Quick answer
There is no Patek Philippe Nautilus reference 6790. Patek's Nautilus line runs through references such as 3700, 3800, 5711, 5712, 5726, 5800, 5980, 5990, 5811, and the 7010 and 7118 ladies' models. A listing, forum post, or marketplace ad that calls a watch a "Nautilus 6790" is either mislabelling a copy or inventing a reference number to look official. Treat that as the first red flag, then work through the checks below before any money changes hands.
What "6790" usually signals
Fabricated or scrambled reference numbers show up often in counterfeit listings because sellers need a number that sounds plausible but cannot be looked up against a real model. Some sellers pair a made-up number with a real dial style, such as a blue horizontally grooved dial, to borrow credibility from a genuine 5711. Others use numbers from a different Patek family entirely, which a two-minute catalog check exposes.
Prerequisites
- A Patek Philippe reference list or catalog for the model you are looking at
- Calipers and a 10x loupe
- Clear photos of the dial, caseback, movement, clasp, and paperwork from the seller
- A watchmaker or authorized service center willing to inspect the watch in person
Step-by-step verification
- Look up the reference number in Patek's own catalog before you look at the watch. If the number does not exist, stop here.
- Measure the case across the bezel with calipers and compare the result to the published spec for that reference. A 5711/1A measures about 40 mm across; a copy built on a generic case usually misses by a millimetre or more and often sits too thick.
- Study the bezel and case flanks under the loupe. Genuine Nautilus cases have flat satin-brushed surfaces with crisp polished bevels where the planes meet. Copies show soft, rounded edges and brushing that changes direction or stops short.
- Examine the dial grooves, printing, and date window. The horizontal embossed ridges run evenly from edge to edge, the text is sharp under magnification, and the date aperture has a properly finished frame that sits flush with the dial.
- Check the crown and its engraving. It should be signed with the Calatrava cross and screw down smoothly with no grit or wobble.
- Turn the watch over and inspect the movement through the display back. Look for hand-bevelled bridges, Geneva stripes with clean inner angles, and a solid gold rotor. Copy movements are usually modified base calibers with printed or shallow engraving, plated rotors, and visible machining marks.
- Read the case number and movement number off the caseback and compare them with the movement itself and with the certificate. The digits must correspond, and the engraving should be cut into the metal, not printed on top of it.
- Weigh the bracelet and check each link and the clasp. Solid gold references carry visible hallmarks, the links articulate without play, and the clasp stamping is deep and centered.
- Request an Extract from the Archives from Patek Philippe for the case number, or have an authorized service center open the watch and confirm the movement number against their records.
- Complete the sale in person at a watchmaker's bench, or use an escrow service that holds funds until an inspection is finished.
Red flags on listings and paperwork
- A reference number that does not exist in Patek's catalog, including 6790
- A price far below the current market for that reference
- Seller refuses movement photos, refuses an in-person inspection, or pressures you to pay fast
- Blurry photos of the dial, caseback, or serial engraving
- Certificate or box with mismatched numbers, wrong fonts, or photocopied print quality
- Photos that appear on other listings when you run a reverse image search
Where to get a definitive answer
Only Patek Philippe and its authorized service network can confirm a watch against factory records. Independent watchmakers and certified appraisers can confirm whether a movement, case, and dial belong together, and they can spot a re-cased or re-dialed watch. In the United States, buying or selling counterfeit goods is illegal, and Customs and Border Protection can seize counterfeit watches at import. If a seller cannot survive these steps, walk away.