Short answer
A fake IW371653 is a counterfeit copy of an IWC Portugieser Chronograph. IWC does not build it. No authorized dealer sells it. The reference number appears on casebacks, marketplace listings, and forum posts, and a copy can carry that number with a serial that IWC service cannot confirm. This guide could not verify a public IWC page that lists IW371653 as a standalone reference.
Reference facts
- Model line: IWC Portugieser Chronograph, current generation.
- Case: 41 mm, stainless steel, sapphire crystal front and back.
- Movement: caliber 69355, automatic, 4 Hz, 46-hour power reserve.
- Dial: subdials at 12 and 6. Two hands, two counters.
- Strap: alligator leather on a pin buckle or folding clasp.
IWC service can confirm a case number, a dial code, and a delivery date. Do that before you pay. IWC does not keep a public archive page for every reference number, so written confirmation from the brand is the check that holds.
Where copies fail inspection
- Subdial spacing. A donor movement has a different layout, so the counters sit at the wrong height.
- Movement finish. Genuine bridges show Geneva stripes over a perlage base. Copies use sprayed decoration that flakes.
- Rotor text. IWC engraves the caliber and the brand on the rotor. Copies stamp it, and the letters bleed at the edges.
- Caseback and serial. Genuine engraving is deep. Copy engraving is shallow, and the serial format does not match IWC records.
- Pushers and crown. Genuine pushers have short travel and a firm stop. Copy pushers wobble.
- Papers. A genuine set has a guarantee card with the reference, the serial, and a dealer stamp. Copy sets use printed cards with spelling errors.
Price gap
A new Portugieser Chronograph sells for about $7,000 to $8,000 in the United States. Used examples trade lower, near $5,000 to $7,000. A counterfeit sells for $50 to $600. A seller who offers a boxed IWC at 5 percent of retail is selling a fake.
Law in the United States
Trafficking in counterfeit goods is a federal crime under 18 U.S.C. 2320. A first offense carries up to 10 years in prison and a fine. Repeat offenses carry up to 20 years. CBP can seize counterfeit watches at the border, and the trademark owner can sue the seller under the Lanham Act. Personal use carries lower risk than resale, but import of a counterfeit watch is barred.
If you own one
Ask IWC service to inspect the watch. A rejection of the serial number ends the question. Do not resell it as genuine. A sale with a false claim of authenticity exposes the seller to a Lanham Act claim and to criminal charges.