The IW371493 sits in the IWC Portugieser Chronograph family, a two-register chronograph with a 41 mm case. A counterfeit is a watch built to copy that dial and case. Three checks catch most copies: case thickness, the position of the two subdials, and the movement visible through the caseback. IWC does not publish a separate spec page for every Portugieser reference, so confirm the exact case size, dial color, and calibre with IWC or an authorized dealer before you pay.
Case and crystal
The genuine Portugieser Chronograph measures 41 mm across and about 13 mm thick. Sapphire covers the front and the back. Water resistance is 30 m. Copies run large: 42 mm to 44 mm wide and 15 mm thick or more. Ask the seller for caliper photos of the case, not wrist shots.
- Crystal: genuine sapphire carries a double anti-reflective coating. Mineral glass with a blue or purple tint shows up on copies.
- Bezel: polished, even width around the dial. Copies show a wide or uneven bezel ring at the 12 and 6 positions.
- Crown: seats flush against the case tube. A gap of 1 mm or more points to a replacement part.
Dial and subdials
The dial layout is the fastest tell. Chronograph minutes sit at 12 o'clock. Running seconds sit at 6. If the seconds hand runs at 9 o'clock, the watch uses a stock Valjoux 7750 layout and does not match the reference.
- Text: "IWC" and "Schaffhausen" print on two lines above the center. Copies use heavier strokes and wider letter spacing.
- Numerals: applied and faceted on the genuine dial. Copies use flat stamped markers that sit on the surface.
- Hands: leaf-shaped, heat-blued or polished steel, with a clean edge. Copies show burrs and paint edges.
Movement
Current Portugieser Chronograph models run the IWC calibre 69355, an in-house column-wheel chronograph. Power reserve is 46 hours at 28,800 vibrations per hour. Earlier IW3714 references used calibre 79350, a Valjoux 7750 base with cam switching and a 44-hour reserve.
Check through the caseback: Geneva stripes on the bridges, polished bevels, an engraved rotor, no plastic movement ring. A 7750-style rotor with a single screw and rough perlage appears in most copies. Press the top pusher. A column wheel starts clean and light. A cam-switched movement kicks back against your thumb.
Engraving, serial, and papers
The caseback carries the reference number, the serial number, "Sapphire crystal", the water resistance rating, and "Swiss Made". Engraving on the genuine case is deep and sharp. Copies show shallow laser etching with rounded edges. IWC can confirm a serial number against its records. A warranty card that cannot be registered through IWC's owner portal is a blank card.
Price and seller checks
IWC sells steel Portugieser Chronograph models in the high four figures to low five figures USD. Used examples trade below retail. A listing at $300 to $900 for a watch with box and papers does not match any market. Buy from a seller who accepts a return, provides a movement photo, and matches the serial number to the caseback and the papers.
No single check is proof. Two or three mismatches together are enough to walk away.