A fake IW371620 is a counterfeit of the IWC Portugieser Chronograph, and it almost always fails in the same place: the movement. The real watch runs IWC's in-house calibre 69355, a column-wheel chronograph with a vertical clutch and a 46-hour power reserve, so replicas built on a Valjoux 7750 or Seagull ST19 base cannot match the subdial layout, the pusher feel or the case thickness.
Why is the IW371620 hard to copy?
The IW371620 uses a bicompax dial with running seconds at 6 o'clock and a 30-minute counter at 12 o'clock, with no date window anywhere. A 7750-based counterfeit is a tri-compax movement with a day and date, so builders have to blank out one subdial and hide the calendar aperture. That compromise shows up as a dead subdial, a mismatched hand length or a thicker case than the original.
How do you check the movement?
- Pusher feel: the genuine 69355 starts and stops with a light, mechanical click from the column wheel, not the spongy travel of a cam-actuated clone.
- Rotor finishing: look for Geneva stripes, blued screws and the IWC Probus Scafusia medallion on the oscillating weight.
- Beat rate: the calibre runs at 28,800 vibrations per hour, so the seconds hand sweeps smoothly rather than ticking.
- Caseback: the reference is engraved with the model number and serial, and both should match the paperwork.
What dial and case details give a fake away?
Genuine dial printing is razor sharp, with thin strokes on the IWC Schaffhausen signature and evenly spaced minute track. Counterfeits tend to show heavier type, fuzzy edges under magnification and subdial rings that are stamped instead of snailed. The feuille hands should reach the minute track exactly, with mirror-polished bevels that catch light along their full length.
Case finishing is the second giveaway. The original measures roughly 12.3 mm thick with crisp transitions between brushed flanks and a polished bezel, while most replicas run 0.5 to 1.5 mm thicker and show soft, rounded lug edges. Check the crystal too, since sapphire with double anti-reflective coating carries a faint blue tint at steep angles.
Red flags in a listing
- A price far below the current market range for a steel Portugieser Chronograph.
- Reused stock photos, no macro shots of the movement or caseback engraving.
- A seller who cannot show a serial checked against IWC service records.
- Missing box, warranty card or service history on a supposedly recent reference.
Is a super clone IW371620 identical to the real thing?
No. Even the best replicas approximate the exterior and rely on a modified 7750 or ST19 movement, so the chronograph action, decoration and long-term serviceability stay distinct. Anyone comparing the two side by side will notice the pusher feel within seconds.
Quick verification checklist
- Confirm the bicompax layout with no date.
- Inspect the rotor and balance through the display back.
- Measure case thickness and weight.
- Magnify the dial printing and subdial rings.
- Match reference and serial engraving to the documents.