[A deep dive into the new 2025 models!] Audemars Piguet's 150th anniversary model may look unassuming at first glance, but it's actually an unprecedented perpetual calendar!

Audemars Piguet will celebrate its 150th anniversary in 2025, and to mark this milestone, they have released a new perpetual calendar model. Some have asked if they hadn't made other masterpieces, but considering that the company returned to the world of complications with the perpetual calendar in 1978, it makes sense that they chose to focus on perpetual calendars. And this new perpetual calendar has enough features to warrant its release as a standalone product: it is the most user-friendly mechanical perpetual calendar in history.

The perpetual calendar that brought Audemars Piguet fame

　From its founding in 1875 until the mid-1940s, Audemars Piguet was primarily a watch manufacturer specializing in complications. One of its signature mechanisms is the perpetual calendar, which automatically adjusts for leap years. The company released its first wristwatch with a perpetual calendar in 1955, but it wasn't until 1978 that it became a signature feature of the company.

　The Caliber 2120/2800, released in 1978, was the world's thinnest automatic perpetual calendar movement at the time, measuring just 3.95mm thick. This record was made possible by adding a Dubois-Dépraz module to the 2.45mm thick Caliber 2120. Dubois-Dépraz, which had been manufacturing general-purpose modules, began producing high-quality modules using wire EDM machines and other techniques. In collaboration with Audemars Piguet, they perfected the perpetual calendar module. This was the first perpetual calendar in watch history to be mass-produced (though only 7000 were produced over the next 16 years). This movement and module were eventually adapted for the Royal Oak, ushering in a new trend in complications—the "complex sports watch" genre.

The appearance is almost the same, but the contents are completely different: the new "Perpe"

　The 150th anniversary model, announced on February 25, 2025, is a signature Audemars Piguet design, featuring a perpetual calendar. The newly developed automatic perpetual calendar movement, Cal. 7138, features an ergonomic design. Specifically, it features an "all-in-one" crown that allows all functions to be adjusted with just the crown, allowing the user to adjust the perpetual calendar without the use of tools. According to the company, the development took five years and five patents were obtained. While the appearance is nearly identical to conventional perpetual calendars, the internals are completely different.

What's different about the new "Perpe"?

　While existing perpetual watches use a push button on the side of the case to adjust the calendar, the new one allows you to operate everything using just the crown. However, this idea itself is by no means new. The Da Vinci Perpetual, completed by IWC in 1985, was an excellent watch that allowed you to fast-forward all calendar settings simply by pulling the crown out one notch and turning it to set the date. In my opinion, this is the most sophisticated perpetual calendar available.

　Lucas Raggi, who is involved in the development of complicated watches at Audemars Piguet, said, "IWC's perpetual watches are great," but explained that if you advanced the calendar too far, you had no choice but to stop the watch until the day came, or have it serviced to have the calendar adjusted. "Also, if you turn the crown too quickly, the calendar may jump." As an aside, while IWC perpetual calendars boast an extremely high level of perfection, I don't recommend turning the crown too quickly.

　So Audemars Piguet changed the crown to three positions (!), allowing the date, year, day of the week, and moon phase displays to be individually adjusted by simply turning the crown. While there are other examples of pushers with multiple functions, such as A. Lange & Söhne's Odysseus Chronograph and Audemars Piguet's masterpiece (and we can honestly say that), the CODE 11.59 by Audemars Piguet Ultra Complications Universelle RD#4, there is no other example of a crown with so many functions.

　The crown position
1st stage: Manual winding
2nd row: Turn up to adjust the date, turn down to adjust the month
Step 3: Adjusting the hour, minute and 24-hour hands

　Now, one more thing. If you push it from the third row to the second row,

Second position (returned from third position): Turn up to adjust the day and week, turn down to adjust the moon phase display

　Although it may look complicated at first glance, it's easy to understand that the date, month, day of the week, and moon phase displays are all linked together. Anyone who buys the watch will be able to operate it easily after just a few uses. In fact, I learned how to operate it after just two touches.

The extraordinary "all-in-one" crown

　The "all-in-one" crown adjusts the calendar by pulling it out three notches (and then out one notch). It's a magical mechanism, but it's not difficult at all once you hear the explanation. The mechanism around the crown spreads out like a fan, with the crown's winding core as its axis. When the crown is pulled out, this fan-shaped part moves up and down, and the gears that mesh with it (which themselves move) advance the date, month, and moon phase displays.

　Making the hand-setting mechanism, which is subject to heavy loads, so complex would theoretically reduce durability and make it feel wobbly to begin with. However, the crown feels extremely smooth, and even a three-position (!) crown can be operated reliably. When I asked Rudge why it was so smooth, he said, "Actually, we figured out the optimum force required to pull out the crown, and then designed the crown and its surroundings from there." In other words, the design was undertaken not with a design in mind, but with consideration given to the actual usage situations.

There's more. This "Paper" is user-friendly.

　This new perpetual calendar allows all mechanisms to be adjusted with a three-position crown. Additionally, Audemars Piguet has incorporated numerous user-friendly features. One such feature is the date adjustment. Pulling the crown out one position and turning it upwards allows the date to advance quickly. However, it takes two to three full turns to advance quickly. The deliberate play in the adjustment mechanism is intended to prevent the date from changing accidentally. Additionally, the calendar cannot be adjusted between 9 PM and 3 AM (highlighted with a red line on the subdial at 9 o'clock). Making it impossible to adjust the calendar at all, rather than indicating a prohibited time period, is user-friendly. However, some of the prototypes I tested had incomplete adjustments in this area, and some still functioned.

　This new perpetual calendar is thoroughly user-friendly. The date display at 12 o'clock symbolizes this approach. While a typical calendar would have "31" at the top, this movement has "1" instead. However, that's not the point. The intervals between each date have been subtly adjusted, with some being narrower and others being wider.

　This was made possible by a "progressive step" disc, for which a patent is currently pending. Unlike ordinary gears, this disc has unevenly spaced teeth, allowing for uneven display. According to Rudge, "The gears were manufactured using a regular milling cutter, not a wire EDM machine." He added, "Since the required machining precision could be achieved using a milling machine, there was no need to make it using UV-LIGA, right?"

　There's also a reason why it's so thin despite being packed with features.

　The Caliber 2120/2800, introduced in 1978, featured a Dubois-Dépraz perpetual calendar module, which, although adapted for wristwatches, was essentially a miniature version of the classic perpetual calendar.

　In contrast, Audemars Piguet significantly evolved the perpetual calendar in the 2018 Royal Oak RD#2. The previous three-layer 48-month and 31-day cams were replaced with a single layer, and the levers were redesigned so that the main calendar components are held in place by the dial rather than the bridge. This is why the case thickness of this model is only 6.3mm.

　Rudge explains, "The new perpetual calendar needed to be the same thickness as the existing Perpetual." To that end, the perpetual calendar mechanism is integrated into the movement rather than being a module (Rudge noted that it's not currently possible to incorporate it into the new in-house Caliber 4300 or Caliber 4400 series), and the calendar mechanism partially borrows from the RD#2 design. Additionally, the complex "all-in-one" crown mechanism, some of which don't have bridges supporting them from above, further slims the movement. Despite this, Rudge explains, "it can withstand a one-meter drop test onto a wooden floor."

Three models released to commemorate the 150th anniversary

　Audemars Piguet released the following three models:

"Royal Oak Perpetual Calendar"

　The Royal Oak Perpetual Calendar, with its 41mm stainless steel case, features a blue PVD-coated Grand Tapisserie dial. While it looks almost identical to the previous model, the 24-hour display at 9 o'clock indicates that it is powered by a new movement.

　The blue PVD color is quite good, but it does not interfere with visibility, which is typical of modern Audemars Piguet.

　The 18K sand gold model also comes with a dial in the same color.

　Matching neutral colors is quite difficult, but Audemars Piguet has been focusing on exteriors for the past few years, and it seems they have mastered it. The sense of unity between the interior and exterior may be the best Audemars Piguet has ever created. In both cases, the exterior finish is impeccable.

"CODE 11.59 by Audemars Piguet Perpetual Calendar"

　The same movement is used in the "CODE 11.59 by Audemars Piguet Perpetual Calendar," which combines a 41mm 18K White Gold case with a smoke blue PVD dial. The addition of a week display on the outer flange of the dial gives the dial a much cleaner look.

　As expected, the interior and exterior finish of this model is impeccable.

150th anniversary model also available

　To commemorate the company's 150th anniversary, each of the three models above is also available in a limited edition of 150 pieces. These limited edition models feature a specially designed "150" logo and the inscription "1 of 150 pieces" around the outer edge of the case back. The moon phase display at 6 o'clock also features a vintage-style "Audemars Piguet" logo.

THE BEAT GOES ON...

　Audemars Piguet's 150th anniversary kicked off with a seemingly unassuming, yet extraordinary, perpetual calendar. While it may seem like an ordinary perpetual calendar, its thoroughly user-friendly design makes it a fitting tribute to Audemars Piguet's 150 years as a manufacturer of complicated watches. To be honest, it will be difficult to get your hands on any of the models (especially the 150th anniversary limited edition). However, I can assure you that each watch is worth it. This is just the first in the celebration of the 150th anniversary. Audemars Piguet's theme for this year is "THE BEAT GOES ON"!