Quick answer
A fake Patek Philippe Golden Ellipse 5738 gives itself away in four places: thickness, case profile, dial finish, and movement. The genuine reference measures about 34.5 mm by 39.5 mm with a case close to 6 mm thick, and it runs the caliber 240 micro-rotor automatic. Most fakes run 8 mm to 10 mm thick, use a plain three-hand automatic or a quartz module, and print a flat dial instead of a true sunburst. Measure the thickness first. It is the single fastest test you can run.
What the genuine 5738 actually is
The Golden Ellipse line started in 1968 and is built on the golden ratio of 1.618:1. Reference 5738 arrived in 2018 for the model's 50th anniversary in a platinum case with a blue sunburst dial. It has no date and no seconds hand, so the dial stays clean and the case stays thin.
Case
About 34.5 mm wide and 39.5 mm long, close to 6 mm thick, in 950 platinum. The bezel is narrow, the flanks are flat, and the lugs flow out of the case band with no visible seam. Platinum is dense, so the watch head feels heavy for its size.
Dial and hands
Sunburst blue with a fine radial grain that shifts under light. Thin baton hands, a printed signature, and sharp marker edges. With no seconds hand, the dial never looks busy.
Movement
Caliber 240: an ultra-thin automatic at about 2.53 mm with an off-center 22k gold micro-rotor, 27 jewels, and about 48 hours of power reserve. The sapphire caseback shows Geneva stripes, polished bevels, and the Patek Philippe Seal engraving.
Before you inspect
- A 10x loupe or a phone macro lens
- Digital calipers rated to 0.1 mm
- A digital scale rated to 0.1 g
- Catalog photos of the 5738 for side-by-side comparison
- A bright light you can angle across the case
Inspection steps
- Measure the case thickness at the band with calipers. Anything over 7 mm is not a 5738.
- Measure the width and length across the case. The target is about 34.5 mm by 39.5 mm.
- Weigh the watch head. Platinum should feel far heavier than steel or plated brass.
- Sight the case profile along a table edge. The flanks should be flat and thin, not domed or chunky.
- Check the crown. It should sit small and tight against the case band with no gap.
- Study the dial with a loupe. Look for radial sunburst grain, crisp printed text, and clean marker edges.
- Look at the hands. Thin batons with polished, beveled sides and no burrs.
- Pull the crown to the first position and turn it. There should be no date position, because the 5738 has no date.
- Turn the watch over. You want sapphire, correct caseback engraving, and a visible micro-rotor.
- Examine the movement finish. Geneva stripes, polished bevels, and the Patek Philippe Seal should all be present.
- Check hallmarks on the caseback and the buckle. Platinum hallmarks and a Calatrava cross on the buckle are standard.
- Compare your own photos side by side with catalog photos of the 5738 before you decide.
Where good replicas still fall short
Higher-tier replicas of the Ellipse shape exist, and the better ones get the silhouette and the dial color close. Three points still break them. Thickness is the hardest to hide because the case has to hold a movement, and a working micro-rotor at 2.53 mm is expensive to copy, so most fakes use a thin quartz caliber or a standard automatic hidden behind a solid back. Finish is the second point: the sunburst on a fake is stamped or sprayed, so it flattens near the edges. The third is the caseback, which usually shows generic striping instead of hand-applied Geneva stripes.
Red flags in a listing
- A price that ignores the platinum case and the anniversary status of the reference.
- Seller photos that never show the caseback or the movement.
- No thickness measurement given anywhere in the description.
- Box and papers photographed from across the room but never shown up close.
- A date window on a reference that has none.
Buy the measurement, not the story. If the seller will not hand you caliper numbers, thickness, weight, and a clear caseback shot, treat the watch as a fake and walk away.