Answer in short

IW371652 sits in the IWC Portugieser Chronograph family, reference 3716. A fake IW371652 is a copy built in China or Hong Kong and sold under that number. The copies run third-party movements, not the IWC caliber 69355. Case thickness, subdial layout, dial printing, and caseback engraving differ from the genuine watch. Copy prices run from about $250 to $1,200. The genuine watch sells near $8,000 on a strap and near $9,300 on a bracelet at US retail. Prices change with the year.

What IW371652 is

IWC lists the Portugieser Chronograph with a 41.0 mm steel case, sapphire crystal, and the in-house automatic caliber 69355. Power reserve is 46 hours. Frequency is 4 Hz, or 28,800 vibrations per hour. The dial carries a 30-minute counter at 12 o'clock, running seconds at 6 o'clock, and a date window at 3. Water resistance is 3 bar.

Not every number in the 3716 range appears in public IWC material. If a listing shows IW371652 and you cannot match the dial, case, and strap to an IWC catalog entry for that variant, treat the number as unverified. Replica sellers reuse and invent reference numbers. Ask an IWC boutique or service center to confirm the original configuration.

Movement: the largest gap

Ask for a photo of the caseback with the movement visible. Three checks settle most questions.

  • Subdial layout. Caliber 69355 drives 30 minutes at 12 and small seconds at 6. A Valjoux 7750 or a 7750 clone drives 30 minutes at 12, 12 hours at 6, and small seconds at 9. Running seconds at 9 o'clock is the giveaway.
  • Winding. The genuine watch is automatic. Some copies use a hand-wound Seagull ST19. No rotor under a display back means no 69355.
  • Finishing. The IWC movement shows circular graining on the bridges, perlage on the main plate, and blued screws. Copies show stamp marks, rough edges, and paint where bluing should be.

Case, crystal, and dial checks

  • Measure the case. Genuine 3716 measures 41.0 mm across and about 13.1 mm thick. Many copies measure 42 mm and 14 to 15 mm thick.
  • Crystal. Sapphire with anti-reflective coating. Copies show strong purple or blue reflections across the dial.
  • Dial printing. Under a loupe, the letters are sharp and evenly spaced. Copies show thick strokes, loose spacing, and missing serifs.
  • Subdials. Genuine subdials sit in a recess with a circular snailed finish and a thin polished ring. Copies print the rings flat.
  • Date window. The genuine aperture is beveled and the numeral font matches the dial. Copies use generic date wheels with a different numeral shape.
  • Applied numerals. Polished with crisp edges. Copies use stamped metal with rounded edges and weak reflections.

Caseback and engraving

The genuine watch has a sapphire display back. The outer ring carries the reference number, the serial number, the IWC name, Swiss Made, and the water resistance figure. Copies engrave to a shallow depth and use the wrong fonts. Serial numbers on copies repeat across listings. If two listings show the same serial, both are fake.

Box, papers, and price

A genuine IW371652 ships with a box, a manual, and a warranty card. IWC extends the international warranty to 8 years when the owner registers the watch in the My IWC program. A seller who offers a full set for $800 is selling a fake.

Approximate US prices from 2025 listings: genuine 3716 on a leather strap about $8,000 new and $5,500 to $7,000 used. Bracelet version about $9,300 new. Copies $250 to $1,200. A genuine IWC at $600 does not exist, and that price alone ends the question.

Legal position in the United States

Trafficking in counterfeit goods is a federal crime under 18 U.S.C. section 2320, with prison time and fines. US Customs and Border Protection seizes counterfeit watches at import. The buyer loses the watch and gets no refund. Selling a counterfeit watch as genuine also exposes the seller to civil liability under the Lanham Act.

Checklist before you buy or bid

  1. Request a caseback photo with the movement visible.
  2. Count the subdials. Two, at 12 and 6. Three, or seconds at 9, means no.
  3. Request case thickness measured with calipers.
  4. Request macro photos of the reference and serial engraving.
  5. Compare the dial photo to an IWC product image for the exact variant.
  6. Compare the price to used market data for reference 3716.
  7. Request the warranty card and any IWC service record.

Where the record runs out

Public IWC records do not cover every number in the 3716 range, and this guide cannot confirm the exact dial, strap, or production year for IW371652. Only IWC can confirm that. Verify before you pay, and treat any listing that refuses verification as a fake.