Quick answer
A replica Rendez-Vous Moonphase copies the Jaeger-LeCoultre Rendez-Vous Moon, a women's watch with a lunar disc set at 6 o'clock. The real one comes in 34mm and 36mm cases, runs on an automatic movement, and pairs a textured dial with either a plain steel bezel or a diamond-set one. Replicas follow that same recipe, but they split into two families: quartz versions with a 24-hour day/night disc, and versions with a real 29.5-day moonphase.
That split is the whole ballgame. Case finish, strap, and printing can all be fixed or replaced. A fake moonphase cannot.
Moonphase or day/night: the check that decides everything
A real moonphase tracks the synodic month, about 29 days, 12 hours, 44 minutes. The mechanism is a wheel with 135 teeth driven once a day, which is why the moon drifts only one day off true in roughly two and a half years.
A day/night disc looks nearly identical in a photo and turns once every 24 hours. Same moon graphic, same star field, same aperture. The only way to tell is time.
- Take two photos of the aperture 24 hours apart. If the moon has crossed a quarter of the window, it is a day/night disc.
- Ask the seller for a 48-hour clip. Most will not have one, and that silence is worth noting.
- A real moonphase moves a sliver a day. You should barely see the change in one sitting.
Quartz moonphase modules exist and work correctly. Miyota and Seiko both make them, so a quartz replica is not automatically a fake moonphase. Judge the disc, not the power source.
Sizes and proportions
The genuine Rendez-Vous Moon Medium is 36mm across, and the smaller Rendez-Vous Moon is 34mm. Both sit thin for a moonphase, well under 10mm on most references. Lug width runs about 17mm on the 34 and 18mm on the 36.
Replicas usually get the diameter right and the thickness wrong. A moonphase module stacked on a base movement adds depth, so a copy measuring 11mm or 12mm is normal for the price and will sit higher on the wrist than the original. If an ad claims 8mm on a $200 automatic moonphase, the number is invented.
Check the lugs too. The original has soft, curved lugs that flow into a croc-grain strap. Replicas often use a squarer lug shape borrowed from a generic case, which shows from the side.
Movement: what you are actually paying for
Three tiers show up in this market.
- Quartz day/night, roughly $80 to $150. Mineral glass, printed dial, disc that turns daily.
- Quartz moonphase, roughly $150 to $300. Correct 29.5-day gearing, often sapphire, better dial texture.
- Automatic with a moonphase module, $300 and up. Chinese base movements (Seagull and Hangzhou families are common) with an add-on moon disc. Sweeping seconds, real lunar cycle, more service risk.
Automatic moonphase modules are the fussiest part of the watch. Set them gently, never force the corrector, and do not hand-wind more than a few turns. If the moon disc stops advancing, the module is usually the culprit, not the base movement.
Dial, bezel, and details people miss
Look at the moon disc first. On the original it is a photorealistic moon against a star field, set into a ring that matches the dial. Cheap copies print a flat white circle with gray smudges.
Then the bezel, if it has stones. Good setting means even prongs, no gaps, no visible glue, and diamonds that sit at the same height. Poor setting looks cloudy at arm's length, and under a loupe the uneven prongs give it away.
Crystal material comes next. Sapphire or nothing, because mineral glass scratches and gives the dial a dull cast. Then the strap: 17mm or 18mm leather with a signed buckle is a good sign, while a generic 20mm strap crammed onto the lugs is not.
Applied indices, a correct date font, and crisp caseback engraving round out the list. None of those change how it runs, but they decide whether it reads as a $400 replica or a $40 one.
Setting the moonphase without damaging it
Find a known new moon date, count the days since, then advance the disc that many clicks with the corrector. Most moonphase correctors are pushers on the case flank, and some sit recessed and need a pin tool. Never poke the disc through the aperture, and if the watch also shows the date, keep calendar setting away from the midnight window when the change mechanism is engaged.
Once set, leave it alone. A correct moonphase needs resetting about once a year, not every month.
Before you buy: a short checklist
- Case diameter confirmed in millimeters, measured rather than copied from a listing title.
- Sapphire crystal, stated plainly.
- Movement type, quartz or automatic, and whether the moon disc is a true 29.5-day cycle.
- Lug width and strap material.
- Photos of the actual watch, not catalog renders.
- A return window and a stated policy on movement defects.
One honest note
A replica is not a Jaeger-LeCoultre, and nobody who has handled both will confuse them. Counterfeit watches can also be seized at import in the US, and selling one as genuine is fraud. Buy with clear eyes: you are paying for the look and the lunar display, not for the name on the dial.