Fake IW371615: The Short Answer

A fake IW371615 almost always fails on the small things a factory cannot copy at low cost. Look at the dial print under magnification, the subdial spacing, the caseback engraving, the crown action, and the movement through the sapphire back. If the watch has a solid caseback, or the chronograph pushers feel mushy, treat it as counterfeit until proven otherwise. The real reference runs an in-house calibre with a column wheel, so the pusher stroke is crisp and the seconds hand sweeps from a running small seconds subdial at 6 o'clock.

What the Genuine Reference Looks Like

The IW371615 is a stainless steel Portugieser Chronograph with a blue dial, rhodium-plated hands, a 41 mm case, and a display back. Match these traits first, because most fakes are built from a generic case that is either too thick or too wide.

  • Case diameter near 41 mm with a slim, flat bezel
  • Blue dial with applied numerals, not printed ones
  • Small seconds at 6 o'clock, chronograph minutes at 12 o'clock
  • Sapphire crystal front and back
  • Alligator strap with a signed pin buckle
  • Water resistance rated at 3 bar

Step-by-Step Checks

  1. Measure the case with calipers. Anything past 41.5 mm or thicker than 13 mm is suspect.
  2. Study the dial print with a 10x loupe. Genuine text sits sharp and level, with no ink bleed or uneven letter spacing.
  3. Check the subdial position. The small seconds hand must sit at 6 o'clock and the chronograph minute counter at 12 o'clock, spaced apart in the classic Portugieser layout.
  4. Press the chronograph pushers. Real ones have a short, clean travel with no grinding, because the column wheel controls the start, stop, and reset.
  5. Turn the crown. It should wind smooth, with a firm click when you set the date and hack the seconds.
  6. Inspect the caseback engraving. Reference number, serial, and IWC branding are laser cut deep and even, never shallow or dot-matrix printed.
  7. Look at the movement. Fakes often hide a stock chronograph module under a decorated plate, so compare the balance wheel position, the rotor engraving, and the finishing to owner photos.
  8. Check the lugs and spring bars. Sharp edges and oversized lug holes point to a generic case.
  9. Weigh the watch. A real steel Portugieser on leather sits in a narrow weight band, and fakes usually run light or heavy.

Where Counterfeits Fail Most

Dial printing is the first tell. Copy houses get the shape right and the lettering wrong, so the IWC logo looks thick, the numerals sit slightly off center, and the word Portugieser loses its spacing.

The second tell is the movement. A genuine calibre shows Geneva stripes, blued screws, and a signed oscillating weight. A fake shows a plain rotor, a plastic spacer ring, or a movement that does not match the reference at all.

The third tell is the paperwork. Box, booklet, and card should carry a matching serial and reference. Mismatched numbers are a hard stop.

Buying Used: Verify Before You Pay

  1. Ask for a photo of the caseback and the movement, not just the dial.
  2. Request the serial and reference in writing before you send money.
  3. Meet at a watchmaker or an authorized service center for an opening inspection.
  4. Pay with a method that allows a chargeback if the watch fails inspection.
  5. Walk away if the seller refuses an inspection or pushes for a fast wire transfer.

When to Walk Away

A price far below market for a steel Portugieser Chronograph is the loudest warning sign. Factor in a service quote before you buy, because a counterfeit cannot be serviced by IWC and has no resale value. If any check in this guide fails, stop and get a second opinion from a watchmaker who handles IWC.