Side by Side: Two Audemars Piguet Royal Oak Perpetual Calendars in Black Ceramic — Openworked v. Non-openworked

A face-off between two iconic pieces in their own right.
By Kevin Cureau

Ceramic's Intro to the Industry

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The Audemars Piguet Royal Oak Offshore Diver ref. 15707CE: AP's first all-ceramic watch. (2013)

Introduced to watchmaking in the 1980s by brands such as IWC and Rado, ceramic has evolved from a rarely-used ‘futuristic’ material to a somewhat normalised one amongst luxury watchmakers. While rarely utilised throughout the entirety of a timepiece's construction, some brands have shifted their focus to the material thanks to its numerous advantages over more conventional materials like stainless steel. Today we will explore two ceramic variants of the iconic Audemars Piguet Royal Oak and see what makes them unique, and their material so wonderful.

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The ref. 26579CE and its openworked counterpart, the ref. 26585CE.

Innovation in their DNA

Audemars Piguet have indubitably been a driving force for innovation in the watchmaking industry for decades, if not centuries. While AP's critics often cite their perceived reliance on the Royal Oak for design inspiration, the same critics cannot say that AP does not innovate. From things like the world's first wristwatch minute repeater to the world's first perpetual calendar with a leap year display; there is a reason AP are in the holy trinity of watchmaking. They have earned their stripes fair and square.

The two pieces we will be discussing here are a part of that drive to innovate within the industry. Both featuring black ceramic cases and bracelets, the Royal Oak Perpetual Calendar and the Royal Oak Perpetual Calendar Openworked have contributed significantly to the current widespread adoption of ceramic as a material in luxury watchmaking.

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As mentioned earlier, AP wasn't the first to use ceramic in their watches; but in 2017 when they released the Royal Oak Perpetual Calendar ref. 26579 in black ceramic at SIHH, something finally clicked. Having just rebirthed the Royal Oak Perpetual Calendar two years prior, this release marked the first time a fully ceramic construction would marry two of the Maison's most prized assets, the Royal Oak and perpetual calendar, and slingshot them into the 21st century. An instant hit, the watch was the talk of the fair — with the piece quickly racking up a healthy waiting list almost immediately. All of a sudden, ceramic was making headlines.

Why Ceramic

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As is often the question whenever a brand introduces a new material to their portfolio, you may ask why that material is so special, with ceramic being the material in question here, of course. Rado introduced a ceramic case and bracelet watch in 1990, so why was this so different? Well, the answer to that question lies in AP's approach to the material. They sought to finish their ceramic to the same standard of the metal in their 'regular' Royal Oaks. Before getting into ceramic's properties, let's just say that's a difficult thing to do.

What Makes it Special

One of ceramic's most beneficial features, while also its most significant stumbling block, is its hardness. Almost impossible to scratch, ceramic is 3.5 to 4 times harder than steel — which means it can be brittle. While a ceramic watch can look absolutely brand new for decades, it is painstaking to finish to a high degree and requires careful planning and execution. Given its hardness, it is no surprise the ceramic bracelet took five times longer to complete than its steel counterpart, with a total work time of around 30 hours.

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The ceramic bracelet of these pieces took five times longer to complete than their steel counterparts.

In terms of planning, AP couldn't just use the old template they had from their metal Royal Oak bracelets. They had to completely rethink how they would manufacture the Royal Oak's bracelet. As ceramic can be brittle, it took AP 600 hours of research and development to get the bracelet right. Even with its unusually shaped links, they cracked the code and ensured the Royal Oak's bracelet could be made to their exact standards without sacrificing structural integrity.

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Beyond the Material

Ceramic finally aside, the ref. 26579CE and its openworked counterpart, the ref. 26585CE, have one overwhelmingly noticeable difference between them: their dials. Starting with the ref. 26579CE, which sports a slate grey dial with AP's signature "grande tapisserie" pattern. Featuring white lettering, except for the red '31' in the 3 o'clock date subdial, the dial is uniform and legible.

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The ref. 26579CE sports a slate grey dial with AP's signature "grande tapisserie" pattern.

Further adding to its legibility is the dial's layout. Everything is proportional and spaced out by displaying the day, date, month, leap year and moon phase in their own subdials. Where some brands might squeeze 48 months together to simplify mechanics behind the leap year indicator, AP has given this movement an independent leap year indicator that forms part of the subdial at 12 o'clock. Also displaying the week of the year along the dial's periphery, you'll never again have to wonder how many more weeks it is until Christmas.

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The Openworked ref. 26585CE features a stunning openworked dial with rose gold accents throughout.

Next up, the Openworked ref. 26585CE features a stunningly gorgeous openworked dial with rose gold accents throughout. With the same dial layout and functions as the aforementioned ref. 26579CE, the Openworked comes with a level of depth that only Audemars Piguet could achieve. Peering beyond the sapphire dial, we can see the stunningly finished movement that lies beneath — with its hypnotic gears, dizzying springs and beautiful bridges.

While it might be unfair to compare these two dials, thanks to the Openworked's advantage of what lies beneath its sapphire, both of these watches are visually intriguing in their own right. Where the Openworked excels in its spellbinding complexity, its sibling excels in stylistic conservatism. It is essential to recognise that not everyone wants their watch to be as loud as the Openworked.

However, it is ironic that AP quietly added the Openworked to their website in 2019 without a whisper to the press, whereas the ref. 26579CE, with its quieter dial, was released at a trade fair and caused pandemonium.

It's What's Inside That Counts

Determined to do their perpetual calendars proud, AP fitted the ref. 26579CE with their cal. 5134 and the Openworked ref. 26585CE with the cal. 5135, the 5134's openworked counterpart. A tribute to their skill as watchmakers, AP managed to squeeze these incredibly complex movements into 9.5mm and 9.9mm thick cases, respectively.

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The ref. 26579CE is powered by cal. 5134.
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The openworked ref. 26585CE is powered by cal. 5135.

Not easy to achieve in a steel watch, this feat is even more impressive considering both timepieces are made of ceramic. Rounding off an incredible pair of watches, not only are their movements complex and impressive, even their material is insanely complex and impressive. When it comes to material innovation and technical mastery, it’s safe to say that Audemars Piguet are one of the best in the business.

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Specifications

Audemars Piguet Royal Oak Perpetual Calendar ref. 26579CE
Reference number: 26579CE
Case size: 41mm
Thickness: 9.5mm
Material: Black Ceramic 
Crystal: Sapphire
Water-resistance: 20m
Movement: Calibre 5134
Functions: Perpetual calendar with week indication, day, date, astronomical moon, month, leap year, hours and minutes.
Winding: Selfwinding
Frequency: 2.75 hz / 19800 vph
Power reserve: 40h
Strap: Black ceramic bracelet with titanium AP folding clasp
Retail price: HKD 804,000 / CHF 93,349

Audemars Piguet Royal Oak Perpetual Calendar ref. 26585CE
Reference number: 26585CE
Case size: 41mm
Thickness: 9.9mm
Material: Black Ceramic 
Crystal: Sapphire
Water-resistance: 20m
Movement: Calibre 5135
Functions: Perpetual calendar with week indication, day, date, astronomical moon, month, leap year, hours and minute.
Winding: Selfwinding
Frequency: 2.75 hz / 19800 vph
Power reserve: 40h
Strap: Black ceramic bracelet with titanium AP folding clasp
Retail price: Approx. HKD 1,119,605 / CHF 130,000 

For further information about the ref. 26579CE and the ref. 26585CE, visit Audemars Piguet online. 

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