A fake IW371432 usually gives itself away in three places: the printing on the dial, the shape of the case and lugs, and the movement behind the caseback. The genuine IWC Portugieser Chronograph in this reference family measures 40.9 mm across, uses applied Arabic numerals with feuille hands, and runs a Valjoux-based chronograph calibre. A replica can copy the silhouette from across a table, but it rarely gets all of those details right at the same time.

This guide runs through the checks a watchmaker or an experienced collector uses, ordered from the fastest to the most conclusive.

What the IW371432 actually is

This reference sits in the IWC Portugieser Chronograph line, a two-register design with a 30-minute counter at 12 o'clock and running seconds at 6 o'clock. The case is stainless steel with long straight lugs and a narrow bezel, and the dial sits under a box-domed sapphire crystal. Production years and calibre details vary across the family, so confirm the exact reference against IWC's own documentation before you buy or compare.

Dial and hands: the fastest checks

  • Printing. The "International Watch Co." script and "SCHAFFHAUSEN" text should be sharp, evenly spaced, and level. Soft or bleeding edges are common on replicas.
  • Numerals. Applied, polished, and set at even heights around the dial. Fakes often sit slightly crooked or use flat printed numbers.
  • Subdials. Correct spacing between the two registers and hands that line up cleanly on their center pins.
  • Hands. Feuille shape with a clean taper and a mirror polish. Replica hands tend to look thicker, duller, or slightly wrong in the curve.
  • Minute track. Crisp divisions with no ink bleed and no gaps in the ring.

Case, crystal, and caseback

  • Case profile. Check the diameter, thickness, and lug-to-lug figure against the published specs. Replicas often run slightly thick or have lugs that curve a touch too much.
  • Crown and pushers. The crown should have clean knurling and the pushers should give a firm, defined click with no mush.
  • Crystal. Box-domed sapphire with an anti-reflective treatment that keeps the dial readable at an angle.
  • Engraving. Reference and serial numbers are cut clean, in the right font, at a consistent depth. Steel versions of this family typically use a solid caseback. Shallow laser etching is a warning sign.

Movement: where replicas run out of road

Older Portugieser Chronograph references in the 3714 family are documented as using IWC calibre 79350, a Valjoux 7750 base that IWC reworked and finished in house. That architecture sets the pusher feel, the winding smoothness, and the way the chronograph seconds snap to zero. A quartz movement or a basic chronograph module is an instant giveaway, and it becomes obvious the moment a watchmaker opens the back. On a genuine piece you expect decorated bridges, a signed rotor, and a balance running at 28,800 vibrations per hour.

Strap, bracelet, and hardware

The strap should be a signed leather band with even stitching, or a bracelet with tight end links and a clasp that closes with a solid click. Replica hardware often shows rough edges on the clasp, uneven spring bars, and stitching that wanders. Thread and leather quality degrade quickly on cheaper builds, so a worn strap on a supposedly new watch deserves a closer look.

How close do super clones get?

High-end replica builds of this reference can match the case dimensions, dial layout, and crystal shape closely enough to pass a casual glance. Some use a Valjoux 7750-based movement, which copies the pusher feel and the subdial behavior. What still separates them from the genuine article is execution: the depth and finish of the caseback engraving, the sharpness of the dial print, the polish on the hands, and the consistency of the case finishing from one example to the next.

How to confirm authenticity before you buy

  1. Buy the seller. Ask for the original paperwork, service records, and a clear photo of the caseback engraving.
  2. Request a movement photo or a service receipt that names the calibre.
  3. Have a watchmaker or an authorized service center open the case.
  4. Check the price against current market listings. A genuine Portugieser Chronograph does not sell for a few hundred dollars.

Bottom line

A fake IW371432 fails on the small things: dial printing, subdial spacing, case thickness, engraving depth, and the movement inside. Work through the checks in order, and if anything feels off, walk away or insist on an inspection by a qualified watchmaker before money changes hands.