Fake IW371771 is the shorthand buyers use for replica versions of the IWC Portugieser Chronograph built around the 3717 reference family. A replica of this watch is normally judged on four points: the movement inside, the case proportions, the dial printing, and the finish on the strap or bracelet. None of that makes the watch a genuine IWC, and a replica should never be sold or passed on as authentic.
What the IW371771 Reference Refers To
IWC reference numbers follow a pattern. The core number identifies the model family, and the trailing digits identify a specific case metal, dial color, and strap combination. So a code such as IW371771 points to one particular configuration inside the Portugieser Chronograph line, not to a separate watch design. That matters when you shop, because two replicas can share a case shape but differ in dial layout, hand style, and caseback treatment.
The original design is a two-register chronograph with a clean, wide dial, applied numerals, and a slim bezel. Replica makers copy the silhouette first and the details later, which is why proportions are usually closer than dial text.
Movement: The Biggest Difference
The genuine watch uses an IWC chronograph caliber. Most replicas use a Valjoux 7750 based automatic, or a decorated copy of it. Ask what is inside and expect one of these answers:
- Asian 7750 automatic, the most common option in mid tier replicas.
- Swiss 7750 or a Swiss parts build, offered at a higher price.
- A clone movement made to look like the IWC caliber, usually with decorative plates and engraving.
Function checks are simple. Start the chronograph, run it for ten minutes, and reset it. The hands should snap back to zero together. The rotor should spin without grinding, and the winding should feel smooth rather than gritty.
Case, Crystal, and Finish Checks
- Thickness. The genuine Portugieser Chronograph is roughly 12.5 to 13 mm thick. Many replicas run 14 mm or more because of the movement and spacer ring.
- Diameter. Expect about 41 mm. Measure it with calipers if a seller quotes a precise number.
- Crystal. Look for a domed sapphire with anti reflective coating on both faces. A cheap single sided coating shows glare at an angle.
- Caseback. Engraving should be crisp and centered. Depending on the version, some have a display back and some are solid.
- Bracelet and strap. Leather should be stitched evenly and taper cleanly. Metal bracelets should not rattle or catch on skin.
Dial and Subdial Details
Subdial spacing is the tell most people miss. On a 7750 based replica, the subdials sit slightly closer together than on the genuine layout. Check the printing under a loupe: the brand text, the numerals, and the minute track should be sharp with no bleed. Date windows should be centered vertically in their aperture and the date font should not look thin or generic. Hands should be polished on the bevels and flat on the top surfaces.
Questions to Ask Before Buying
- Which movement is inside, and is it serviced or new?
- What are the measured diameter and thickness?
- Can you send photos of the actual watch, not catalog images?
- Is the crystal sapphire, and does it have double sided coating?
- What is the return policy if the chronograph does not reset to zero?
Ownership and Care Notes
Treat a replica like any mechanical chronograph. Keep it away from strong magnets, avoid pressing the pushers underwater, and have the movement cleaned every few years if you wear it often. Store it on a soft surface so the crystal does not pick up scratches. Be clear with yourself and anyone else that the watch is a replica, because selling it as a genuine IWC is a legal problem, not just an ethical one.