The short answer
Most fake Nautilus 5711/1A watches fail on three points: the case profile, the dial printing, and the movement seen through the display back. A genuine 5711/1A measures 40 mm across and about 8.3 mm thick, with a bezel that is brushed on its top face and polished along the beveled edge. Counterfeits run thick, reverse or blur that bezel finish, and print the dial text with the wrong typeface, spacing or weight. Check those three areas first. If a watch passes them, move on to the bracelet, the clasp, the serial numbers and the paperwork.
What you need before you start
- A 10x loupe
- Digital calipers
- A gram scale
- Reference photos of the exact reference you are viewing: 5711/1A-010 blue dial, 5711/1A-011 white dial, 5711/1A-014 green dial
- A UV flashlight
- Permission from the seller to open the caseback or to have a watchmaker open it
Step-by-step authentication
- Measure the case. Set the calipers across the bezel at the 3 and 9 o'clock points, then measure thickness from the caseback to the top of the crystal. A true 5711/1A reads 40 mm wide and close to 8.3 mm thick. Fakes run from 1 to 2 mm thick.
- Examine the bezel. The top face carries a fine satin brush and the angled side is polished to a mirror. Under the loupe the line between the two finishes is sharp. Fake bezels come fully polished, fully brushed, or with a soft, rounded transition.
- Read the dial text. At 12 o'clock, "Patek Philippe" sits above "Genève" with the accent on the first e. At 6 o'clock you see "Automatic". Letters must be crisp and evenly spaced with no ink bleed. Many fakes show thick letters, tight or uneven spacing, and a missing accent.
- Tilt the dial under a light. The blue dial is sunburst brushed and shifts tone as the angle changes, from deep blue at the edges to a brighter blue in the center. Fake dials stay flat, or turn purple or neon in direct light.
- Inspect the hands and markers. Hour and minute hands are faceted white gold with clean edges and an even lume fill. Applied markers are white gold with polished sides. Look at the date window at 3 o'clock. The date font must match Patek's own, sit centered in the aperture, and align with the printed frame.
- Weigh the watch. Place the full watch on the scale and compare with a known figure for the reference. Hollow links, a thinner caseback, and lower grade steel push fakes outside the expected band.
- Check the bracelet and clasp. Links carry a satin brush on the top surface with polished bevels, and the fit between links is tight with no rattle. The folding clasp should close with one firm click and carry a deep, sharp Calatrava cross. Fake clasps feel thin and the engraving looks shallow or sandblasted.
- Test the crown. It is engraved with the Calatrava cross and screws down in a few smooth turns with no grit. A stiff or wobbly crown points to a copy case.
- Look through the display back. Earlier 5711/1A watches used the calibre 324 S C and later examples used the 26-330 S C. Bridges show Geneva stripes and beveled edges, and the gold rotor carries the Calatrava cross plus the Patek Philippe name. The calibre number and movement number are engraved on the bridge. Fakes show the wrong calibre number, flat decoration, and a balance wheel of the wrong shape.
- Match every number. The case number, the movement number on the bridge, and the numbers on the papers must agree. Patek Philippe can confirm a watch through its archives service.
- Check the price and the provenance. A steel 5711/1A trades above its old retail price on the secondary market. A price far under market, a seller who blocks a caseback inspection, or a watch with no box and no papers are all reasons to walk away.
Red flags that end the inspection
Dial and case
- Bezel all polished or all brushed
- Dial text with a missing accent or heavy, uneven letters
- Case wider than 40 mm or thicker than about 8.5 mm
- Date font that does not match the reference
Movement and numbers
- Calibre number on the bridge that does not match the reference year
- Rotor engraving that looks laser printed rather than cut
- Case, movement and paper numbers that do not agree
If you are buying online
Ask for a video call with the watch in hand, then request photos taken through a loupe of the dial text, the bezel edge, the clasp and the movement. Pay through a method that allows a dispute, and arrange a third party inspection with a watchmaker or an authorized service center before the return window closes. A seller who refuses any of these steps is telling you what the watch is.