Fortunately, it is not all teary-eyed past-reviving that is occurring at this anniversary — kudos to AP for it. Accordingly, alongside the re-edition Royal Oak Offshore Selfwinding Chronograph, we see the launch of the brand new Royal Oak Offshore Tourbillon Chronograph, namely Ref. 26421ST and 26421OR, which have an entirely new layout in two different case materials.Based on two earlier Audemars Piguet Royal Oak Offshore Tourbillon Chronograph watches, specifically the Ref. 26388PO (watch our hands on with it here) and 26288OR, those new Royal Oak Offshore Tourbillon Chronograph watches come in stainless steel and 18k rose gold respectively, and feature a new case design that has a thinner bezel and a more open dial. Even so, the distinctive Royal Oak Offshore design characteristics are intact. The 45mm instance is still angular, the bezel remains octagonal, and there is no missing those vulnerable hexagonal screws around the bezel. Completing the look are black ceramic pushers to your chronograph and a screw-down crown. Water resistance is also 100m. On the dial, an individual can observe the exposed movement and the tourbillon in 9 o’clock. Opposite the tourbillon in 3 o’clock is the 30-minute counter to get the chronograph. Also clearly visible are the two mainspring barrels. The skeletonized bridges extend from each of the eight screws in a way that is rather distinctive and ties the design of this case, dial, and movement together in a way few watches manage to do so.These watches are powered with the in-house hand-wound Caliber 2947, which is an open-worked variant of the Caliber 2933 located in the Royal Oak Offshore Tourbillon Chronograph Ref. 26388PO & 26288OR. This specific movement features 338 parts, an incorporated chronograph movement that has a column wheel mechanism, a heartbeat rate of 3Hz, and a power reserve of a whopping 237 hours. Royal Oak Offshore fanatics are certainly eager to understand the costs, and we’ll update the article when we can confirm. Every Audemars Piguet Royal Oak Offshore Tourbillon Chronograph 25th Anniversary model is limited to 50 pieces.
The perpetual calendar complication reached the wristwatch soon after it was popularised by troops during the First World War, albeit only in one of a kind timepieces. The first perpetual calendar wristwatch was a one-off timepiece made in 1925 by Patek Philippe, equipped with a movement made for a ladies’ pendant watch. And four years later Breguet completed a perpetual calendar wristwatch with a wristwatch movement. But those wristwatches only had the day, date, month and moon. Despite being de rigueur in modern perpetual calendar wristwatches, the leap year only arrived in the wristwatch in 1955, courtesy of Audemars Piguet.
That was the year Audemars Piguet introduced the reference 5516 perpetual calendar wristwatch, the first serially produced wristwatch with a leap year indicator. By comparison, the first such perpetual calendar from Patek Philippe was only produced in 1981 (and sold in 2013 for US$1.7 million). Only 12 of the ref. 5516 were made, and only nine of those had the leap year indicator. The first three of the ref. 5516 had the moon phase at 12 o’clock and the leap year display at six (Christie’s sold one example for US$314,000 in 2008), before evolving into the final iteration of the ref. 5516. Depicted below, the final version of the reference is arguably the most beautiful, with a visually balanced and functional two-tone dial.
Made in 1957 but only sold in 1969 – the long interval between the two was not uncommon for pricey, complicated watches in the mid-20th century – this ref. 5516 is in yellow gold. And this particular specimen, part of the Audemars Piguet museum collection, is double signed with “Tiffany & Co.” below the watchmaker’s label.
This has a striking two-tone dial, with sunken sub-dials finished with circular graining. The lettering on the dial is prominently raised, because it was made the old fashioned way. Instead of merely being printed, the lettering is created by filling recesses with enamel, a technique known as champlevé. Practically non-existent today, champlevé lettering never fades.
The ref. 5516 is powered by the calibre 13VZSSQP, one of the most important base movements for high-end watches in that era. The VZ series of movements were made by Valjoux, a movement maker now part of ETA. It’s best known for the mass market 7750 chronograph movement now, but it used to make much more refined calibres. Thirteen lignes in diameter, the VZ series eventually evolved into the Valjoux 23, 72 an so on. These movements were used in a variety of watches from the best names in Swiss watchmaking, including the Patek Philippe refs. 1518 and 2499.
Rare and historically important, the ref. 5516 is just one example of why the perpetual calendar is arguably the most significant complication for Audemars Piguet.