A fake IW371620 is a counterfeit copy of the IWC Portugieser Chronograph reference IW371620, a steel watch of roughly 41 mm that IWC builds around its in-house column-wheel chronograph movement. People searching this term usually want one of two things: to check whether a watch offered to them is genuine, or to find a replica of that exact reference. The two goals need different checks, so this guide covers both.
What makes the IW371620 worth copying
The Portugieser Chronograph is one of IWC's best-known shapes: a clean dial, thin bezel, two subdials, and a date window at 3 o'clock. Because the design is simple, it is also easier to imitate at a glance than a highly detailed or skeletonized watch. That is why the 3716 family shows up often in counterfeit listings and why the reference number gets searched on its own.
Dial and case tells on a fake IW371620
- Subdial spacing. The genuine layout uses a 30-minute counter at 12 and running seconds at 6. Copies built on third-party chronograph movements often sit the subdials slightly too far apart or too close, which breaks the proportions of the dial.
- Date window. Look at the aperture shape and the font of the numerals. A crisp, correctly sized window with a matching dial finish is a good sign. A rough cut edge or an oversized date font is not.
- Applied markers and hands. The indices should sit level with sharp edges and consistent polishing. Wobbly markers, uneven lume, or hands that do not align with the minute track point to a copy.
- Printing. Text on the dial should be sharp under a loupe, with even spacing. Blurry or thick lettering is one of the easiest things to catch.
Movement tells
The reference uses IWC's in-house calibre 69355, a column-wheel chronograph with a pawl winding system and a power reserve of about 46 hours. Counterfeits usually hide a modified third-party automatic chronograph or, at the low end, a quartz movement behind a decorated plate. Two practical checks: the pusher feel should be firm and defined rather than spongy, and the winding action on a genuine pawl system feels different from a standard oscillating weight. A display caseback matters here, because you can compare what you see with the movement photos IWC publishes for the reference.
Caseback, serial, and paperwork
- Engraving depth and font on the caseback should be clean and consistent, not laser-etched shallow text.
- The reference and serial numbers should match the warranty card, the box label, and any service records.
- Box, booklets, and card quality are easy to fake, so treat them as supporting evidence, not proof.
- Ask for the original purchase date and dealer. A watch with no history is harder to verify.
Buying a replica IW371620 instead
Some buyers are not trying to authenticate anything. They want a wearable lookalike of the Portugieser Chronograph and accept that it is a copy. In that case the sensible approach is the same as any replica purchase: know what you are buying, expect differences in the movement, finishing, and long-term serviceability, and do not pay genuine-watch money for it. Ask the seller what movement is inside, whether the caseback is engraved or plain, and what the return policy is before you commit.
Verify before you pay
- Compare the dial layout against official reference photos of the IW371620.
- Have a watchmaker open the case and identify the movement.
- Cross-check the serial number and service history with an authorized dealer or IWC service center.
- Buy from a seller who accepts returns, whether you want a genuine piece or a replica.
Used together, these checks answer the question fast: a real IW371620 has the right dial proportions, the in-house calibre, and matching paperwork, while a fake IW371620 usually fails at least one of the three.