Short answer
Most fake IW371704 watches fail four checks: the movement, the subdial layout, the dial printing, and the caseback engraving. A genuine Portugieser Chronograph runs IWC Calibre 69355 in current production, or Calibre 79350 in older references. Counterfeits run a stock Valjoux 7750 or a Chinese clone. That difference shows on the dial as a running seconds hand at 9 o'clock, and it shows in the pusher feel and the date change.
Where to Buy Fake IW371704: Buying Guide
Confirm the reference first
The Portugieser Chronograph line uses one 41 mm case across many references. Dial color, indexes, hands and strap change from reference to reference. Pull up the IW371704 entry in IWC's catalog and note the dial, the case material and the strap. A seller who describes a dial that does not match the reference is a seller to walk away from.
Fake IW371704 Price Comparison: Buyer's Guide
Movement
- Genuine: IWC Calibre 69355, automatic, column wheel, 46 hours of power reserve, 28,800 vph. Earlier references use Calibre 79350, a Valjoux 7750 base modified by IWC.
- Counterfeit: an unmodified 7750 or a clone. Look at the subdial at 9 o'clock. On a stock 7750 that subdial holds the running seconds. On the Portugieser layout the running seconds sit at 6 o'clock and the 12 o'clock subdial counts 30 minutes.
- Check the calibre number on the bridge and the rotor signature. Fakes often carry no calibre number, or a stamped number in place of engraving.
Dial and hands
- Subdials at 12 for the 30-minute counter and at 6 for small seconds. Date window at 3.
- Printing: IWC and SCHAFFHAUSEN. Look at the edge of each letter under magnification. Genuine printing has sharp edges. Fake printing shows a dot pattern from pad printing.
- Hands: compare shape, polish and length against the catalog photo for the reference. Fake minute hands often stop short of the minute track.
Case, crystal and strap
- Case: 41 mm wide. IWC lists the height and the water resistance for the reference. Confirm both in the catalog. The flanks are brushed, the bezel and lug tops are polished. On fakes the line between the two finishes is blurred.
- Crystal: sapphire with anti-reflective coating on both faces. A fake often uses mineral glass, which scratches and reflects more.
- Strap and buckle: alligator with hand stitching on genuine pieces, IWC-signed pin buckle or deployant. Fakes use embossed calf and a blank buckle.
Caseback and numbers
Genuine casebacks carry cut engraving for the reference, the case number and SWISS MADE. Stamped or laser-printed markings with shallow edges point to a copy. The reference on the caseback must match the reference on the papers. IWC's service center can check a case number against its records.
Best Fake IW371704 Watch: Tier-by-Tier Replica Review
Checks to run before you pay
- Ask for the reference and case number, then compare both to the catalog.
- Ask for a clear photo of the caseback and a photo of the movement with the back removed.
- Ask for a video of the chronograph start, stop and reset, plus the date change at midnight.
- Take the watch to a watchmaker and have the case opened. Check the calibre number, the rotor and the finish.
- Compare weight and pusher feel against a known genuine watch.
Price and paperwork
A new steel Portugieser Chronograph sells at authorized dealers in the high four figures USD. Check the current figure with IWC. A watch described as new and offered at a fraction of that price is not genuine. Papers, box and a My IWC registration help, but documents can be copied, so they prove nothing on their own. The watch itself is the evidence.