A fake IW3717 usually fails at the dial and the caseback before it ever fails at the movement. The genuine IWC Portuguese Chronograph reference 3717 has a 40.9 mm case, applied numerals on a sharply printed dial, two subdials stacked at 12 and 6, and a solid caseback with deep engraving. Replicas most often slip on case thickness, the finish of the applied numerals, and the crispness of the caseback text.
What is the IW3717 and why is it copied so often?
The IW3717 is IWC's Portuguese Chronograph Automatic, a 40.9 mm steel chronograph built around caliber 79320, a 28,800 vph automatic with about 44 hours of power reserve. Its clean two-register dial makes it one of the most photographed watches in the brand's lineup. That same simplicity is what attracts replica makers, because a bad copy still looks convincing at arm's length.
How can you tell if an IW3717 is fake?
Work through the checks below in order. The first four cost nothing and catch most replicas.
1. Measure the case
Genuine IW3717 cases measure 40.9 mm across, excluding the crown, and sit roughly 12 mm thick. Many replicas run a half millimeter to a full millimeter thicker because of a thicker movement spacer. Calipers settle this faster than a photo.
Fake IWC 3717 US Guide: Buying a Portuguese Chronograph Replica
2. Study the dial printing and applied numerals
- Numeral edges should be sharp and evenly polished, with no rounding or soft corners.
- The IWC wordmark and Schaffhausen sit level, printed with clean unbroken strokes.
- Subdial hands should reach the exact hash marks; short or long hands are a common flaw.
- Subdials must sit at 12 and 6, never at 9 and 3.
3. Check the caseback engraving
Genuine engraving is cut deep, with crisp inner corners and consistent font weight. Replicas typically show shallow laser etching, soft edges, and a serial number that does not match the papers. Compare the reference stamped on the back against the warranty card and the invoice.
4. Confirm the layout against the exact reference
Details changed across the 3717 run, including the date aperture on some variants and the small dial text. Pull the exact reference number and compare photos of a known genuine example instead of relying on memory.
5. Open the caseback
Caliber 79320 is a modified Valjoux 7750 base, so it shows classic cam and lever chronograph works and a rotor that rocks slightly when you tilt the watch. A clone 7750 can imitate that feel, so the real test is the rotor engraving, balance bridge, and finishing under a loupe. This step needs a watchmaker, and it is the only one that ends the argument.
6. Weigh the price and the paperwork
Complete, serviced examples trade in the mid four figures in the US market. A mint-looking IW3717 offered at a third of that price answers your question on its own.
Can photos alone prove an IW3717 is genuine?
No. High-end replicas clear most photo checks, and sellers know which angles to shoot. Photos can rule a watch out, but only an in-person or bench inspection can rule one in.
What should you do before you pay?
- Ask for the reference and serial, then verify them against the card and any service receipt.
- Request a short video of the chronograph starting, stopping, and resetting cleanly to zero.
- Meet at a watchmaker, or use an escrow service with a return window.
- Pay with a method that can be reversed if the watch fails inspection.
Is buying a replica IW3717 legal in the US?
No. Selling or trafficking counterfeit goods is illegal under US trademark law, and US Customs and Border Protection seizes counterfeit watches at import. Buyers also lose any recourse when the watch arrives broken or is not what the listing showed.