A fake Da Vinci moon phase watch is worth owning when its moon disc is driven by a lunar gear train and not by the date wheel. That single detail decides the tier and the price. The top pick for most buyers is an automatic build based on a Valjoux 7751 or a custom moon phase module, because the disc advances on a cycle close to the real 29.53 day synodic month. Below that level you are buying a calendar dial with a moon painted on it, and the phase will be wrong within a couple of months.
This guide sorts the replica market into four tiers, then walks through the four checks that matter: the moon disc drive, the setting system, the case and dial work, and movement service. Each section closes with the buyer it fits.
What a Da Vinci Moon Phase Replica Sets Out to Copy
The Da Vinci line gives copy makers two different targets. One is a moon phase calendar watch with a single lunar subdial. The other is a perpetual calendar chronograph, where the moon phase shares the dial with day, date, month, and a leap year display. The second target is the hard one, because a true perpetual calendar has to track 28, 30, and 31 day months and add February 29 on its own.
Most copies take the dial of the perpetual calendar and the mechanics of a simple calendar watch. Photos look correct. The moon moves. But it moves with the calendar, so the phase drifts. Decide which target you want before you compare anything else.
Tier 1: Quartz Moon Phase Copies
Quartz builds are the entry point. The case and dial copy the shape, and the subdial near six o'clock turns, which is often all the product photos show.
- Pros: Low cost, accurate timekeeping, slim case, and no winding or setting routine.
- Pros: Easy to replace if it fails, with no service cost to weigh.
- Cons: The moon subdial is usually a 24 hour day and night disc, or a disc that steps once per day with the date. It does not track a lunar month.
- Cons: Ticking seconds hand, plated case, flat dial printing, and a water resistance rating that was never tested.
Best for: A costume piece worn a few times a month, where the dial reads well from arm's length and nobody inspects the moon phase against the sky.
Tier 2: Automatic Copies on a 7750 Base
The 7750 chronograph base has no moon phase train. Makers add a module on top of the movement, or they simply print a moon on a subdial that is really a running seconds or a 24 hour hand.
- Pros: A real automatic movement with a working chronograph, a sweeping seconds hand, and standard parts inside.
- Pros: Any competent watchmaker can regulate or clean it, which keeps long term cost down.
- Cons: No lunar cycle. The disc either spins once per day or jumps with the date change.
- Cons: Stacked modules add height and add a failure point, so the calendar can stop while the watch still runs.
Best for: The buyer who wants an automatic, serviceable watch with the right silhouette and accepts that the moon phase is decorative.
Tier 3: 7751 and Custom Lunar Module Builds
A 7751 base carries day, date, month, a 24 hour indicator, and a moon phase in one movement. That is the layout the Da Vinci calendar models actually use, and it removes the need for a bolt on module.
- Pros: The moon disc advances about one tooth per day and completes a cycle near 29.5 days, so the phase stays close to correct for years with a small correction later.
- Pros: Correct complication set, proven gear train, and parts that exist outside the replica supply chain.
- Cons: Higher cost, thicker case than the quartz tier, and quality that depends on who assembled the dial and hands.
- Cons: Moon disc artwork varies. Some discs show the wrong number of stars or a moon that faces the wrong way.
Best for: The buyer who wants the complication to work and is willing to pay for a movement that can be serviced and corrected.
Tier 4: Perpetual Calendar Copies
These builds copy the full perpetual calendar dial with four subdials and a leap year window. On the original, the calendar is set through the crown instead of recessed correctors, which is the famous part of the design.
- Pros: The most complete dial, with day, date, month, leap year, moon phase, and often a chronograph.
- Pros: The best examples set several functions from the crown, which matches how the real watch is operated.
- Cons: The leap year and month logic is frequently a display only. The watch cannot advance from February 28 to March 1 without help.
- Cons: Extra corrector pushers on the case side are a giveaway, since the original does not need them.
Best for: A collector who wants the dial presence of the perpetual calendar and treats the calendar functions as display rather than daily use.
Check 1: How the Moon Disc Is Driven
Set the watch to a known date, note the moon phase, and advance the date through 30 days. A lunar drive moves the disc by one small step per day. A calendar drive jumps the disc a full step at midnight or spins it at twice the speed. You can also look at the disc through the subdial opening and count teeth on the edge if the aperture is wide enough.
- Pros of a lunar drive: Phase matches a lunar calendar, and the disc moves in small daily increments.
- Cons of a calendar drive: Phase is meaningless within weeks, and the disc often shows a hard jump that looks nothing like the real thing.
Best for: Anyone who plans to wear the watch on a rotation and glance at the moon phase as a real reading.
Check 2: Setting System and Calendar Logic
The original Da Vinci perpetual calendar sets its calendar through the crown. A copy that needs a pin tool in four recessed correctors is telling you the mechanism is a set of independent gears with no shared logic.
- Pros: Crown setting, or a mix of crown setting and one corrector, points to a build that copied the real gear train.
- Cons: Four correctors, or pushers hidden on the case flank, usually mean the month and leap year wheels do not talk to each other.
Best for: Buyers who will actually set and wear the watch often, since crown setting is faster and less likely to damage a seal.
Check 3: Case, Crystal, Dial, and Strap
Finishing separates a clean build from a rushed one. Look at the lug bevels, the crown profile, and the gap between the dial and the rehaut. Sapphire with a proper anti reflective coat should look almost invisible at an angle, while mineral glass shows a blue or green haze.
- Pros: Sharp polished and brushed transitions, a signed crown, and printed markers that sit flat under a loupe.
- Cons: Soft edges, a domed crystal with heavy tint, painted subdial rings, and a strap that smells of solvent.
Best for: Wearers who spend time near people who know the model, since case and dial errors are what get noticed first.
Check 4: Movement Parts and Service
Ask what happens when the watch stops. A 7750 or 7751 based build has a path forward, because the base calibre is common. A custom clone with no parts supply becomes a paperweight the first time a pivots breaks.
- Pros: Standard base calibre, available gaskets, and a watchmaker who will touch it.
- Cons: Sealed modules, glued casebacks, and a maker who will not sell parts.
Best for: Long term owners who want the watch running in five years, not just on delivery day.
Red Flags at the Handoff
- The listing shows a moon phase photo but the movement description never names the base calibre.
- The moon disc moves a full step at midnight instead of a small daily advance.
- The case has corrector pushers that the reference model does not use.
- Water resistance is quoted as a number with no test, and the caseback gasket is dry on arrival.
- The seller shows the same photos on several listings under different names.
Recommendation by Use Case
- Occasional dress wear: Tier 1 or Tier 2. You want the dial and the profile, and the moon phase is a look, not a function.
- Daily rotation with a real complication: Tier 3 on a 7751 base. The lunar drive, serviceable parts, and correct subdial set justify the extra spend.
- Collection piece: Tier 4, but only if the calendar advances on its own through short months and the setting is done from the crown.
Judge the moon disc first, then the setting system, then the case. A fake Da Vinci moon phase that gets the first two right will still read as a serious watch years later. One that only gets the dial right will not.