A replica Audemars Piguet Royal Oak Perpetual 25659 is a copy of a vintage Royal Oak perpetual calendar, the octagonal Gerald Genta case paired with a four-register calendar dial and a moonphase at 6 o'clock. The strongest examples get the case profile, dial tapisserie texture and subdial positions close to the original. The weakest ones miss the case thickness, the moonphase color and the bracelet taper. If you want one that reads correctly on the wrist, judge the case and bracelet first, the dial second, and the movement last.
What this reference represents
Vintage Royal Oak perpetual calendars from the 1980s and early 1990s were built on a thin automatic base movement with a calendar module stacked on top. That architecture is what gave the watches their slim profile and their very specific dial furniture: four small registers instead of three, and a moonphase disc that sits low and close to the rehaut.
Because so much of the appeal is proportion, a 25659 replica succeeds or fails on geometry rather than decoration. A correct octagonal bezel with eight visible screws, a dial that fills the aperture properly, and a bracelet that flows into the case without a visible step matter more than a stamped logo.
Movement options you will find
- Automatic with a calendar module. The closest match in feel. Look for a smooth sweep and a date change that does not lag.
- Automatic day, date and 24-hour versions. Common in mid-tier builds. The registers move, but the layout sometimes borrows from a different model.
- Quartz or mecha-quartz. Slimmer and cheaper, but the second hand tick gives it away and the moonphase is often printed rather than rotating.
Ask which base movement is inside and whether the moonphase actually advances. A static moon disc is the single most obvious tell on this reference.
Case and bracelet checks
- Bezel screws should sit flush and align vertically against the case flanks.
- Case sides should show a brushed flat and a polished bevel, with a crisp line between them.
- Bracelet links should taper toward the clasp instead of staying a constant width.
- End links should meet the case with minimal gap and no rattle.
- Overall thickness should stay in vintage territory, not swell into modern sports-watch bulk.
Dial and subdial accuracy
On the original layout, day sits at 9 o'clock, date at 3, month and leap year at 12, and the moonphase at 6. Text size, font weight and hand shape all follow that arrangement. On a replica, check that:
- The month register is not replaced by a plain 24-hour indicator.
- Applied hour markers are polished and sit level, with no glue visible at the base.
- The moonphase aperture is not sitting high or crowding the 6 o'clock marker.
- The dial texture is consistent from the center outward, not blurry at the edges.
Size and wearability
Vintage Royal Oak perpetual calendars wear smaller than modern Royal Oaks, and that is part of the charm. On an average wrist the case sits close and the bracelet drapes rather than standing off the skin. If a replica feels top-heavy or flips over on the wrist, the link geometry is wrong, no matter how good the dial looks in photos.
A short pre-purchase checklist
- Request close-up photos of the bezel screws and the case flank lines.
- Ask for a video of the moonphase and date advancing.
- Confirm the case diameter and thickness in millimeters.
- Check that spare links are available for your wrist size.
- Read the return and service terms before paying.
Owning and caring for it
Treat any replica as a fashion watch. Keep it away from steam and hot water, wipe the case with a soft cloth after wear, and have the gaskets checked before trusting it near a pool. A perpetual calendar display is delicate in any watch, so set the day, date and month only through the correct pushers or crown positions and avoid changing them near midnight. Store it flat in a dry place, and if the moonphase drifts, expect a watchmaker to realign the disc rather than a simple reset.
Buy the version that gets the proportions right. Everything else can be lived with.