At SIHH 2018, amongst the grand debuts like Royal Oak Offshore 25th Anniversary re-issue, the Royal Oak “Jumbo” extra-thin in titanium and platinum, and even the first Royal Oak Concept made specifically for women, there was a sleeper hit. 

It wasn’t displayed in a glass case for everyone to see. Instead, selected guests were offered the opportunity for a private viewing: an R&D watch, in platinum, equipped with the thinnest perpetual calendar movement ever produced.

The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin
The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin

Audemars Piguet has a rich history in producing perpetual calendar watches and thin calibres which has been well documented over the years so the prototype watch had big shoes to fill. 

Dubbed the RD#2 at the time, the watch looked like a Royal Oak which had gone through a successful weight loss programme. The 41mm case size was identical to the current generation perpetual calendar Royal Oak, but the total height of the case was reduced to 6.3mm. To put that into perspective, know that the recently released 41mm self-winding Royal Oak ref. 15500 has a case height of 10.4mm, the existing Royal Oak Perpetual Calendar is 9.5mm thick, and the 39mm Royal Oak “Jumbo” extra-thin comes in at 8.1mm.

The RD#2, Royal Oak ref. 15500, and Royal Oak “Jumbo” extra-thin side by side
The RD#2, Royal Oak ref. 15500, and Royal Oak “Jumbo” extra-thin side by side

To achieve this incredible low height of 6.3mm — with the movement inside — Audemars Piguet re-worked its calibre. It took the smartest people at AP — and I’m talking engineers, designers, programmers and watchmakers — to push the limits of their craft to re-engineer the perpetual calendar movement as we know it. Where the perpetual calendar functions are normally arranged on three levels, they have now been merged into a single layer by integrating the end-of-the-month cam into the date wheel, while the month cam has been combined with the month wheel. This resulted in the all new Calibre 5133 with a mind-blowing total thickness of only 2.89mm–and with a full rotor s’il vous plaît. Of course these new innovations have been patented, paving the way for a future generation of thin and complicated watches.

The new Calibre 5133 has a total thickness of 2.89mm
The new Calibre 5133 has a total thickness of 2.89mm

For me however, one key reason for creating thin watches was to reduce the overall weight of the timepiece; the watch, presented in hefty 950 platinum kind of defeated the purpose. I had a second quibble, which happens on the dial side. The new enlarged sub-dials for the day, date and month, and two tiny sub-dials for the night/day indicator and leap year, coupled with the signature “Grand Tapisserie” pattern, made the dial seem rather busy. A little disconcerting perhaps, since the pattern is a distinct feature of the Royal Oak.

The 2018 Audemars Piguet RD#2 prototype
The 2018 Audemars Piguet RD#2 prototype
The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin
The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin

The Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin

Which brings us to the timepiece we have today which is essentially the RD#2 but cleaned up — and with a longer name but let’s not kid ourselves, everyone will keep calling it the AP RD#2.

I guess I wasn’t the only one who had the same two complaints I mentioned before because when the final production version of the watch came out, only two things were changed, and they are — you guessed it — the dial and material used for the watch.

The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin

The dial does away with the tapisserie pattern and is replaced by a dark blue satin finish which is brushed vertically. The markers are now much more prominent and pop out from the watch face. Watch collector Austen Chu was the first person in the world to get the Royal Oak Selfwinding Perpetual Calendar Ultra-Thin and he tells me, “The satin dial, in my opinion, fits the watch a lot better than the tapisserie dial, and it also makes the watch look thinner on the eyes. The tapisserie pattern brings in a lot of depth. So without the tapisserie dial, it makes the watch look even slimmer.”

Watch: Collector’s Choice with @Horoloupe

The case and bracelet are in titanium and the centre links and bezel are in polished platinum
The case and bracelet are in titanium and the centre links and bezel are in polished platinum
The dial appears differently under various lighting conditions
The dial appears differently under various lighting conditions

The case and bracelet are now in titanium, which makes a lot more sense, and the centre links and bezel are in polished platinum. The result is an attractive juxtaposition of the two metals. The polished platinum bezel almost disappears under certain lighting conditions, which makes the watch look even thinner than it actually is.

The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin
The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin
The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin

All in all, the Royal Oak Selfwinding Perpetual Calendar Ultra-Thin is a great demonstration of Audemars Piguet’s ability to innovate and usher watchmaking into a modern era of technical performances. There is no doubt that we will see more thin and complicated timepieces in the future and the industry might look back to this watch as the launching pad for this trend.

The AP RO Selfwinding Perpetual Calendar Ultra-Thin on the wrist
The AP RO Selfwinding Perpetual Calendar Ultra-Thin on the wrist
As expected, the watch is extremely light to wear
As expected, the watch is extremely light to wear
The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin

Technical Specifications

Movement

Self-winding Calibre 5133; hours, minutes; perpetual calendar with day, date, astronomical moon, month, leap year; night and day indication; 40-hour power reserve

Case

Satin-brushed titanium with polished 950 platinum bezel; sapphire crystal and caseback; titanium screw-locked crown

Strap

Satin-brushed titanium with polished 950 platinum links; titanium AP folding clasp

The 2019 Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin