A fake IW371478 gives itself away in four places: the reference number does not match IWC's own records, the subdials sit at the wrong spacing, the caseback engraving is shallow and grey, and the movement is a stock 7750 with no IWC finishing. Check the reference in IWC's product archive before anything else. Reference numbers in the 3714 block belong to the Portugieser Chronograph line, so a listing that pairs the number with another model or a different case size is already suspect.
Prerequisites
- A 10x jeweler's loupe or a phone with a macro lens
- Digital calipers for case diameter and thickness
- IWC's official reference archive open on a second screen
- A timing app, or a watchmaker who can read rate and amplitude
How to Spot a Fake IW371478
- Confirm the reference exists. Search 371478 in IWC's product archive and compare the case material, dial color, and strap it lists. No result, or a different dial, means stop.
- Measure the case. A Portugieser Chronograph in the 3714 block runs 40.9 mm across, crown excluded, and about 12.3 mm thick. Counterfeits often sit 1 to 2 mm off because they use a generic case.
- Study the subdials. The 3714 layout puts the chronograph minutes at 12 o'clock and small seconds at 6. Fakes show oversized subdial rings, short hands, and printed tracks that miss the pinion centers.
- Read the dial print under magnification. Genuine IWC and SCHAFFHAUSEN text has sharp serifs and even stroke weight. Counterfeit print bleeds at the edges and drifts along the curve.
- Check hands and markers. Applied numerals carry polished bevels that catch light in a straight line. Fake markers look flat, and the feuille hands show rough edges under raking light.
- Inspect the caseback engraving. Genuine engraving is deep and even, with reference and serial numbers that match IWC's records. Electro-etched fakes look shallow, grey, and soft at the edges.
- Test the crown and pushers. Genuine pushers have a firm, short click and the crown screws down with clean threads. Gritty or rattling pushers point to a cheap chronograph module.
- Have the movement inspected. The 3714 uses IWC calibre 79350, a reworked 7750 base. A watchmaker checks for the IWC rotor engraving, jewel count, and bridge finishing. An unmarked 7750 with a glued-on rotor is counterfeit.
- Time the watch. Ask for a rate reading. A serviced 79350 holds roughly -5 to +15 seconds a day with low beat error. Counterfeit movements show wide amplitude swings.
- Verify price and paperwork. A 3714 offered far under the going resale range, or sold with a warranty card no dealer can match to a serial, is not a bargain.
Common Failure Points
- Certificate that lists a reference the watch does not carry
- Blued screws painted rather than heat treated
- Crystal without the double anti-reflective coating
- Date numerals sitting off center in the window
- Strap stitching and buckle stamping that do not match the catalog photo
What to Do Next
Take the watch to an IWC authorized dealer or a watchmaker who services the brand and ask for the findings in writing. If the piece turns out to be counterfeit, keep the listing, photos, and payment records. Counterfeit watches are illegal to import and sell in the United States, so a refund request through your payment provider or a report to the rights holder is a reasonable next step. Use established marketplace listings as your price benchmark, since a genuine reference trades in a narrow band and a fake almost never does.