The Pinnacle of Watchmaking Artistry
Few watches command as much reverence as the Audemars Piguet Royal Oak Perpetual Calendar Openworked (Ref. 26585CE). This timepiece is not just a watch—it’s a mechanical sculpture, a testament to Audemars Piguet’s relentless pursuit of horological perfection. Combining the Royal Oak’s legendary design with a skeletonized perpetual calendar movement, this watch is a harmony of form and function, designed for those who appreciate both technical mastery and aesthetic brilliance.
In this review, we’ll dissect every aspect of the 26585CE, from its openworked dial and ultra-thin case to its highly complex movement and wearability. Whether you’re a seasoned collector or an enthusiast looking to invest in a grail-level piece, this analysis will help you understand why this watch stands as one of Audemars Piguet’s greatest achievements.
A Skeletonized Icon
The Royal Oak Perpetual Calendar Openworked retains the DNA of Gérald Genta’s original 1972 design while pushing boundaries with its skeletonized architecture. The 41mm black ceramic case is a modern twist on the Royal Oak’s stainless steel legacy, offering a stealthy yet luxurious presence.
Key Design Elements:
- Openworked Dial: The skeletonized Calibre 5135 is on full display, revealing the intricate gears, levers, and springs that power the perpetual calendar.
- Black Ceramic Case & Bracelet: Lightweight, scratch-resistant, and exquisitely finished with satin brushing and polished bevels.
- Tapisserie-Free Dial: Unlike traditional Royal Oaks, this model forgoes the guilloché dial for a fully exposed movement, enhancing its avant-garde appeal.
- Blue Calendar Subdials: A subtle pop of color against the monochromatic movement, ensuring legibility while maintaining visual harmony.
The result is a watch that feels both futuristic and timeless, a perfect marriage of Royal Oak heritage and cutting-edge craftsmanship.
Movement: The Heart of Complexity
At the core of this masterpiece is the Calibre 5135, an ultra-thin, self-winding perpetual calendar movement with openworked architecture.
Technical Highlights:
- Perpetual Calendar Mechanism: Tracks day, date, month, leap years, and moon phases without manual adjustment until 2100.
- Skeletonized Construction: Every bridge and plate has been meticulously hollowed out, revealing the micro-engineering marvel beneath.
- Ultra-Thin Profile (4.3mm): Despite its complexity, the movement remains remarkably slim, allowing for a wearable case thickness of 9.5mm.
- 40-Hour Power Reserve: Respectable for a perpetual calendar, though daily wear is ideal.
The finishing is exemplary—beveled edges, polished screws, and Geneva striping showcase Audemars Piguet’s uncompromising attention to detail.
Wearability: Surprisingly Light, Undeniably Luxurious
Despite its 41mm case, the black ceramic construction makes it lighter than steel or gold Royal Oaks. The bracelet is ergonomically curved, hugging the wrist comfortably.
On-Wrist Impressions:
✔ Lightweight yet substantial—ceramic provides a premium feel without heft.
✔ Slim profile (9.5mm) slips easily under a cuff.
✔ Bracelet flexibility ensures a snug fit.
However, the openworked dial can be slightly harder to read at a glance compared to traditional Royal Oaks—this is a watch for those who prioritize artistry over pure functionality.
Complications: The Genius of the Perpetual Calendar
A perpetual calendar is one of watchmaking’s most revered complications, and Audemars Piguet’s execution is flawless.
How It Works:
- Automatic Month & Leap Year Tracking: No manual adjustments needed until 2100.
- Moonphase Precision: Accurate to one day every 125 years.
- Subdials Layout:
- 12 o’clock: Month & leap year
- 3 o’clock: Date
- 9 o’clock: Day
- 6 o’clock: Moonphase
Unlike some perpetual calendars, this one avoids clutter, thanks to the openworked design’s negative space.
Finishing & Craftsmanship: A Cut Above
Audemars Piguet’s hand-finishing is among the best in Switzerland.
Standout Details:
- Chamfered Bridges: Each angle is hand-polished for a mirror-like shine.
- Circular-Grained Mainplate: Adds texture to the movement.
- Black-Polished Screws: A signature of high-end watchmaking.
The ceramic case’s satin finish contrasts beautifully with the polished bezel screws, reinforcing the Royal Oak’s industrial elegance.
Rarity & Exclusivity
This isn’t a mass-produced watch. Black ceramic Royal Oaks are rare, and adding a skeletonized perpetual calendar makes this one of AP’s most exclusive models.
Market Position:
✔ Limited production ensures long-term collectibility.
✔ High demand among Royal Oak enthusiasts.
✔ Strong secondary market value (often selling above retail).
Price & Value Proposition
With an MSRP around $150,000, this is a serious investment.
Is It Worth It?
✔ Yes, if: You value ultra-high-end complications, ceramic luxury, and Royal Oak prestige.
✖ No, if: You prefer simpler, more legible watches or better value propositions (e.g., Patek 5740).
For the right collector, this is a grail-worthy masterpiece.
Alternatives to Consider
If the 26585CE is beyond reach, consider:
- Patek Philippe Nautilus 5740 (Perpetual Calendar) – More classic, but not openworked.
- Vacheron Constantin Overseas Perpetual Calendar – Sporty yet elegant.
- Breguet Classique Perpetual Calendar – Traditional haute horlogerie.
However, none match the Royal Oak’s bold, skeletonized aesthetic.
A Mechanical Marvel for the Discerning Collector
The Audemars Piguet Royal Oak Perpetual Calendar Openworked (26585CE) is a horological masterpiece—a perfect fusion of iconic design, cutting-edge materials, and mechanical ingenuity. It’s not just a watch; it’s a statement of artistry and engineering.
Who Should Buy It?
- Serious collectors seeking a rare, high-complication Royal Oak.
- Luxury investors who appreciate limited-production Audemars Piguet models.
- Horology enthusiasts who want one of the finest skeletonized watches ever made.
If you’re ready to own one of AP’s most extraordinary creations, this watch is worth every penny.
Final Score: 9.8/10
- Design: 10/10
- Movement: 10/10
- Wearability: 9/10
- Value: 9/10
A near-perfect watch for those who demand the absolute best.