A fake IW371743 is a counterfeit copy of the IWC Portugieser chronograph that carries a 3717-series reference, and it is identified by comparing the dial printing, subdial spacing, date aperture, case finishing and caseback engraving against a verified original. Counterfeiters copy the reference number quickly but rarely match the font weight, engraving depth and hand geometry of the real watch. If two or more of those elements are wrong, the watch is not genuine.
What does the IW371743 reference tell you?
The IW371743 is an IWC Portugieser chronograph, a two-register design with a 30-minute counter at 12, small seconds at 6 and a date window at 3. IWC reference numbers encode the case family, material and dial variant, so the same 3717 case appears with several finishes and strap options. Knowing the exact variant matters, because a counterfeit often mixes parts from two different versions.
Dial printing and typography
Genuine IWC dials use thin applied indices and printed lettering with even spacing between characters. On fakes the logo looks heavier, the SCHAFFHAUSEN line drifts off center and the subdial rings sit unevenly. Under a loupe, authentic feuille hands taper to a sharp point rather than a blunt tip.
Case, lugs and crown
Authentic 3717 cases show crisp transitions between brushed and polished surfaces, with no rounding where the lugs meet the case band. Counterfeit cases usually show soft polishing, uneven lug thickness and a crown that feels loose when wound. Chronograph pushers should travel with a short, firm click and reset cleanly.
Caseback and engraving
The caseback carries the reference number, the serial number and IWC's Probus hallmark, and the engraving should be deep and evenly cut. Fakes often use shallow laser etching that looks dotted under magnification, and serial sequences that repeat across multiple listings. A misplaced SWISS MADE stamp on the dial is another common error.
Movement
Match the caseback type to the reference first, since some versions use sapphire display backs and others close with solid steel. Where the movement is visible, genuine IWC finishing includes Geneva stripes on the rotor, perlage on the plates and blued screws. Most counterfeits hide a Valjoux 7750 clone or a Seagull ST19 under a printed rotor.
How do counterfeit grades differ?
- Budget copies: wrong case size, mineral glass, flat printed markers and a rough bracelet.
- Mid-tier replicas: close dimensions and sapphire crystal, but wrong date font and weak engraving.
- High-grade 1:1 replicas: accurate case profile and AR-coated crystal, yet still detectable by movement construction and serial data.
What should you check before paying?
- Ask for macro photos of the dial, caseback engraving and crown in daylight.
- Request a short video showing the chronograph start, stop and reset to zero.
- Confirm that the reference number matches the dial color and case material the seller describes.
- Check the return policy and payment method before sending money.
Is a fake IW371743 waterproof?
No. Counterfeit chronographs normally use untested gaskets, so they leak in pools and showers. Treat even a high-grade replica as splash-resistant unless a watchmaker pressure-tests it.
How much does a fake IW371743 cost?
Prices run from about $60 for budget copies to $400 or more for high-grade replicas with a decorated clone movement. Above that range you are paying for packaging and after-sales support rather than a better watch.
Bottom line
Judge an IW371743 in this order: dial printing, case finishing, engraving, then movement. If a seller cannot provide macro photos and a running chronograph video, treat the watch as unverifiable.