring. This system, already patented for Reference 5822P-001, and returning on this new Reference 5328G-001, makes it possible to overcome a higher torque, while guaranteeing precise jumps. Each night, at midnight, the large lever equipped with two beaks falls on the 24-hour cam, and in falling, engages direct with the day star and the date star. The two indications then jump simultaneously and instantaneously, thanks to the energy accumulated throughout the day. The day display is performed by a disk that was lightened and pierced to reduce its weight and its inertia at the moment of the jump – and thereby avoid any undesirable double jump. The date is indicated by a hand positioned on a counter concentric with the small seconds at 6 o’clock. Thanks to the beveled shape of the dual-function spring, the new caliber 31-505 8J PS IRM CI J makes it possible to set the time at any hour of the day or night, backwards or forwards, even during the passage of midnight, with no risk of damaging the movement. Furthermore, the caliber is equipped with a “stop-seconds” function (when the crown is pulled out) enabling the time to be set to the nearest second. The date requires correction five times a year, on the first day of the months of March, May, June, October and December, using the corrector positioned on the caseband between 3 o’clock and 4 o’clock.

An elegant blue dial with a unique face

In addition to its special functions and increased autonomy, the new Calatrava 8 Days Reference 5328G- 001 stands out by its originality as regards the displays. The power reserve indication, transfer printed along an arc (is visible on a subdial at 12 o’clock, while the day aperture, the date hand and the subsidiary seconds dial form a group at 6 o’clock. This arrangement along a vertical axis, particularly legible, also endows the watch with a unique personality. The textured dial in blue with a black gradient rim presents syringe-style applied numerals and hour and minute hands, all in white gold, emphasized by a white luminescent coating.

A case with a Clous de Paris guilloché caseband

The caseband of the round case in white gold is decorated with guilloché work in the Clous de Paris or hobnail pattern. This emblematic decoration first entered the Calatrava collection on the bezel of Reference 96D in 1934 and returned to the spotlight in 1985 on the famous Reference 3919, one of the most beautiful symbols of the Patek Philippe style, which remained in production for more than 20 years. Today, the Clous de Paris motif lends its special aura to a variety of models in the current collection, whether adorning the bezel (Calatrava Reference 6119), the caseband (World Time Minute Repeater 5531, Grandmaster Chime Reference 6300, Annual Calendar Travel Time Reference 5326, Calatrava Reference 5226) or even the dial (Grandmaster Chime Reference (6300), not to mention the Rare Handcrafts models. A refined detail: similarly to References 5326 & 5226, the new Calatrava 8 Days Reference 5328G-001 features an unusual case construction with the lugs attached to the back, enabling the Clous de Paris decoration to wrap elegantly around the entire caseband. A sapphire-crystal case back affords a private view of the architecture of the new manually wound caliber with its Pulsomax® escapement, and of its painstakingly hand-finished parts.

Two interchangeable straps

The new Calatrava 8 Days Reference 5328G-001 is delivered with two straps, one in blue calfskin leather with a textile pattern and cream stitching (originally fitted), the other in grained taupe calfskin leather (additional strap). It is equipped with a new patented triple-blade fold-over clasp that improves safety and comfort and facilitates the interchangeability of the straps by allowing this change to be carried out quickly and easily, without tools.

Patent taken over from caliber 240 PS CI J LU (Reference 5822P-001, 2024)

Cam winding wheel with dual-function spring (European patent application EP4312083) Designed for the driving of the cam by the 24-hour wheel, this system of a winding wheel with a dual- function spring makes it possible to overcome a higher friction force (torque) while guaranteeing the perfect precision of the date jump at midnight. A disconnecting system equipped with a flexible finger- piece that retracts when the 24-hour cam hits the beak of the large lever also enables the user to adjust the time at any moment, backwards or forwards, even during the passage of midnight, without risk of damaging the movement.