Short Answer

A watch sold as an IW938402 is genuine only when three things agree: the reference number as IWC Schaffhausen publishes it, the caliber inside the case, and the serial number on the paperwork. Replicas of modern IWC models copy the outside closely and fail on the inside. Confirm the reference, the movement, and the registration record before money changes hands. Everything else is a detail check that either supports or breaks the case.

Before You Start

  • A 10x jeweler's loupe and a bright, angled light
  • Clear photos of the movement, caseback, and papers from the seller
  • Access to the IWC reference list and the My IWC registration portal
  • A watchmaker or IWC service center if you can reach one

1. Verify the Reference Number

  1. Look up IW938402 in the official IWC reference list and confirm the model name, case size, and material match the watch in front of you.
  2. Read the reference engraved on the caseback with the loupe and compare it digit by digit to the number on the warranty card.
  3. Reject the watch if the model name on the dial does not exist under that reference, or if the number returns nothing in IWC's own catalog.

2. Check the Movement

  1. Ask the seller for a sharp photo of the movement through the display back, or have a watchmaker open the case.
  2. Read the caliber number on the bridge or rotor and compare it with the caliber IWC lists for that reference.
  3. Inspect the rotor engraving under the loupe. Genuine engraving has crisp, uniform depth; replica engraving looks shallow, shiny, or misaligned.
  4. Check the finishing under angled light: smooth bevels, clean circular graining, and screws that sit flush.
  5. Run the watch on a timing machine and compare the beat rate and amplitude against the specification for that caliber.

3. Inspect Case, Dial, and Crystal

  1. Check dial printing at 10x. Genuine text has sharp edges and even spacing between letters.
  2. Check the alignment of applied indices and the date window. Replicas commonly show a tilted marker or an off-center date.
  3. Look at the crystal from an angle. Genuine sapphire carries anti-reflective coating on both faces, so reflections are faint and slightly blue or purple.
  4. Compare brushing and polishing on the lugs. The transition line should be straight and the brushing direction consistent.
  5. Examine the crown. The logo engraving on a genuine crown is deep and centered; a stamped or etched logo is a warning sign.
  6. Weigh the watch. A case that feels light for its stated material usually means a plated base metal.

4. Match Serial Numbers and Register the Watch

  1. Compare the serial on the caseback with the serial on the warranty card and any service papers.
  2. Enter the watch in the My IWC registration system. A serial that will not register, or registers to a different model, is a strong indicator of a replica.
  3. Call an IWC boutique or authorized service center and ask them to confirm the reference and serial pairing.
  4. Check the box, booklet, and card print quality. Fuzzy text, wrong fonts, and plastic-feeling leather are common on replica packaging.

5. Read the Price and the Seller

  1. Compare the asking price with current market listings for that reference. A genuine watch at a fraction of market value is either fake, stolen, or damaged.
  2. Ask for service history and the name of the watchmaker who last worked on it.
  3. Use escrow or a payment method with buyer protection, and avoid wire transfers to private sellers.
  4. Walk away if the seller refuses movement photos, rushes the sale, or cannot explain where the watch came from.

6. If You Already Bought a Fake

  1. Photograph the watch, the paperwork, and the listing before you contact the seller.
  2. Request a refund in writing and keep every message.
  3. Dispute the payment with your card issuer or platform if the seller refuses.
  4. Have a watchmaker document the findings in writing, since a professional opinion carries weight in a dispute.

Quick Reference

A genuine IW938402 will pass the reference lookup, carry the correct caliber, show crisp engraving, and register under its own serial. A replica usually fails at least one of those four points, and often two. Start with the reference number, move to the movement, and treat the seller's willingness to be checked as part of the test.