Short answer

The IW371431 is a reference in the IWC Portugieser Chronograph line, family 3714. A fake IW371431 is a copy of that watch. Copies sit in four grades: quartz, entry automatic, mid-tier automatic, and super clone. The case shape, dial layout and subdial placement are easy to match. The movement, the caseback engraving and the crystal coating are not. Asking prices run from about 60 USD to 900 USD depending on grade.

Genuine IW371431 specs

  • Case: stainless steel, 40.9 mm diameter, 12.3 mm thick.
  • Movement: IWC caliber 79350, automatic, base Valjoux 7750, 28,800 vibrations per hour, 44 hours power reserve.
  • Functions: hours, minutes, small seconds at 6, chronograph with 30-minute counter at 12, date at 3.
  • Crystal: convex sapphire with anti-reflective coating on both faces. Sapphire caseback.
  • Water resistance: 3 bar.
  • Strap: alligator leather on a steel pin buckle or folding clasp.
  • Production: the 3714 family ran from 1998 to 2020. Ref 3716 replaced it with the in-house caliber 69355.

IWC built several dial and strap versions inside the 3714 family. Confirm the exact dial color, hand plating, case metal and strap for IW371431 against a reference database or the manufacturer catalog before you compare a copy to it. The specs above cover the family, not every variant.

Tells on a fake

  • Caseback engraving: shallow laser marks with soft edges. Genuine engraving has depth.
  • Reference digits: copies often carry a number that does not match the dial and case combination.
  • Thickness: measure with calipers. Copies built on a 7750 base run 13.5 mm to 14.5 mm.
  • Subdials: a quartz copy puts the small seconds hand on a one-tick-per-second sweep.
  • Crystal: weak or missing coating. Reflections look gray instead of blue.
  • Pushers: soft travel, no click on start. A 7750 pusher feels firm.
  • Rotor: printed text, not engraved and filled. Wrong screw heads.
  • Dial font: the date wheel and printed numerals differ in weight and spacing.
  • Strap: embossed cowhide sold as alligator.

Replica grades and prices

  • Quartz: 60 to 120 USD. Wrong thickness. No working chronograph, or a fake one.
  • Entry automatic: 150 to 300 USD. Asian 7750 copy, 21,600 vph, correct subdial layout.
  • Mid-tier: 300 to 500 USD. Cleaner case finishing, sapphire crystal, decorated rotor.
  • Super clone: 500 to 900 USD. Case dimensions close to original, 28,800 vph, cloned 79350 plates.

Prices move with seller, currency and shipping. Treat any range as a starting point.

Checks before you pay

  1. Ask for a photo of the caseback with the reference number readable.
  2. Ask for a side profile photo with calipers in frame.
  3. Ask for a timegrapher reading: rate, amplitude, beat error.
  4. Ask for a video of the chronograph start, stop and reset.
  5. Get the return policy in writing.
  6. Pay with a method that has a dispute process.

What no copy matches

Movement finishing. IWC decorates the 79350 with stripes, blued screws and a signed rotor. Copies use printed plates or thin plating. Service support. A watchmaker can order Valjoux 7750 parts. Parts for a cloned movement come from the seller. Resale. A genuine 3714 holds value on the secondary market. A copy does not. Warranty. IWC offers a multi-year warranty. Replica sellers offer 6 to 12 months at best.