Watch reference numbers explained: Patek, AP, RM, F.P. Journe

Reference number or serial number: what is the difference?

A reference is shared by every watch made to one specification. Patek Philippe’s Certificate of Origin identifies a watch by its ‘movement, case and reference numbers’ — three different things.^[5]

The case number and movement number belong to one watch only. Patek Philippe engraves the case number ‘on the inside of the case back’ and the movement number ‘in the movement’.^[4] Audemars Piguet states that ‘Each Audemars Piguet watch bears two engraved numbers’, one on the movement and one on the case.^[1]

How Audemars Piguet references work

Audemars Piguet’s references began with four digits. In the mid-1980s they moved to five, and older references were renamed: ‘5402 became 25402’.^[1] AP calls this five-digit base the ‘root reference’.^[1]

Since the 1970s, the reference has also shown the case’s main material.^[1] AP’s own key includes ST for steel, BA for yellow gold, BC for white gold, OR for pink gold, PT for platinum and CE for black ceramic.^[1]

AP’s heritage team breaks down its example 15202ST.OO.944.ST.3 like this:^[1]

• 15202: the root reference
• ST: steel case
• OO: the finishing, ‘standard decoration’
• 944: the bracelet
• ST: the bracelet material, steel
• 3: the dial, blue

The Royal Oak Selfwinding 15510ST.OO.1320ST.06 is a 41 mm steel watch with a ‘Bleu Nuit, Nuage 50’ dial on AP’s own model page.^[6] AP’s own model pages show the last two digits changing with the dial, as HYPA’s pages do. The 15510ST.OO.1320ST.07 is black, the 15510ST.OO.1320ST.08 silver-toned, the 15510ST.OO.1320ST.09 khaki green and the 15510ST.OO.1320ST.10 grey.^{[7][8][9][10]}

Same case, same bracelet, same 41 mm: on a Royal Oak, the last two digits can be the whole difference.

HYPA lists its Audemars Piguet watches under their full references. The Royal Oak buying guide covers the other checks before you buy.

AP case numbers and the Royal Oak number

AP’s movement numbers now run as two letters and four digits. For almost 75 years the case number was the same as the movement number.^[1] AP made both numbers alphanumeric and ‘randomly computer-generated in order to combat counterfeiting’.^[11]

Royal Oaks from the 5402 onwards also carried a separate ‘Royal Oak number’ on the case back for the owner. It disappeared in the second half of the 2010s.^[11]

How Patek Philippe references work

Patek Philippe writes the case material as a letter, ‘summarized by the first letter of its French designation’.^[2] Patek’s own examples are 5726/1A-014 for steel (acier), 5231J-001 for yellow gold (jaune), 6300G-010 for white gold (gris), 5968R-001 for rose gold and 5373P-001 for platinum.^[2] Patek Philippe also sets a diamond at 6 o’clock in every platinum case.^[2]

So the Nautilus 5811/1G-001 is a white-gold watch: Patek lists its case and bracelet as white gold.^[12] HYPA lists the Nautilus 5990/1R-001 in rose gold.

Patek Philippe’s page on cases explains only the material letter, so compare the full reference letter for letter.^[2] For the other checks, see how to buy a pre-owned Patek Philippe in Australia, or browse HYPA’s Patek Philippe watches.

Where Patek puts the numbers

Patek Philippe says only its authorised retailers or service centres should remove the case back to read the movement number.^[4]

The Certificate of Origin is valid only if it is ‘dated, signed by an Authorized Patek Philippe Retailer, and completed with your name’.^[13] Patek states that it ‘can unfortunately never be re-issued’.^[4]

How Vacheron Constantin references work

A Vacheron Constantin reference reads like 5520V/210A-B481, shown on its model page for a 42.5 mm steel Overseas Chronograph.^[14] The 4520V/210R-B967 is a 41 mm pink-gold Overseas Self-Winding.^[15] Its model pages show the full reference without explaining its parts.

Vacheron Constantin’s warranty excludes ‘watches with the serial number or any other identification mark removed or altered’.^[16] Since 2019 its Digital Passport has held ‘key information about the timepiece, including its ownership history’.^[16]

HYPA lists the Overseas Chronograph 5520V/210A-B481 and the Overseas Self-Winding 4520V/210R-B967 under these exact references, with the rest of its Vacheron Constantin watches.

Richard Mille, F.P. Journe and Greubel Forsey: model names and numbers

Richard Mille names each model ‘RM’ plus a number. Its first watch was the RM 001 Tourbillon, introduced in 2001 in an initial series of 17 watches.^[17] Later numbers can replace earlier ones: the RM 011 ‘retired at the height of its glory to make way for the RM 11-03 Automatic Flyback Chronograph’.^[18]

HYPA lists the RM 11-03 Ti and the RM 11-03 Black Carbon TPT® as separate watches. Richard Mille’s activation warranty card ‘is paired with the serial number of the watch’.^[19] Before you buy, see how to buy a pre-owned Richard Mille in Australia and HYPA’s Richard Mille watches.

F.P. Journe gives each model a name and a short code, such as ‘Chronomètre Bleu - Ref. CB’.^[3] Some codes cover more than one model: the Chronomètre Souverain and the Chronomètre Souverain Black Label are both ‘Ref. CS’.^[3] F.P. Journe engraves each chronometer’s ‘individual number on the case-back’.^[20] It can issue a certificate of authenticity for a watch first sold more than 5 years before the request.^[21]

Greubel Forsey shows model names, not reference codes, on its model pages.^[22] It states edition sizes instead: the Balancier QM is ‘Limited to 33 timepieces in a 39.6 mm white gold case’.^[22] HYPA lists its F.P. Journe watches by name and code, and its Greubel Forsey watches by model name.

How to find out what year a watch was made

The movement number alone does not date a watch. Audemars Piguet says the movement number ‘is not a sufficient means of determining the exact date of a watch’.^[1] Three brands answer from their own archives:

• Patek Philippe: the Extract from the Archives is ‘a partial transcript regarding a particular timepiece from our Archives’, for a watch ‘first sold at least ten years ago’. It costs 500 Swiss francs.^[5][23]
• Audemars Piguet: the Extract from the archives confirms the numbers ‘appear in our records, but does not warranty the authenticity of the watch’. The Certificate of Authenticity requires an examination in Le Brassus. AP’s Geneva boutique price list shows CHF 500 for the extract and CHF 2,500 for the certificate, excluding taxes.^[24][25]
• Vacheron Constantin: the Extract from the Archives gives ‘the date of manufacture and sale’. The Certificate of Authenticity ‘indicates the year of manufacture’ after the Heritage Department examines the watch.^[26]

For the papers and checks that come with a watch from HYPA, see what you receive when you buy from HYPA.

What a dealer records when you sell a watch in Victoria

A registered Victorian second-hand dealer must require every seller ‘to produce evidence as to the person’s identity’.^[27] For each transaction it must record ‘an accurate description of the goods received, including a description of any identifying mark or label on the goods’.^[28]

The dealer must also keep second-hand goods ‘in the form in which they were received’ for 7 days.^[27] If you plan to sell, see how HYPA values a watch you want to sell and the Sell or trade page.