A fake IW371438 is a counterfeit of the IWC Portugieser Chronograph ref. IW371438, the 40.9 mm steel two-register chronograph from the ref. 3714 family. The real watch runs IWC caliber 79350, a heavily reworked Valjoux 7750, and it is one of the most copied IWC references around. That detail cuts both ways. Because the original is built on a common chronograph base, the movement alone proves almost nothing, so authentication comes down to caseback engraving, dial printing, pusher feel, crown detail and overall finish.
What the genuine IW371438 actually is
Before you can judge a copy, you need the target in your head. The ref. 3714 Portugieser Chronograph is a round steel case of roughly 40.9 mm across and about 12.6 mm thick, with a silvered dial, applied numerals, a small seconds subdial at 6 o'clock, a chronograph minutes counter at 12 and a date aperture at 3. Inside sits caliber 79350, beating at 28,800 vph with a power reserve in the mid 40 hour range. Sapphire crystal front and back, a display caseback, and water resistance rated at a modest 30 m. The reference number is engraved on the caseback and appears on the paperwork and hang tags.
Where replicas give themselves away
Caseback and engraving
Factory laser engraving is shallow, even and crisp. Fakes tend to show rounded letter edges, uneven spacing, a reference number in the wrong font, or a caseback that feels thin when you tap it. On a display back, look at the movement: real caliber 79350 has clean perlage, distinct Geneva stripes and a rotor engraved with sharp, fine text.
Dial and printing
Get close. Genuine dial text is razor sharp under a loupe, the applied numerals sit flat with tight feet, and the subdial rings are cleanly recessed. Copies show fuzzy print, slightly fat numerals, or subdials placed a hair off center. The date font is another tell: genuine IWC date wheels use a specific typeface, and most replicas use a generic one.
Pushers and crown
Press the chronograph pushers. The real 79350 has a firm, mechanical click with a short throw. Cheap clones feel mushy, gritty or spongy, and the reset can be soft or sticky. The crown should turn smoothly, screw down without cross threading and carry a well defined IWC logo with a crisp edge.
Weight and feel
A steel case should have heft. Replicas frequently use lighter alloys, a thinner caseback, or a hollow feeling bracelet with stamped end links and sloppy tolerances at the lugs.
Why this reference gets copied so hard
The 3714 has a clean, symmetrical dial that is easy to print, a case shape that is simple to machine, and enough brand recognition to sell. It is also expensive enough on the secondary market that a counterfeit at a low price looks tempting to someone who does not know the reference well.
How to verify before you buy
- Ask for a clear macro photo of the caseback, including the reference number between the lugs.
- Request a movement shot with the rotor text legible.
- Compare dial text and numeral shapes against official IWC reference photography.
- Check the serial and reference against the warranty card and box.
- Meet a watchmaker for a timing check and a look at the movement finish.
- Treat any deal far below market as a warning, not a bargain.
Bottom line
No single photo proves an IW371438 is real. The dial, the caseback, the engraving, the pusher action and the movement finish each carry weight. Stack several checks together and a fake usually stops looking convincing quickly.