Short Answer
A fake Audemars Piguet Royal Oak Perpetual 25659 is judged on four things, in this order: the dial and subdial layout, the case and bracelet finishing, the weight and thickness, and the movement seen through the back. Dial layout is the fastest test. If the day, date, month, leap-year and moonphase elements are placed or printed wrong, the rest of the watch cannot save it.
Before You Start
- A 10x loupe and a bright light you can angle.
- Digital calipers and a kitchen scale that reads to 1 g.
- Three reference photos of a genuine 25659 at the same angles: dial straight on, side profile at eye level, caseback flat.
- The catalog dimensions for the exact variant you are comparing against, because the vintage Royal Oak Perpetual Calendar line was built in small series with different cases and dials.
Step by Step
- Set the reference photos first. Put the genuine images on a second screen or a printout before you handle the watch, so every check is a direct side-by-side comparison.
- Measure the case with calipers. Record width across the bezel at 3 and 9 o'clock, width including the crown, and total thickness. Compare those numbers with the catalog figures for the variant, not with the seller's listing text.
- Weigh the watch. A gold or platinum case carries weight for its size. If a watch sold as gold weighs close to a steel watch of the same diameter, the case is plated brass or plated steel.
- Count the dial functions. A perpetual calendar shows day, date, month, leap year, a moonphase and a 24-hour or day/night indicator. Count the subdials, apertures and hands against the reference photo.
- Check the subdial rings against the hand pivots. Look at each subdial head on. The printed ring should sit centered on its hand pivot with even spacing on all sides.
- Read the printed text under the loupe. Compare stroke weight and letter shape on the brand name, the model line and the Swiss mark at the bottom of the dial.
- Inspect the moonphase disc. The disc should carry a printed moon and star field with clean edges at the aperture, and it should move when you advance the calendar.
- Study the eight bezel screws. Each screw should sit in a countersunk flat with a crisp hex head and a clean slot cut through it.
- Trace the bracelet taper and link finish. Link bevels, brushing direction and the polish line on the case should change at the same points as the reference.
- Read the caseback engraving. Check reference number, case number, metal hallmarks and logo. The cuts should have sharp walls and even depth, not shallow scratches filled with paint.
- Ask for movement photos or open the back. Compare rotor shape, engraving depth, jewel count and bridge finish with photos of the genuine caliber.
- Reconcile the price with the grade. Matching dial layout, working calendar and finished movement cost money to produce, so the asking price should sit in the band for that grade.
Red Flags
- Subdials that do not advance when the calendar pushers are used.
- A moon disc with a flat or dotted image sitting off center in the aperture.
- Bezel screws with flat tops or plain slots instead of hex heads.
- Engraving that sits on the surface of the metal.
- A case sold as gold that pulls on a magnet.
- A seller who will not send movement photos.
Setting a Perpetual Calendar After Delivery
- Set the day and date to the day before your target date.
- Advance the watch past midnight so the calendar jumps once.
- Push the correctors forward to the current date, one step at a time.
- Set the month and the leap-year pointer to the current year in the four-year cycle.
- Set the time last, turning the crown forward. Keep the correctors away from the change cycle, a few hours either side of midnight.
What Good First Copies Get Right
A strong 25659 first copy shares a short list of traits: case proportions that match the variant, the right number of subdials in the right places, a moonphase that advances, a bracelet whose taper follows the case, and a movement with a decorated rotor and a module that actually sets the calendar. Buyers who check those five points before they pay get fewer surprises than buyers who judge from photos alone.