A fake IW371650 is a replica of the IWC Portugieser Chronograph, a round steel chronograph with a two-register dial and an in-house automatic movement. The fastest way to separate a replica from the genuine reference is to check the dial layout and printing, the case thickness at the lugs, and the movement finish visible through the sapphire caseback.
What the IW371650 actually is
The reference belongs to the Portugieser Chronograph family, a line known for a clean, wide dial with slim bezel and thin feuille hands. The genuine watch uses a steel case of roughly 41 mm, a sapphire crystal with anti-reflective coating on both sides, and a display back. Power comes from an in-house automatic chronograph calibre, finished with Geneva stripes and a signed rotor.
That combination is what makes it popular with counterfeiters. The design is simple enough to copy at a glance, but the finishing standards are hard to match at a low price. That gap is where most fake IW371650 watches give themselves away.
The details that separate real from fake
Case and proportions
- Genuine cases sit slim on the wrist. Many replicas are 1 to 2 mm thicker because the movement inside is deeper than the original calibre.
- Look at the lug profile. Original lugs curve down and taper; cheap copies keep them blocky and flat.
- Polished and brushed surfaces should meet in one crisp line. On fakes, the transition often wanders or shows a rounded edge.
Dial and hands
Dial printing is the single most reliable tell. Genuine text is applied or printed with sharp edges, even spacing and consistent weight. Replicas show thick letters, uneven gaps and script that looks slightly squeezed. The two subdials should be perfectly aligned on a vertical axis, with their snailed rings cut evenly and the needle hands sitting flush to the surface. Applied numerals on the original have polished bevels that catch light; copies usually look flat.
Crystal, caseback and engraving
The sapphire crystal on the real watch has a slight dome and a clear AR coating that kills reflections at an angle. Replica crystals often look cloudy or show a strong blue or purple tint. Flip the watch over: the reference and serial engravings on the genuine caseback are laser cut with sharp walls, while copies are shallow and slightly blurred.
Movement
This is the hardest part to fake well. The authentic watch runs an in-house chronograph calibre with striped bridges, blued screws and a decorated rotor. Many replicas use a generic chronograph module with a plain rotor, rough perlage and visible machining marks. Wind it and start the chrono: the genuine pushers have a firm, short travel, while copies feel mushy or click twice.
Strap, buckle and packaging
Original straps are alligator with tight, even scales, a soft backing and clean stitching at the lugs. Replica straps are often embossed calf leather with a plastic feel. Buckle engraving on the real piece is deep and centered; on copies it is light and off-center. Packaging is easy to counterfeit, so treat a box and papers as a supporting detail, not proof.
Why the dial layout matters most
Before you judge any single detail, compare the watch against photos of the exact reference you are checking. Minor variations exist between reference numbers in the Portugieser Chronograph range, so a difference in date placement, subdial spacing or hand shape only counts as a tell when you are comparing like with like. Once you have the correct reference image side by side, layout errors jump out immediately.
Quick inspection checklist for a fake IW371650
- Measure the case thickness against the published dimension for the reference.
- Check subdial alignment with a straight edge across the dial.
- Look at printing at 2x magnification for jagged or heavy letters.
- Tilt the crystal toward a light source and watch for cheap AR tint.
- Read the caseback engraving depth and the spacing between characters.
- Inspect movement finishing and rotor engraving through the display back.
- Compare pusher feel and reset snap when the chronograph returns to zero.
What to remember before buying
A replica is not a genuine IWC and should never be sold or represented as one. If you are buying a copy knowingly, judge it as a copy: ask for close-up photos of the dial, caseback and movement, request the measured thickness, and buy from a seller who answers technical questions instead of only sending marketing shots. Sellers who hide the movement or refuse a photo of the caseback are the ones you walk away from.