What a fake IW371747 actually is
A fake IW371747 is a watch sold under the reference number of the IWC Portugieser Chronograph 3717 family but built by a third party. The reference itself is real. Copies exist because the model is popular, well photographed, and widely documented, which gives a counterfeiter plenty of material to work from. If a seller hands you a watch and calls it an IW371747, the only question that matters is whether the case, dial, movement, and papers match what IWC built for that exact reference.
Before you inspect
- A loupe or a phone macro lens
- Bright, angled light
- Official reference data for the exact variant
- Sharp photos of the case back and the movement
Step-by-step checks
- Confirm the reference on the case back. Genuine examples engrave the reference, serial, and case material in a consistent font and depth. Copies use shallow laser etching or a font weight that does not match.
- Measure the case. Compare diameter, thickness, and lug width against the official spec for that variant. Half a millimeter is normal variation. Two millimeters is a copy.
- Read the dial under magnification. Check the brand mark, the line of text under it, and the minute track. Genuine printing stays crisp at 10x. Copies show fuzzy edges, uneven spacing, or a font that runs thick.
- Inspect the subdials. Subdial spacing, hand lengths, and the position of the date window are the hardest details for a copy to get right. Compare against a verified photo of the same reference, not a different Portugieser.
- Check the hands and applied markers. Genuine hands carry polished bevels and sharp tips. Copies show raw edges, a dull finish, or lume that sits proud of the metal.
- Fire the chronograph. Start, stop, and reset it. The pushers should feel firm and click cleanly. A mushy pusher or a reset that drags points to a cheap modular movement.
- Look at the movement. Genuine watches in this family use an IWC chronograph caliber with a signed rotor and specific finishing visible through the case back. Generic stamping, blank bridges, or a plastic movement ring are red flags.
- Weigh the watch in hand. Steel and precious metal have a density you can feel. Copies tend to feel light or hollow.
- Check the strap and hardware. Genuine straps show even stitching and a signed buckle or deployant with crisp engraving.
- Verify the paperwork. Serial number, reference, and case material must match across the warranty card, the case back, and the movement. A seller who will not photograph all three is telling you something.
Where copies give themselves away
Most fakes fail in the same three places: dial printing, subdial spacing, and movement finishing. Case polishing is often close enough to survive a photo. A loupe and a chronograph test catch the rest.
If you are buying online
Ask for a video of the chronograph running and a macro shot of the case back. Compare the reference digits character by character against official data. Treat stock images, no-returns policies, and prices far below market for the stated condition as warnings. When the price is the only thing that looks right, the watch is not.