Short answer

A replica IW371756 is a copy of an IWC Portugieser Chronograph. The genuine watch is a 41 mm steel chronograph with two subdials, a date at 3 o'clock and caliber 69355. Good copies match the case shape, the dial layout and the handset. Most fail on case thickness, subdial function and movement type. Ask for a caseback photo and a movement photo before you pay.

Reference notes

IWC reference numbers for the Portugieser Chronograph run in the IW3714 and IW3716 blocks. Published spec sheets for the exact number IW371756 are thin. Confirm dial color, case metal and strap from seller photos. If the listing shows stock images only, treat the reference as unverified.

What the genuine watch does

  • Case: 41 mm diameter, about 13 mm thick, stainless steel
  • Movement: caliber 69355, in-house, column wheel, 4 Hz, 46 hours of reserve
  • Layout: small seconds at 6, chronograph minutes at 12, date at 3
  • Crystal: sapphire front, sapphire caseback
  • Water resistance: 30 m
  • Lug width: 20 mm

Points to inspect on a copy

  1. Case thickness. Copies built on a 7750 base run 14.5 mm or more. The genuine case sits near 13 mm. Ask for a caliper photo.
  2. Subdial function. On low-tier copies the counter at 12 is decorative or reads 30 minutes instead of 60.
  3. Date window. Check the frame cut, the font weight and the gap to the 3 o'clock marker.
  4. Dial print. The brand name and "SCHAFFHAUSEN" should sit sharp under a loupe, with no ink spread.
  5. Hands. Leaf shape, clean center line, no burr at the tip.
  6. Caseback. Sapphire, engraved reference digits and a serial. The digits must match the listing.
  7. Strap and buckle. Alligator grain, 20 mm at the lugs, signed pin buckle.

Movement check

Ask for a photo of the movement through the caseback. A 7750 clone shows a single rotor screw and coarse perlage on the bridges. A clone of the 69355 shows a column wheel near the balance and a wider bridge shape. If the seller lists an Asian 7750 and a 13 mm case in the same listing, the numbers do not match.

Red flags

  • Stock photos with no caseback image
  • No measurement table for diameter and thickness
  • Claims of a perfect match with no movement photo
  • Price far below the tier the seller claims

What a copy cannot match

The 69355 uses a column wheel with a vertical clutch. Most copies use a cam and an oscillating pinion, so the pusher feel is heavier and the chronograph seconds hand can jump at start. Bridge finishing on copies is machine-applied. Anglage and black polish are absent. Rotor winding feel differs. None of these faults show in a photo at arm's length, but all of them show in the hand.

Cost and tiers

Low-tier copies sell for about $100 to $200 and show a thick case and printed subdials. Mid-tier copies run $250 to $450 with a working chronograph. Top-tier copies start near $500. Prices move with the seller and the batch, so treat these numbers as a range, not a quote.