A fake IW371620 is a counterfeit copy of an IWC Portugieser Chronograph. The genuine watch has a 41 mm steel case, a self-winding IWC chronograph movement and sapphire crystal on both sides. Counterfeits copy the outline and use a bought-in movement, a plated case and a printed dial. No counterfeit carries an IWC movement or an IWC case.

What reference IW371620 is

IW371620 sits in the Portugieser Chronograph family, references 3716xx. Published family specs from IWC: 41 mm diameter, 13.1 mm height, steel case, 30 m water resistance, sapphire glass front and back, 46-hour power reserve, 28,800 vibrations per hour. Dial layout is two subdials, small seconds at 6 and a 30-minute counter at 12, with a date window at 3. Dial colour, strap and bracelet vary by reference, so confirm the exact build for IW371620 on IWC's site before you compare a suspect watch.

Where counterfeits differ

Case and finish

Look at the lugs and case flanks under raking light. Genuine IWC brushing runs in one direction per surface, and polished bevels meet brushed faces at a sharp line. Counterfeits show rounded edges, uneven brushing, and polish that bleeds onto brushed areas. Case height is a second tell: fakes built on a thin movement often measure under 13 mm, and fakes built on a 7750 base measure over 14 mm.

Dial and printing

Genuine applied numerals and indices sit in milled recesses. On fakes the indices sit on top of the dial and cast a shadow at the edge. Check the subdial rings for correct spacing, the date window for a sharp frame, and the text under 12 for even stroke weight. Printing on counterfeits smears at 10x magnification.

Movement

Ask for a photo of the movement through the caseback. Genuine 3716 chronographs use an IWC 69000-family calibre with engraving on the rotor and bridges. Counterfeits use third-party chronograph movements, many of them 7750 derivatives, with a rotor stamped or printed to look like IWC. Printed rotor text is a fake part.

Papers and serials

IWC serial numbers are engraved on the caseback, not printed on a sticker. Box, warranty card and manual should match the reference and the serial. Blank warranty cards and cards without a dealer stamp are common in counterfeit sets.

What "first copy" means

"First copy", "mirror quality" and "AAA" are seller terms. No standards body issues these grades. Price tracks movement type: a counterfeit with a quartz or low-grade automatic movement sells under $200, and one with a cloned automatic movement and a steel case runs several hundred dollars. A genuine IW371620 trades in the high four figures, so an offer far below that is a counterfeit or a stolen watch.

Legal note for US buyers

Trafficking in counterfeit goods is a federal crime under 18 U.S.C. 2320. US Customs and Border Protection seizes counterfeit watches at ports of entry, and the buyer loses the watch and the money. IWC does not service counterfeit watches, and many independent watchmakers refuse to open them.

Checks before you pay

  • Caseback photo: engraved serial, correct reference stamp, no sticker.
  • Movement photo: IWC engraving, not printed text.
  • Case height: 13.1 mm on a caliper.
  • Dial photo at 10x: sharp edges on indices and subdial rings.
  • Papers: stamped warranty card that matches the serial.
  • Price: any figure well under secondary market value.