A fake IW371756 is a counterfeit of the IWC Portugieser Chronograph, the 41mm steel two-register chrono with no date window. The quickest tell is the back. The real watch has a sapphire display case back over IWC's caliber 69355, a column-wheel automatic, and most replicas put something in that window that falls apart under a loupe. Thickness is the second tell, since the genuine case sits close to 13mm while clones tend to run thicker because there is a reworked 7750-family chronograph inside.
What the IW371756 actually is
The 3716 family is IWC's current Portugieser Chronograph, and the last digits of the reference usually point to a dial or bracelet combination rather than a different watch. So an IW371756 shares the platform with its siblings:
- 41mm stainless steel case, roughly 13mm thick
- Bicompax dial: 30-minute counter at 12, running seconds at 6
- No date, applied numerals, leaf-shaped hour and minute hands
- IWC caliber 69355, automatic, column wheel, about 46 hours of reserve
- Display case back with reference and serial engraving on the outer ring
Because the layout is clean, small errors show up fast. A shifted subdial, a date window, or a hand shape that reads slightly heavy are all worth a second look.
The checks I run first
- Turn it over. A 69355 shows a column wheel, Geneva stripes, blued screws, and rotor engraving with real depth. Clones show stamped decoration, flat screws, and rotor text that looks printed.
- Feel the pushers. Column-wheel chronos start and stop with a light, crisp click. A cam-actuated 7750 feels stiffer and mushier at the start.
- Measure the thickness. Anything past 14mm on a steel case is a warning, not proof on its own.
- Check the crown positions. A no-date watch should not have a ghost date click between winding and setting.
- Look at the crystal from an angle. Genuine double-sided anti-reflective coating nearly kills reflections. Single-side coating leaves a blue or purple haze.
Dial and case details
IWC prints and applies markers with tight tolerances. On a fake IW371756, look for hands with lume that sits unevenly in the frames, numerals that look glued on rather than set into the dial, subdial rings that are too thick, and text a hair too bold. The Portugieser dial is flat and matte, so any sunburst or grainy texture on a reference that should not have one is a problem. On the case, check the lug edges and the transition from brushed to polished surfaces. Fakes often polish too much and leave soft edges where the real case has a defined line.
Movement and caseback
This is where the reference is easiest to judge, and also where clone makers spend their effort. Genuine caseback engraving is cut, not printed, so it catches light and has depth. The font is consistent, and the reference and serial numbers match the paperwork. Replicas commonly use acid-etched or laser-marked text that looks flat under magnification, and the placement of the Swiss origin marking can sit slightly off. If a seller will not show a clear photo of the movement through the case back, treat that as an answer.
Strap, bracelet, and hardware
Fake IW371756 listings often get the hardware wrong. On leather, the buckle should be signed and the stitching even. On the steel bracelet, the end links should sit flush against the case with no rattle, and the clasp should close with a solid click rather than a grind. Spring bars, screw heads, and crown engraving are small details that separate a decent replica from a poor one, and they are also what a service center notices within a minute.
Price and paperwork reality
A genuine IW371756 sells in the four-figure range and higher on the secondary market, depending on dial and bracelet. If someone offers one for a few hundred dollars, it is not a bargain. Boxes and papers are easy to fake, so I put more weight on the watch itself and on a service estimate. Sending the watch to an authorized IWC service center is the cleanest test, because a counterfeit gets refused and returned.
Legal note
Importing counterfeit watches into the United States is prohibited, and trafficking in counterfeit goods carries criminal penalties under federal law. That matters if you plan to resell rather than just look.