Cubitus Perpetual Calendar Skeleton

Press release

Cubitus. Perpetual Calendar Skeleton Reference 5840P-001
The first grand complication in the Cubitus collection

Patek Philippe continues to enrich its Cubitus collection, introducing the line’s first Grand Complication. Uniting the rigorous principles of horological technique with a bold modern aesthetic the new Cubitus perpetual calendar Reference 5840P stands out by its skeletonized design, where the pierced parts subtly reveal the complexity of its mechanical heart and the wealth of painstaking finishing touches. The case and the movement were conceived as a single harmonious whole, designed to highlight both the technical precision and the beauty of every detail.

Sporty elegance and mechanical complexity

The elegantly sporty Cubitus collection made its debut in October 2024 with 3 inaugural large-size references. Two models in steel and gold and in steel concentrate on the hours, minutes, seconds and date while a model in platinum is endowed with a movement combining an instantaneous grand date, day of the week and moon phases, and the indication of the small seconds. In 2025 the Manufacture brought out two new medium-size references, in rose gold and in white gold. On the occasion of Watches and Wonders 2026, Patek Philippe continues to enrich this collection by introducing the line’s first Grand Complication: Reference 5840P-001, a perpetual calendar combining a square –shaped skeleton movement with a decidedly modern, assertive aesthetic.

Square-shaped skeletonized caliber with perpetual calendar

With the Cubitus perpetual calendar, Patek Philippe demonstrates once again its ability to approach the design of a watch as a harmonious whole, conceived to reflect both its technical precision and the beauty of each detail. That is how the manufacture approached the development of the new caliber 28-28 Q SQU, whose square shape with rounded corners blends perfectly with the curves of the Cubitus case. Similarly, the architecture of this skeletonized caliber was also developed in line with the collection’s distinctive style. The openworked parts unite to evoke the emblematic motif stamped in relief on the Cubitus dials. This effect tested the limits of what was technically possible while always retaining sufficient matter to ensure the smooth performance and durability that define the Manufacture’s timepieces.

For the first time at Patek Philippe, the movement presents a monochrome aesthetic, enlivened with just a few touches of blue on the screws, which are colored by heat treatment, and on the Calatrava Cross, engraved and varnished by hand on the mini-rotor. The movement plates, the bridges, the wheel plates, the balance and the gold mini-rotor thus share the same rhodium-plated finish, lending a modern, assertive look overall. The attention to detail even went as far as the choice of clear sapphire crystal for the functional jewels - except on the arms of the lever, where they remain red for the purpose of carrying out the precision timing tests. This monochrome treatment brings out the elegance of the fully skeletonized movement architecture, while the elaborate finishing techniques underline the graphic force and visual harmony of its construction. Comprising 313 parts, the new caliber 28-28 Q SQU movement displays the time on the basis of 12 and 24 hours, together with minutes, seconds, date, day of the week, month, moon phases and leap years.

This caliber is an evolution of the caliber 240 Q, which had also to be adapted to the square shape. This was particularly evident as regards the mechanisms that transmit the impulses from the corrector push-pieces on the side of the case to the movement. At the heart of the calendar mechanism is a 48 cam, characteristic of the perpetual calendar in the 240-caliber movement family. It constitutes the memory of the movement’s calendar and completes one rotation every four years. The circumference of this cam is divided into 48 segments, representing the 48 months of a 4-year leap year cycle. The different monthly segments take the shape of different grooves on the rim of the 48 cam. When the large lever probes the outer contour of the cam progressively with a finger-piece over the course of the four years, the calendar mechanism can ascertain, according to the depth of penetration of the finger-piece, whether it is a month with 28, 29, 30 or 31 days. Thus, the calendar always displays the correct date without manual intervention. According to the rules of the Gregorian calendar, valid worldwide, a correction is needed with every complete century (2100, 2200, 2300) because there is no leap year. However, if the last year of the century is divisible by 400, the intercalary day applies and the perpetual calendar requires no adjustment.

A spectacular reproduction of the moon

This is the first model in the regular collection to display the moon phase by means of a large-moon mechanism. The latter takes up the concept of the World Time Moon (References 5575G and 7175R) presented as limited editions on the occasion of the manufacture’s 175th anniversary.

Traditionally, the moon-phase display is based on a disk adorned with two moons, which appear successively in a specially shaped aperture. The disk completes one rotation on its axis over two lunar cycles. To offer a more spectacular display, the Manufacture’s watchmakers imagined a system of “large moon”, based on a single, large-size moon. The gear train’s reduction system was adapted accordingly so that the moon disk completes one rotation for every lunar cycle, i.e. every 29.53 days.

This strikingly realistic large moon phase also stands out by the minute attention to detail and the play on different materials to reproduce all the poetry of the lunar relief. This captivating effect was achieved by means of two extremely thin disks, both in mineral glass. The first disk is decorated with stars engraved and metalized on its underside, while blue varnish conjures up the depths of the night sky. The second disk, in the shape of an applique, depicts the moon and is set into a housing machined in the surface of the first main disk. The underside of this second disk was adorned with black metallization and structured by laser to reproduce, with great precision, the relief of our natural satellite.

The nobility of platinum

For this first grand complication to join the Cubitus collection, Patek Philippe chose platinum, the most noble of metals. Retaining the characteristic two-part construction with lateral lugs, the case also conserves the dimensions of the large-size Cubitus models, with a diameter of 45mm. Despite the complexity of its movement, its profile remains surprisingly slender, with a height of only 10 mm. The design, based on a square with rounded corners, is set off to perfection by its alternating polished and vertically satin-brushed surfaces. Similarly to all the Patek Philippe models in platinum, this Cubitus model is adorned with a diamond, here a baguette cut harmonizing with the case design, set into the bezel at 6 o’clock. 

The openworked dial of the Cubitus Perpetual Calendar Reference 5840P-001 drew inspiration from the linear decor that distinguishes the models in the Cubitus collection. Its fine laser-cut strips reproducing the linear decor line up perfectly and harmoniously with the openwork on the movement plate and the bridges. A horizontal satin-brushed finish lends sparkle to their coating of blue PVD. The applied hour markers, in white gold with a luminescent coating, seem to float on the surface of the dial. Rounded baton-type hour and minute hands in 18K white gold also have a white luminescent coating. The other hands, these too in white gold, are coated with white lacquer. The different finishes and textures strengthen the three-dimensional effect and sense of depth while ensuring optimal legibility.

The strap, in an ultra-resistant composite material with a textile motif, in navy blue with cream contrasting stitching, underlines the watch’s modern technical style. It is secured by a folding buckle in platinum with three independent catches, engraved with the name of the Cubitus collection.