If you are shopping for a fake Rendez-Vous with the moon at the back, the top pick is a stainless-steel automatic with a real 59-tooth moon disc and a sapphire exhibition caseback. That trio separates a watch you can wear daily from a costume piece that sits in a drawer. The criteria used here: movement type, whether the moon is a working geartrain or a printed plate, caseback finishing and engraving, and case diameter against your wrist.

What "back of the moon" means here

Rendez-Vous is a Jaeger-LeCoultre collection, and the moon display on those pieces reads the lunar month through an aperture in the dial. Buyers use "back of the moon" for two different things. First, the geartrain that turns the moon disc, which sits behind the dial and becomes visible through an exhibition caseback. Second, a caseback that has been engraved or stamped with a moon motif, often surrounded by a star field. Both readings matter on a replica, because the reverse of the watch is where shortcuts surface first.

How a moon phase works, and why the back matters

A classic moon phase runs a disc with 59 teeth, which represents two lunar months of roughly 29.5 days each. A finger on the hour wheel pushes that disc forward one step per day. Because 59 teeth approximate the real 29.53 day cycle, the display drifts by about one day every two to three years, which is why most owners never bother correcting it. Where the movement is visible, you can watch the disc index forward and confirm the complication is mechanical rather than decorative. On a sealed caseback you cannot, which is the practical argument for sapphire.

The three tiers of replica you will encounter

Tier 1: quartz with a printed moon

  • Pros: lowest cost, no winding, keeps time well.
  • Cons: the moon disc is printed on a flat plate and does not move, the caseback is plain steel with a stamped logo, and the seconds hand ticks.
  • Use case: a display piece or a gift where nobody inspects the reverse.

Tier 2: automatic with a moon module

  • Pros: working moon disc, smooth sweep, exhibition caseback shows the rotor, and the module adds real depth to the movement side.
  • Cons: setting the moon takes care, recessed correctors can be stiff, and servicing is impractical, so replacement is the usual path.
  • Use case: everyday wear for someone who wants the complication to work.

Tier 3: decorated build with an exhibition back

  • Pros: perlage, blued screws, engraved rotor, and a moon disc with a painted or applied moon face. The back becomes a talking point.
  • Cons: highest cost of the three, finishing quality shifts between batches, and decoration hides nothing if the gear train is thin.
  • Use case: collectors who care about the reverse view as much as the dial.

What to inspect on the caseback

Start with the crystal. Sapphire has a cool, hard feel and a sharp reflection, while mineral glass looks softer and picks up fine scratches over months. Check engraving depth under raking light: crisp edges and even depth suggest a proper stamp or laser cut, while shallow, wavy lettering suggests a cheap die. Look at the rotor. A half-decorated rotor with machining marks under the engraving is common on budget automatics. Give the watch a gentle shake and watch the rotor turn. It should spin with light effort and stop without grinding.

Case size and wear

Rendez-Vous style cases sit in a dressier range, often under 40 mm, with a slim profile and sometimes a set bezel or stone markers on the ladies' versions. If your wrist measures under about 6.5 inches around, a 36 mm to 38 mm case reads better than a 42 mm. Lug-to-lug matters more than diameter, since anything past 46 mm will overhang. A moon display adds visual weight to the lower dial, so a clean index layout keeps the face balanced.

Before you buy: a short checklist

  1. Confirm the movement type in writing rather than from a listing photo.
  2. Ask for a video of the moon disc advancing or the rotor spinning.
  3. Ask for caseback photos under direct light, straight on and at an angle.
  4. Measure your wrist and compare against the listed lug-to-lug, not the diameter.
  5. Treat water resistance claims with care. A push-pull crown and a decorated exhibition back rarely support more than splash resistance.

Recommendation

For most buyers the second tier is the right answer. A working automatic moon phase with a sapphire caseback gives you the complication and the reverse view without the premium that decorated builds command. Step up only if the back of the watch is the part you will show people. Step down to quartz only if the moon display is scenery and you want the lowest risk purchase.