Answer first

A watch sold as IW938989 is genuine only when that exact reference resolves to a documented IWC model with matching case size, movement, and dial variant. IWC reference numbers use the IW prefix followed by six digits, and each one maps to one precise configuration. If a seller cannot show a catalog match, or if the physical watch does not match the catalog specs, treat it as counterfeit or misdescribed. Run the checks below in order and stop as soon as two of them fail.

Prerequisites

  • 10x jeweler's loupe or a macro lens
  • Digital calipers and a gram scale
  • The reference and serial numbers, read from the case back
  • Reference photos of the same model from an authorized dealer or the IWC site
  • A steady table and bright, angled light

Steps

  1. Write down the full reference string from the case back and confirm it follows the IW plus six digit pattern.
  2. Search that exact reference in IWC's official product database and screenshot the model page for comparison.
  3. Compare the catalog case diameter, thickness, and water resistance rating against your measured numbers with calipers.
  4. Weigh the watch head on a gram scale and compare it to the published weight for the same reference and material.
  5. Examine the case back engraving with the loupe and check that letters are crisp, evenly spaced, and cut into the metal rather than printed on top.
  6. Inspect the dial printing under magnification and confirm that text edges are sharp with no ink bleed or uneven spacing between letters.
  7. Check that applied hour markers sit flat, reflect light at the same angle, and are not glued on crooked.
  8. Turn the crown through its full range and note whether the threads engage smoothly with no grit or wobble.
  9. Start the chronograph, let it run for two minutes, then reset it and confirm the hands snap back to zero in one motion.
  10. Look through the display back at the movement and check the rotor engraving, bridge finishing, and jewel count against the catalog specification.
  11. Compare the serial number on the case back with the serial on the movement, since mismatched numbers point to a swapped or rebuilt watch.
  12. Inspect the bracelet end links or strap stitching for uniform gaps, correct taper, and hardware that matches the catalog finish.
  13. Ask the seller for the original warranty card and box, then verify the card serial against the watch.
  14. Take the watch to an authorized IWC service center and request a written authenticity assessment before you pay.

Reading the results

Any single mismatch can have an innocent explanation, such as a factory service replacement or a misread digit. Two or more mismatches on dimensions, engraving depth, and movement finishing together point to a counterfeit. Counterfeiters copy the visible details well but rarely match case tolerances, movement decoration, or serial continuity between case and movement.

When to walk away

Walk away if the seller refuses an inspection by an authorized service center, if the price sits far below the market for that reference, or if the reference number cannot be found in IWC's own product list. A reference that does not exist in the catalog cannot be authenticated at all, no matter how good the watch looks in photos.