A revolution through simplification

Swiss watchmaking has thrived for centuries on a peculiar dichotomy: creating ever more complex mechanical solutions, then convincing wealthy patrons they desperately need them. Audemars Piguet, celebrating 150 years of existence, has taken a refreshingly different approach with their latest horological tour de force – they’ve actually made something complicated easier to use.

The new Calibre 7138 perpetual calendar movement represents a quantum leap forward in user experience. For the first time ever, a perpetual calendar can be completely adjusted via the crown alone – no fiddly pushers, no special tools, and no risk of damaging your six-figure investment while trying to correct the date after leaving it in a drawer for a month. This might sound like a small thing, but in the world of mechanical complications, it’s the equivalent of replacing a horse-drawn carriage with a Tesla.

Five years of research and development culminated in this ingenious system, protected by no fewer than five patents. The result merits genuine praise – a perpetual calendar that doesn’t require an engineering degree to operate, housed within three distinctive 41mm models that showcase the versatility of this new movement.

Crown jewels: engineering ingenuity

The traditional perpetual calendar wristwatch typically features multiple correctors embedded in the case sides – small, recessed buttons requiring a special tool to adjust various calendar functions. Leave your watch unwound for a week and you’ll face a tedious reset process, carefully prodding and pushing with a stylus while consulting the manual to avoid costly damage.

Audemars Piguet’s engineers have banished this inconvenience with their “all-in-one” crown system. The innovation introduces four distinct crown positions that ingeniously control every function. Position one winds the watch clockwise. Pull the crown to position two, and you can set the date clockwise while adjusting the month and leap year counter-clockwise. Position three allows bidirectional time setting. The masterstroke comes with position “2-prime,” accessed by pushing the crown back one step, which enables day and week adjustments clockwise and moon phase corrections counter-clockwise.

This seemingly simple interface conceals a complex internal mechanism featuring an innovative lever and wandering wheel system that meshes with the calendar wheels depending on crown position. The engineering breakthrough earned two patents: one for the crown correction system with its unique “2-prime” position, and another for the month and date crown adjustment mechanism.

The result transforms the perpetual calendar from a beautiful but occasionally cumbersome complication into something genuinely practical for daily wear. It’s the difference between admiring a vintage Ferrari in your garage versus actually driving it daily.

Harmonious display: form follows function

Behind every great movement lies a great dial, and the Calibre 7138 doesn’t disappoint. The displays have been completely reorganized, prioritizing both legibility and aesthetic harmony with scientific precision.

The dial now features a European date arrangement – day at 9 o’clock, date at 12, and month at 3 o’clock. Week numbers printed on the inner bezel now logically begin with week 1 at 12 o’clock rather than week 52. Similarly, “Monday” and “1” align at 12 o’clock in their respective subdials, marking the logical start of both week and month.

Technical ingenuity continues with a patented progressive date display at 12 o’clock. The watchmakers developed a date wheel with 31 custom-made teeth, varying in size to accommodate the different widths of the numerals – ensuring perfect spacing and enhanced readability regardless of whether you’re looking at the 1st or the 31st.

Perfect symmetry between the 3 o’clock subdial (month and leap year) and 9 o’clock subdial (day) has been achieved by adding a 24-hour indicator within the day display. A red zone between 21:00 and 03:00 warns users against adjustment during the movement’s critical automatic date change period – though attempting adjustments during this time won’t damage the movement, contrary to many perpetual calendars.

The moon phase at 6 o’clock, based on an actual NASA photograph, completes the layout with the full moon precisely aligned with the 12 o’clock axis, reinforcing the dial’s perfect visual balance.

Three distinctive personalities

The mechanical marvel that is Calibre 7138 debuts across three distinctive 41mm models, each benefiting from improved water resistance thanks to the absence of case-side correctors.

The Code 11.59 interpretation showcases the collection’s signature architectural approach in 18-carat white gold. Its blue PVD dial features a mesmerizing pattern of concentric circles punctuated by hundreds of tiny perforations, creating a play of light and shadow that adds remarkable depth. Developed with Swiss guilloché artisan Yann Von Kaenel, who hand-engraved the original stamps, this pattern debuted in 2023 and perfectly complements the complicated movement within. White gold luminescent hands and hour markers provide ideal contrast, while a blue rubber-coated strap with calfskin lining and textile pattern adds contemporary flair.

The first Royal Oak variant delivers quintessential AP sporting elegance, pairing stainless steel case and bracelet with a blue PVD Grande Tapisserie dial. The iconic textured surface extends across the subdials and inner bezel, with 18-carat white gold hands and hour markers filled with luminescent material ensuring perfect legibility. White calendar indications complete the two-tone aesthetic.

Perhaps most intriguing is the second Royal Oak, crafted in 18-carat sand gold – a precious alloy introduced to the collection in 2024 that combines gold with copper and palladium. This chameleon-like material shifts between white and pink gold depending on ambient light conditions, creating a uniquely warm appearance. The monochromatic Grande Tapisserie dial, subdials and inner bezel match this sand gold hue precisely through galvanic treatment, with white gold hands and hour markers providing subtle contrast against black calendar indications.

All three models feature sapphire casebacks revealing the movement’s refined finish, including an openworked oscillating weight in 22-carat pink gold and a distinctively positioned barrel bridge visible between 12 and 3 o’clock.

Engineering excellence, practical luxury

What makes this new perpetual calendar truly special isn’t just its technical brilliance or aesthetic refinement – though it has both in abundance. The real achievement lies in Audemars Piguet’s recognition that true luxury combines beauty with genuine usability.

By eliminating the need for correction tools and simplifying the adjustment process, the Swiss manufacturer has transformed one of horology’s most prestigious complications from an occasional-wear showpiece into a genuinely practical daily companion. The crown-based adjustment system represents that rarest thing in luxury watchmaking: genuine innovation that actually improves the owner’s experience rather than simply adding complexity for complexity’s sake.

As Audemars Piguet celebrates its 150th anniversary, Calibre 7138 demonstrates why the brand continues to thrive. Rather than resting on its considerable heritage, AP has reimagined a classic complication for contemporary lifestyles – proving that even after a century and a half of watchmaking excellence, there remain new frontiers to explore in the mechanical art of timekeeping.