If you are trying to work out whether an IW371775 is genuine, the fastest answer comes from the reference number itself: IW371775 does not appear in IWC's published catalog, so any watch sold under that exact reference deserves scrutiny before money changes hands. The criteria below are ordered by how fast they settle the question: reference validity, movement and caseback engraving, dial and hand finishing, and provenance. Buyers who only want the Pilot's Chronograph look should read the three options at the end, which cover the genuine, replica and walk-away paths with their trade-offs stated plainly.

What IW371775 Is Supposed to Be

IWC reference numbers follow family blocks. The IW3717xx block covers the stainless steel Pilot's Watch Chronograph built in the 2000s and early 2010s: a 42 mm automatic chronograph with a day and date window at 3 o'clock and a three-register dial. Factory references inside that block are documented, and IW371775 is not among the widely documented members. That does not automatically make every watch sold under it counterfeit, because regional releases, boutique editions and plain seller typos all exist. It does mean the burden of proof sits with the seller, not with you.

Criterion 1: The Reference Number Test

  • Pro: takes thirty seconds, needs no tools and no watchmaker.
  • Pro: a mismatch between the caseback reference, the papers and the warranty card is a hard stop.
  • Con: a correct number proves almost nothing, because counterfeiters engrave the same numbers as the factory.
  • Con: a handful of genuine limited editions are absent from public catalogs, so the test produces false alarms.

Treat this as a filter rather than a verdict. Ask the seller for a straight-on photo of the caseback and a photo of the paperwork side by side. If the numbers do not match, stop there. If they match, move to the movement.

Criterion 2: Movement, Caseback and Rotor

The IW3717 family runs the IWC caliber 79320, a chronograph movement built on the Valjoux 7750 architecture, running at 28,800 vibrations per hour with a power reserve in the region of 44 hours. That architecture is common, which is exactly why so many look-alikes exist. What separates them is finishing: the rotor engraving, the perlage and Geneva stripes, the quality of the screws and the crispness of the movement stamping.

  • Pro: movement finish is expensive to copy well, so it exposes budget fakes faster than any exterior detail.
  • Pro: a watchmaker can confirm the caliber during a routine service estimate.
  • Con: you cannot verify the movement without opening the case, which you should not do to a watch you do not yet own.
  • Con: on a watch this old, an original movement may have been swapped during an undocumented repair, muddying the result.

Criterion 3: Dial, Hands and Crystal

Dial printing is where most replicas slip. Check the spacing and weight of the brand text, the alignment of the day and date discs inside the 3 o'clock window, the applied indices and their lume fill, and the subdial hand lengths against photographs of a documented reference. Genuine sapphire crystals carry an anti-reflective coating that shifts color at an angle. Hands should have clean edges with even lume. On replicas, the date font is usually too bold, the lume fill sits unevenly and the crystal reflects flat grey instead of showing a coating tint.

Criterion 4: Provenance

Ask for the original invoice, the warranty booklet with matching serial, and the service history. A seller who has the watch in hand but cannot produce a single document for a watch this valuable is telling you something. Independent authentication from a watchmaker costs far less than the difference between a genuine chronograph and a counterfeit.

Option 1: Buy a Genuine IWC Pilot's Chronograph

  • Pro: real movement, real service support, real resale value.
  • Pro: no nagging doubt every time someone asks about the watch.
  • Con: entry prices for the IW3717 family sit well into four figures.
  • Con: older examples often need a service shortly after purchase.

Best for buyers who treat the watch as an asset and intend to keep or resell it. Confirm the reference against IWC documentation and budget for a service.

Option 2: Buy a High-Grade Replica

  • Pro: you get the 42 mm pilot chronograph silhouette, the day-date layout and the dial proportions at a small fraction of the cost.
  • Pro: no service anxiety on a watch you can replace.
  • Con: no factory service, no warranty from the brand, and no resale value.
  • Con: quality varies sharply between sellers, so the movement and finishing must be checked on arrival.

Best for buyers who want the look for daily wear and accept that it is not an investment. Ask for movement photos and caseback photos before ordering, and confirm the reference logic above so you know what you are actually buying.

Option 3: Walk Away and Get It Authenticated

  • Pro: costs little and removes all doubt.
  • Pro: protects you if the seller is misrepresenting the reference.
  • Con: adds days or weeks to the purchase.
  • Con: some sellers refuse to allow third-party inspection, which itself is informative.

Best for any deal where the price looks too low for a genuine chronograph or the paperwork is thin.

Bottom Line

IW371775 is not a catalog reference you can verify from public IWC material, and that alone should slow the transaction down. Run the four checks in order. If the reference, movement finish, dial print and paperwork all line up, you are likely looking at a genuine watch or a very well-built replica. If any one of them fails, treat the watch as a replica regardless of what the listing says, and decide whether the replica price still makes sense to you.