The Audemars Piguet Royal Oak Perpetual Calendar ref. 25829OR is a masterpiece of skeletonization, produced between 1996 and 2013 in very few pieces. Made in rose gold, it is in extraordinary condition, with a fine contrast between the case and the intricate openworked and hand-engraved mechanism.
It mounts caliber 2120/2802_SQ, whose manufacture took more than 200 hours. A transparent case back and sapphire dial enhance the details, while hands without luminescent material distinguish the functions.
The specimen visible in the photo, Audemars Piguet Royal Oak Perpetual Calendar ref. 25829OR, is a true masterpiece in perfect condition. Equal to reference 25820 but in a fully "skeletonized" version, reference 25829 was produced during the same period (1996-2013) as the "regular" model. Made in 371 pieces in steel, 102 pieces in yellow gold, 174 in rose gold, 156 in platinum, 25 in steel and platinum plus another made in 2006, 15 pieces in tantalum and yellow gold, 16 in tantalum and platinum, and 16 in tantalum and rose gold.
The model seen in the photo, with case and bracelet in rose gold (although it would be more correct to use the official definition "Red Gold"), is in an extraordinary state of preservation: particularly appreciable is the contrast of colors between the exterior and the sophisticated mechanics, which, especially in its back, offers a beautiful example of the skeletonization combined with the guilloche engraving of the steel. Its functions are: perpetual calendar: day, date, month, phase and age of the moon. Its registration date is July 7, 2007, while the official extract shows the date of January 15, 2019.
It took the best craftsmen more than 200 hours to openwork and engrave a Caliber 2120/2802_SQ. When you consider that not even four hundred Model 25829 watches were produced in 17 years, along with other openworked watches, it is easy to see that the Audemars Piguet workshop led by Régis Meylan had a lot to do.
The enthusiast will especially admire the extreme refinement of the oscillating weight, the openwork and engraving of the bridges, or the perfect chamfering of all steel parts. To make these elements visible, the case back is transparent for the first time and the dial is made of sapphire. As for the hands, following the example of other perpetual calendar models, they are mostly free of luminescent material and distinguish calendar functions from hour functions.
The Story
In 1984, when Audemars Piguet first fitted the caliber 2120/2800 to the Royal Oak model, the house's master watchmakers combined two legendary features: the exclusive design created by Gérald Genta launched in 1972 and the world's thinnest self-winding perpetual calendar with central rotor, first introduced in 1978.
During the decade under review, 1630 Royal Oak Perpetual Calendar watches are put into production: of the 10 models, six references are produced in less than five pieces. The initial version, Reference 5554, was made in only 279 pieces, most with a yellow gold case (279 pieces), then steel (49 pieces) and only one in platinum. Its production began in 1984 and ended in 1993, while marketing began in 1985 and ended in 1993.
We begin the story of the Perpetual Calendar mounted on the Royal Oak with the versions without the leap year indicator. There are 1,630 pieces, produced roughly between 1984 and 1993, with references: 5554 (25554), 25636, 25654, 25624 and 25651.
Let's start with the progenitor: the reference 5402ST Royal Oak serial A was 7.2 mm thick with an extra-thin automatic movement of only 3.05 mm. In comparison, the Royal Oak Perpetual Calendar reference 5554 measured 9.3 mm thick with a 3.95 mm movement (the Patek Philippe perpetual in reference 3448 measured 11 millimeters) . This is an important achievement, which hardly alters the very physicality of the watch, which remains enjoyable also and above all thanks to the fortunately unchanged diameter of only 39 millimeters
The first reference 5554 was produced in only 279 pieces, 229 in yellow gold, 49 in steel, and only one in platinum. The dials were plain, without the tapisserie decoration, with non-bright colors.
The Great Beauty
The second series is considered by collectors and enthusiasts worldwide to be one of the absolute finest timepieces ever made: we are talking about 25636 with a skeletonized dial. All Royal Oak skeletonized perpetual calendars without a leap year indicator fall under this reference, while those displaying the leap year have the reference 25829. It should be remembered that skeletonizing in that era was basically done by hand and was the preserve of only the most skilled watchmakers, who knew how much material to "remove" without touching the functionality and mechanical strength of the movement. 264 pieces of this reference were made: 126 in yellow gold, 52 in steel, 49 in two-tone, 34 in platinum and 3 in rose gold.
The "theoretical" second series of the perpetual calendar, made from 1995 to 2015, features the return of the leap year indicator. The first reference 25810.OR.01 in rose gold with caliber 2120/2802 movement sees the light of day to coincide with Audemars Piguet's 120th anniversary. The leap year indication is displayed with a small hand coaxial with the month hand in the dial at twelve o'clock. The same typeface was used for its graphic display as that of the second series 5516 watches.
Meanwhile, in 1996 came reference 25686, which did not feature the leap year indication. These are probably the last movements produced with that type, which were going to close the series. It should be highlighted how the Swiss company really ranged in the realization of the dials of this reference: plain, guilloché, enamel, colored mother-of-pearl. There are also many versions of the case, from steel to two-tone platinum and steel, platinum and rose gold, and finally entirely in platinum.
Also in these years, the Royal Oak perpetual calendar indulges in a version dedicated both to the market and to men with particularly small wrists. We are talking about the reference 25800 with a diameter of only 33 millimeters, also offered for the first time in white gold.
The perfect number
We return to our beloved 39 millimeters with the reference 25820 with caliber 2120/2802 movement from 1998. This is an important watch, as it is the first version with a leap year indicator movement (which we recall we first saw on the limited edition 25810) to go into regular production. As many as five dial variants in steel (
smooth silver-plated, white tapisserie, and three different shades of blue with tapisserie), two dial variants in yellow gold, two in platinum (the most prominent with a salmon dial), three in stainless steel with platinum, and one version in tantalum and rose gold, one in tantalum and yellow gold, and one in tantalum and platinum.
The return of the beloved skeleton also occurs in the late 1990s with the reference 25829. Truly many case variants are offered: steel, yellow and pink gold, platinum, tantalum with platinum, pink and yellow gold. Still on the subject of reduced productions, to highlight in 1999 with reference 25930PT we can observe an extraordinary perpetual calendar in platinum with a diamond bezel and skeleton movement.
