A very rare, fine, and distinctive perpetual calendar stainless-steel and yellow gold wristwatch of the famous Swiss watch brand Audemars Piguet, founded in 1875. Reference production period: from 1982 to 1993. Estimated production year: circa 1987. Stainless steel case, 18k yellow gold bezel, diameter 39mm, 8.25mm thick, solid stainless-steel caseback with the Royal Oak logo, “Quantième Perpétuel Automatique” inscription, case number and watch number in the series engraved, early non-signed (‘flat’) crown. Matt silvered Mk1 dial, calendar counters with a yellow-metal circular brushed outline, Royal Oak Perpetual Calendar early stick hour and minute hands, and a so-called small logo. Self-winding caliber 2120/2800 with an inertial segment in 21k yellow gold, ultra-thin, with a power reserve of up to 40 hours. Functions – indication of time in hours and minutes, perpetual calendar with indicators of date, day of the week, month, and moon phase. Royal Oak bracelet in 18k yellow gold and stainless steel, the stainless steel first-generation Royal Oak double folding clasp.

Lot essay

Reference 25654 (up to 1984–1985 the four-digit reference 5654 was used) is the earliest reference of the Royal Oak Perpetual Calendar produced from 1982 (officially launched in 1984) on the basis of the caliber 2120/2800. In the book “Audemars Piguet 20th century complicated wristwatches”, the brand states that production was launched in 1982, and 800 pieces of Ref. 5654/25654 were issued from 1982 to 1993, with only 72 of those being two-tone in yellow gold and stainless steel (Phillips reports 68 pieces). That’s why only a handful of the two-tone steel and yellow gold 25654SA watches have appeared at auctions. The present C-series example with a beautiful Mark 1 matt silvered dial, yellow-metal brushed outlines of the counters and no leap-year indication has a distinctive two-tone appearance, becoming hugely popular in the 1980s to the mid-1990s. Retailing on average at about twice the price of a stainless-steel perpetual calendar watch, the two-tone, mainly steel and gold versions of the Royal Oak Perpetual Calendar were introduced as a response to the fashion for such kind of design. The distinctive 1980s vintage look of two-tone Royal Oak Perpetual Calendars attracts modern collectors as a signature timepiece of that epoch and due to the very rare perpetual calendar version becoming ever harder to obtain.

The characteristic feature of this watch is its caliber 2120/2800 – the first Audemars Piguet automatic perpetual calendar in series production, and the second automatic perpetual calendar caliber ever produced. The small thickness of the movement made it possible to produce remarkably thin and elegant watches, which is especially significant given the complexity of the function of the perpetual calendar itself. Caliber 2120/2800 is the first version of such a movement by Audemars Piguet; it differs from subsequent versions in that it was not equipped with a leap year indicator, although it was Audemars Piguet who, in the 1950s, had invented this function for calendar wristwatches.

The present reference is the earliest perpetual calendar reference in the Royal Oak collection, further emphasized by the rare two-tone execution.

The Royal Oak Perpetual Calendar Ref. 5554/25554 watches were produced from 1983 (officially introduced in 1984). Their production was followed by the present Ref. 5654/25654, which featured a slightly thicker case (8.25mm vs 7.5mm for the Ref. 5554/25554) to optimize the design for waterproofness. The dial of the present example with its characteristic small lettering of the logo is a feature of the first-generation dials (Mark 1) used by Audemars Piguet until 1993.

The present reference is powered by an ultra-thin self-winding caliber 2120/2800. With a thickness of 3.95mm, it remained the thinnest perpetual calendar movement with a central rotor of an automatic winding system until 2018. The movement is based on a self-winding movement-blank supplied by Jaeger-LeCoultre, while the calendar module is based on a kit from the Dubois Dépraz factory. Both are long-term partners and suppliers of Audemars Piguet.

Reasons to bid

The Royal Oak Perpetual Calendar Ref. 25654SA.OO.0944SA.01 Two-tone C-series would be an excellent purchase for the collector who desires a distinctive, very rare perpetual calendar wristwatch from a world-renowned traditional watch brand, one of the undisputed leaders in the haute horlogerie watch market. The present reference is the earliest perpetual calendar reference in the Royal Oak collection, with which it began the use of complication calibers. Ref. 25654SA is a classic collector’s item that communicates a certain era in the development of the Royal Oak collection – from 1982 to 1993, when the classic leap year indicator was absent on the perpetual calendar dial – a feature of the time – further emphasized by the rare two-tone execution. For the collector, undoubtedly the most interesting feature of this watch will be the matte ‘non-tapiserrie’ Mark 1 silvered dial, with the so-called ‘small logo’, characteristic for the production of the early period. Ref. 25654SA extremely rarely appears at auctions since the total number of pieces produced was limited, which undoubtedly increases the attractiveness of the present lot.


Commemorating the 50th anniversary of the legendary Royal Oak, this Ineichen Auctioneers sale offers an unprecedented selection of perpetual calendar watches produced by Audemars Piguet since 1982. Royal Oak Perpetual Calendars, which enjoy the active interest of collectors, represent one of the most valuable, admirable and collectible parts of Royal Oak collection heritage. In addition, the Royal Oak Perpetual Calendar remains relevant as a luxurious daily wearer, enriched with a practical perpetual calendar function and self-winding movement, one of the best in its category. The keen collector should note that also offered for purchase in this sale are other attractive and collectible Royal Oak Perpetual Calendars, including the rarest and most desirable Ref. 25654BA Yellow Gold ‘Tuscan Dial’, superhot Ref. 25820ST ‘Yves Klein’, early Ref. 25654BA C-series ‘Golden Nugget’, stainless-steel Ref. 25829ST Open-worked, Ref. 25636BA Open-worked ‘The First Generation’, Ref. 25829OR Open-worked ‘All-Rose Gold’, Open-worked ‘Platinum Edition’ Ref. 25829PT, and a magnificent pair of extremely rare Royal Oak Perpetual Calendar pocket watches in platinum and rose gold, among others.