Quick answer
A replica Da Vinci moon phase copies the IWC Da Vinci Automatic Moon Phase 36, reference IW4593. That watch has a 36 mm case and a lunar disc at 6 o'clock, driven by IWC calibre 35800. Most replicas run a quartz module or a low-cost automatic with a moon disc added to the front plate. On many of those builds the disc advances twice in 24 hours, so the phase falls out of step with the sky in under a week.
What a moon phase actually does
The synodic month, the gap between two new moons, is 29.53059 days. A standard moon disc carries 59 teeth. A finger on the hour wheel pushes one tooth each 24 hours. Fifty-nine half-days equal 29.5 days. The leftover 0.03059 day per cycle accumulates. A 59-tooth disc reads one day ahead of the sky after roughly 2.7 years. Owners reset it with a pusher or the crown.
IWC states the moon phase in its perpetual calendar deviates by one day in 577.5 years. That construction uses a geared train, not a single stepping finger.
Da Vinci references that replicas target
- Da Vinci Perpetual Calendar, ref. IW3750, released 1985. Kurt Klaus module. Four-digit year display. Moon phase linked to the calendar.
- Da Vinci Automatic Moon Phase 36, ref. IW4593, released 2017. 36 mm case. Calibre 35800. Moon aperture at 6 o'clock. Date window at 3 o'clock.
- Da Vinci Automatic Moon Phase 36 in red gold, same 36 mm case, different dial color.
Case diameter is the first number to confirm. A 36 mm case sits small on a 7-inch wrist. Replica listings that quote 40 mm or 41 mm describe a different watch.
What replicas get right
Current replicas copy the case profile, the lug shape, the sapphire crystal dome, and the printed dial text. Some use a 24-hour disc with a painted moon and stars. Some use a real 59-tooth disc and a correct ratio to the hour wheel.
What replicas get wrong
- Disc speed. A disc tied to the hour hand moves twice per day instead of once.
- Disc print. Moon craters lose detail at the edges. Stars sit off-center in the aperture.
- Font. The IWC logo, the date numerals, and the minute track spacing differ from the original.
- Movement. Quartz versions have no seconds sweep. Automatic versions often run 21,600 vph instead of 28,800 vph.
- Case finishing. Polished bevels on the lugs are shallow. Brushed surfaces show a coarser grain.
- Water resistance. A replica case back gasket is not rated. Do not swim with one.
How to test a moon phase disc in a store or from photos
- Set the watch to a known date and note the disc position against the aperture edge.
- Note the reading again after 24 hours. One tooth of movement equals half a lunar day.
- Note it again after 48 hours. Three advances in 48 hours means the disc runs off a 24-hour wheel, not a 24-hour finger.
- Ask for a photo of the moon aperture at the same clock time on two days.
Price signals
A genuine IWC Da Vinci Automatic Moon Phase 36 in steel trades in the mid four figures on the secondary market. Replica pricing sits far below that. Listings that quote the same reference number as an original and a low price describe a copy.
Legal note
IWC does not make or authorize replica watches. Counterfeit goods cannot be imported into the United States under 19 U.S.C. 1526, and trafficking carries penalties under 18 U.S.C. 2320. Customs and Border Protection can seize shipments and destroy them.