Short answer

IW371747 is an IWC reference in the Portugieser Chronograph line. Replica versions sell from about $250 to $900. Three checks separate a good copy from a weak one: case thickness, subdial position, and crystal coating. Confirm the dial and strap of the exact reference you want before ordering, because IWC uses the final digits of a reference number to mark dial and strap variants.

What the reference covers

The Portugieser Chronograph is a steel watch, about 41 mm wide and about 13 mm thick, with sapphire crystal on the front and the back, water resistance rated at 30 m, and an alligator strap with a folding clasp. The dial carries two subdials: running seconds at 6 o'clock and chronograph minutes at 12 o'clock. A date aperture sits at 3 o'clock on most versions.

The current movement is an automatic IWC caliber with a power reserve of about 46 hours. Older production used a different chronograph base. The reference suffix matters here: two watches with the same movement can differ in dial color, hand finish, and strap.

Replica tiers and prices

  • Entry tier, about $250 to $400: quartz or a basic chronograph copy, mineral glass or low-grade sapphire, stamped clasp, flat dial printing.
  • Mid tier, about $400 to $650: modified chronograph movement with a transfer plate that moves the running seconds to 6 o'clock, sapphire with single-side anti-reflective coating, closer dial print.
  • Top tier, about $650 to $900: decorated movement, correct subdial spacing, double AR coating, leather or alligator strap, engraved caseback.

The transfer plate in mid-tier and top-tier chronographs adds mass. That extra plate is the main reason replica case height lands at 14 mm to 15 mm instead of 13 mm.

Tells to check

  1. Thickness. Ask the seller to place calipers on the case and photograph the readout.
  2. Subdial position. Running seconds must sit at 6 o'clock, not 9 o'clock. A seconds hand at 9 is a stock chronograph layout, not the Portugieser layout.
  3. Crystal. The original has anti-reflective coating on both faces. A single-side coating throws a blue or green tint at an angle.
  4. Dial printing. The brand name and city name use fine, even strokes. Applied numerals stand above the dial surface and catch light on their edges.
  5. Date window. Check the aperture cut, the frame finish, and the date font.
  6. Caseback. Engraving should list the reference, the case number, and the model name. Shallow laser etching is a sign of a low tier build.
  7. Strap and clasp. Stitching density and clasp spring tension are easy to compare in photos.

Pre-purchase checklist

  1. Request daylight photos and one angled photo of the dial.
  2. Request a movement photo with the caseback removed.
  3. Ask which movement is inside and whether a transfer plate is used.
  4. Confirm the return window and the refund path in writing.
  5. Check the stated case diameter and thickness against the numbers above.

What is not known

IWC does not publish a public archive of every reference suffix, so some dial and strap combinations for this reference cannot be confirmed from open sources. Most replica sellers do not name the movement base or the plate design. Ask for both in writing before payment.