If a watch is offered as an IWC IW93856, treat the reference as unverified until you can prove otherwise. IWC publishes its reference numbers in two patterns: IW plus four digits with a dash and a two-digit material code, or IW plus six digits. A five-digit string such as IW93856 fits neither pattern, so the number itself is the first thing to test before you study the watch.

Prerequisites

  • A 10x jeweler's loupe
  • Digital calipers that read to 0.1 mm
  • Bright raking light and a clean cloth background
  • Access to IWC's published model list or an authorized dealer
  • A watchmaker willing to open the caseback

Step-by-step inspection

  1. Write down the full reference string on the caseback and compare it with IWC's published numbering pattern.
  2. Photograph the caseback at 10x and study engraving depth, letter spacing, and font weight.
  3. Read the serial number and confirm it is one continuous string with no repeated blocks or mixed fonts.
  4. Measure case diameter, thickness, and lug width, then compare each figure with the published specification.
  5. Inspect the dial under the loupe for applied indices, clean lume fill, and correct logo lettering.
  6. Wind the crown and set the date; note whether the crown threads smoothly and the date snaps at midnight.
  7. Have a watchmaker remove the caseback and examine movement finish, rotor engraving, and jewel count.
  8. Check the hands for sharp edges and a finish consistent with the model.
  9. Compare the warranty card, booklet, and box numbers against the case serial number.
  10. Ask an IWC service center or an independent watchmaker to confirm the reference in writing.

Red flags that stop the sale

  • The reference has five digits or a letter mix IWC does not use.
  • Caseback engraving is shallow, laser-etched, or spaced unevenly.
  • The case serial number does not match the papers.
  • Case dimensions are off by more than 0.2 mm from published figures.
  • The movement shows no jewel count, no engraving, or visible plastic parts.
  • The seller refuses a third-party inspection.

If the watch turns out to be fake

Stop the transaction and keep every message, photo, and receipt. Report the listing to the platform, then file a report with your national customs or consumer protection agency. In the United States, counterfeit goods fall under trademark law and goods can be seized at the border. A written statement from a watchmaker strengthens a chargeback or a refund claim.