Short answer
A watch offered as an IWC IW371410 is fake when it fails three checks: case size, dial layout, and movement. The IW371410 sits in the Portugieser Chronograph 3714 family. IWC built that line around a 40.9 mm steel case, a 12.3 mm height, and calibre 79350. A fake misses at least one of those numbers. The movement is the hardest part to copy.
Case size and finish
- Genuine: 40.9 mm diameter, 12.3 mm thick, polished steel bezel, 20 mm lug width.
- Fake: 40 mm or 42 mm cases. Height of 13.5 mm to 15 mm. The extra thickness comes from a stock movement plus a spacer ring.
- Genuine steel has weight in the hand. Plated brass and zinc alloy cases feel light and warm.
- Lug shape on fakes is squarer, and the caseback lip sits proud of the case.
Dial and hands
- Layout: small seconds at 6 o'clock, 30-minute counter at 12, date aperture at 3.
- Numerals: applied Arabic numerals with a polished top and a step at the base. Gold or rhodium finish.
- Hands: leaf shape, thin, with a clean polish line down the center.
- Fakes: printed flat numerals, fat hands, subdials set too high or too low, date window off center, wrong logo font.
Movement
Calibre 79350 is a Valjoux 7750 base, reworked and finished by IWC. It beats at 28,800 vph (4 Hz). Power reserve is 44 hours. Most 3714 references use a sapphire display back, so the movement is visible.
Fake IW371410 Alternative Brands Comparison Review
- Rotor: IWC medallion and "Probus Scafusia" in sharp relief. Fakes show shallow laser etching.
- Rate: 28,800 vph. A 21,600 vph beat is a fake tell. Count beats with a timegrapher.
- Finishing: Geneva stripes, blued screws, perlage on the plates. Clones arrive plain.
- Pushers: firm start, stop, and reset. Clones feel spongy or gritty.
Caseback, reference, serial
Engraving is deep and sharp: reference number, serial number, "International Watch Co.", "Schaffhausen", "Sapphire Crystal", "Stainless Steel". The reference reads IW371410 or another IW3714xx number. The serial runs 7 or 8 digits. Compare the serial on the caseback, the papers, and the IWC service record. A mismatch points to a fake case, a swapped back, or a frankenwatch.
Strap, buckle, paperwork
- Strap: signed IWC alligator with a set taper and stitch count. Fakes ship generic leather with a different grain.
- Buckle: steel pin or deployant, stamped "IWC", hard edges, crisp logotype.
- Papers: booklet, warranty card, hang tag. Serials and reference must agree across all three.
Why a replica still fails
A high grade replica can match the 40.9 mm case and the dial layout. It fails at the movement. A finished 79350 costs more than the whole fake watch. Open the case and you find a 7750 clone with a printed rotor. Under a loupe, the engraving depth, the hand polish, and the dial print give the rest away.
How to check before you pay
- Measure the case with calipers. 40.9 mm and 12.3 mm are the numbers to match.
- Photograph the movement and read the rotor text.
- Ask for the serial and the reference on the papers.
- Take the watch to an IWC service center for a written check.
- Compare price. A steel 3714 in working order trades in the low thousands of dollars. A price far below that is a warning.