A fake IW371747 is a counterfeit copy of an IWC Portugieser Chronograph, built to look like the genuine reference without matching its materials, finishing, or movement. The fastest tells are the subdial spacing at 12 and 6, the case thickness on the wrist, and the movement visible through the sapphire caseback. If the subdials sit too far apart, or the case feels bulky for a slim dress chronograph, the watch is very likely a replica rather than the real thing.

What the IW371747 Actually Is

The IW371747 sits inside IWC's Portugieser Chronograph family, a line defined by a clean two-register dial, applied markers, leaf-shaped hands, and a slim stainless steel case. The numeric suffix identifies a specific dial and strap combination inside that family, so two watches sharing a base reference can look quite different. Before judging any watch, confirm the exact specification against IWC's own reference data, since dealers and resellers sometimes list watches under the wrong number.

Why This Reference Gets Copied

Portugieser Chronographs are popular, heavily photographed, and expensive enough that a convincing copy is profitable. That combination is exactly what counterfeiters look for. The good news is that this reference is also straightforward to check in person, because so much of its design depends on precise spacing and thin proportions that budget copies struggle to reproduce.

How to Spot a Fake IW371747

Dial and Subdial Layout

  • Subdial spacing. Genuine two-register dials keep running seconds and chronograph minutes close to the center. On many fakes, the subdials drift outward or sit on a different horizontal line.
  • Print quality. Study the brand lettering and the Schaffhausen text under magnification. Genuine printing is sharp and evenly spaced. Copies often show fuzzy edges, uneven letter heights, or ink that sits raised.
  • Applied markers. Genuine applied markers are polished on top with crisp, straight sides. Replica markers frequently look flat, rounded, or slightly misaligned.
  • Hands. Leaf hands should be cleanly finished with a sharp central ridge and no burrs. Blued hands should show a deep, consistent tone rather than painted blue.

Case, Crystal, and Feel

  • Thickness and weight. A genuine thin chronograph case sits low on the wrist. Many fakes add a millimeter or two, mostly to fit a thicker movement.
  • Crystal coating. Genuine sapphire carries an anti-reflective treatment that keeps reflections muted. Cheap crystals look shinier and show a strong blue or purple tint at an angle.
  • Crown and pushers. Screw-down crowns should thread smoothly and stop cleanly. Pushers should have short, defined travel with no gritty feel.

Movement

This is where most fakes fall apart. Open the caseback, or ask for clear macro photos of it. Genuine IWC chronograph movements show clean striping, polished bevels, blued screws, and engraving that matches the reference exactly. Copies usually hide a stock chronograph movement behind a decorative rotor plate, with shallow engraving and obvious machining marks. If the seller refuses to show the movement, treat that as an answer.

Caseback, Serial, and Paperwork

  • Engraved reference and serial numbers should be deep, straight, and consistent in font.
  • The reference number on the caseback must match the papers and the number you verified with IWC.
  • Check the strap hardware. Genuine buckles and deployants are heavier, with crisp engraving and clean spring bars.
  • Copies often ship with generic boxes and cards printed slightly off-center. Packaging alone never proves authenticity, but it is a useful tiebreaker.

Questions to Ask Before You Buy

  1. Can you send sharp macro photos of the dial, caseback, and movement?
  2. Does the reference number on the caseback match the paperwork?
  3. Has the watch been serviced, and by whom?
  4. What is your return window if authentication fails?

Get It Authenticated

No guide replaces hands-on inspection by a watchmaker who services IWC. A qualified watchmaker can time the movement, check finishing under a loupe, and confirm the caliber against the reference. If a price sits far below the market for the reference, that gap is itself evidence. Budget for authentication on any private sale, and walk away if the seller resists it.