Audemars Piguet
Royal Oak 25636PT | perpetual calendar | openwork dial | platinum

Ref. 25636PT.00344PT.01

Regular price

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Audemars Piguet
Royal Oak 25636PT | perpetual calendar | openwork dial | platinum

Ref. 25636PT.00344PT.01

Regular price

This rare, Audemars Piguet Perpetual Calendar Royal Oak Ref. 25636PT is one of the earliest executions of AP’s open-worked Quantième Perpétuel Automatique, housed within a Royal Oak case. Featuring a decoratively-engraved rotor and bracelet stamped by none other than Gay Frères, only 34 examples were made in platinum.

A Perpetual Calendar Royal Oak

It’s been 45 years since the creation of the original Audemars Piguet Royal Oak and this now classic piece, is more popular than ever. First unveiled by Audemars Piguet in the 1970s and designed by Gerald Genta, who incidentally designed the Patek Philippe Nautilus amongst others, the Royal Oak has become a cultural icon due to its distinctive features and its role as a pioneer for high-end luxury sports watches.

The first Royal Oak to feature a perpetual calendar complication was released in 1983, as the reference 5554 (later designated the ref. 25554). Following this, the ref. 25636 was later introduced (seen in this example), as one of the earliest variants to feature a skeletonised dial exposing the under-dial workings. As a result of the watch’s divergent approach, only 264 examples of the ref. 25636 were produced between 1983 and 1993, limited to just 34 in platinum. At the time, the combination of the sporty, Royal Oak case and complicated perpetual calendar movement was an unusual, forward-thinking approach by the brand. In recent years, the Royal Oak Quantième Perpétuel has since been the canvas on which Audemars Piguet have experimented and redefined its perpetual calendars, introducing various unique interpretations. This reference 25636 represents one of the first steps in this ongoing legacy of open-worked, perpetual calendar Royal Oaks.
The Design

This rare, platinum, ref. 25636PT features a transparent dial, with blue indicators, stick hands and blued subsidiary hands. The layout of the dial includes all the traditional indications of a perpetual calendar: day, date, astronomical moon (with graduation for moon age) and month. It features the "Audemars Piguet" signature in small lettering, only found on the earlier examples of the reference 25636, before the brand adopted its modern signature style.

The Royal Oak was originally conceived as a luxury steel watch, yet its design and proportions render wonderfully when executed in precious metals. Usually more susceptible to wear than stainless steel, this 25636PT is well-preserved, retaining its original lines, crisp hallmarks and shape.

At 39mm in diameter, and only 9.3mm thick, the case is a beautiful twist of perspectives and size. It comes with its original bracelet and deployant clasp, featuring the hallmark of famed bracelet maker Gay Frères, who produced the first Oyster bracelets for Rolex, as well as integrated bracelets for the original Nautilus and Royal Oak. Thanks to the slim profile of the case and bracelet, the ref. 25636 hugs the wrist, in a way that is both comfortable, yet distinctively elegant, balancing the weight of the platinum case perfectly.

On the reverse, the outer-case back correctly displays the unique serial number (D-27XX), along with its sequential case number (4X). The ref. 25636PT is housed in a 39mm case (like the 5402 'Jumbo’) - succeeded in 2015 by the latest generation of 41mm perpetual calendars.

The platinum case and bracelet are excellently finished, with angular, beveled and polished edges - striking a balance between utilitarian function and elegant design. The polished screws, bezel and case edges fantastically-contrast with the brushed surface of the case and bracelet. The watch features its original unsigned crown, white gold clasp and clasp cover with "AP" signature.

The Movement

This Royal Oak Quantième Perpétuel is powered by the AP caliber 2120/2800, derived from Jaeger-LeCoultre’s legendary ultra-thin JLC 920 calibre movement. The caliber 2120 was an initial project of Jaeger LeCoultre in 1967, funded and contributed by Audemars Piguet, and famous for its adoption by Audemars Piguet, Patek Philippe and Vacheron Constantin.

The ultra-thin automatic 2120/2800 calibre features 38 working jewels, Gyromax balance and four ruby wheels to support the full-diameter rotor, which runs on a beryllium rail for stability. The AP calibre 2120 remains the thinnest full-rotor self-winding movement in the world, considered by many as one of the most technically refined wrist-watch movements ever made.

The Set

This Royal Oak 25636PT is accompanied by its original box, outer box and stamped Guarantee.

Brand: Audemars Piguet
Model: Royal Oak Ref. 25636PT Quantième Perpétuel
Movement: mechanical automatic AP Calibre 2120/2800
Functions: perpetual calendar: month, date, day, moon-phase; hours, minutes
Features: open-worked dial, engraved rotor
Case: 39 mm platinum
Crystal: sapphire front, display back
Bracelet: platinum Gay Frères-stamped bracelet and AP-stamped white gold clasp
Year: 1992 (sold)
Box & papers: original box, outer box, stamped Guarantee
This Audemars Piguet Quantième Perpétuel 25636PT comes with its original Guarantee, which confirms the case, movement and serial numbers. The case and bracelet are excellently finished, with angular, beveled, polished and granular surfaces. The case shows signs of wear, though retains its original shape and is preserved in excellent overall condition. All hallmarks are sharply defined, with minimal bracelet stretch. The 2120/2802 calibre movement of this 25636PT comes with a two-year warranty from A Collected Man.


All of our pre-owned watches have undergone thorough mechanical inspections, including being ultrasonically cleaned, serviced and resealed if appropriate and tested for at least four days, to ensure they meet our highest timekeeping standards. Our pre-owned and vintage watches, unless stated otherwise, are covered by a full or a limited twenty-four month warranty. For example, due to their age, some vintage watches should not be subjected to the same conditions as when they were new. Please see our Terms & Conditions for further information. 

All of our new watches are covered by the warranty from the original manufacturer. Please contact us for further information.

During a period of adjustment, we are unable to ship watches to the EU. We continue to offer express delivery to all other countries.

If ordering from the UK before 1 PM, your watch will be sent the same working day. The courier will depend on the value of the watch, with all watches delivered the next working day.

If ordering from outside Europe, delivery will depend on choice of courier and destination. 

Please note that pre-owned goods (in the United Kingdom) are subject to a marginal rate of VAT, which can not be reclaimed. For further information, please see here.

You can cancel your order without giving any reason, within 14 days from the day the watch has been delivered to you.

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