Short answer
Most fake IWC Portugieser Chronograph watches sold as reference IW371422 fail three checks: the caseback engraving, the gap between the subdials and the printed track, and the finishing on the movement. On a genuine watch the reference and serial numbers are engraved in a thin, even font along the caseback edge, and that serial can be verified through the brand's owner portal. If a seller cannot show both numbers matching on the watch and on the paperwork, stop there.
What the genuine reference should look like
The IW371422 belongs to the Portugieser Chronograph family: a stainless steel case of roughly 41 mm, sapphire crystal front and back on later examples, two chronograph counters stacked at 12 and 6 o'clock, and a printed minute track that follows the subdial rings. Later versions of this reference run IWC's in-house calibre 69355, a column-wheel chronograph with a 46 hour power reserve. Earlier Portugieser Chronograph cases carried the 79350, which is a reworked Valjoux 7750. That split matters, because fakes often pair the wrong movement family with the wrong caseback text.
Prerequisites
- A 10x jeweler's loupe
- Digital calipers
- Catalog photos of the exact reference on a second screen
- Even daylight, with no flash glare on the crystal
How to check a watch step by step
- Ask for a close photo of the caseback edge, then compare the reference and serial digits with the warranty card and the box label.
- Measure the case with calipers and compare the diameter and thickness against the official figures.
- Start the chronograph and watch the minute counter for eight minutes to see whether it jumps in clean one minute steps.
- Inspect the subdial spacing, where the printed track should meet each subdial ring with no gap and no overlap.
- Read the dial printing under the loupe, checking that the IWC wordmark and the Schaffhausen line sit level and evenly weighted.
- Examine the hands for a crisp center crease and for paint bleed at the tips.
- View the movement through the display back and confirm the rotor engraving, the balance frequency and the column wheel.
- Wind the watch fully and let it run for a day against a phone clock to check the rate.
- Have the serial verified by a service center or authorized dealer before money changes hands.
Replica versions you will meet
Two tiers appear under this reference. Low grade copies use quartz or a rough mechanical movement, and the case runs too thick while the counters sit flat against the dial. Higher tier copies clone the Valjoux 7750 and get the dial close, but the bridge decoration, the balance spring shape and the engraved caseback text still give them away. Request an angled movement photo, since sidelight exposes finishing flaws that a straight shot hides.
Price and seller checks
A full set offered far below the normal pre-owned range is the single strongest signal of a fake. Meet at a dealer or an independent watchmaker when you can, pay with a method that leaves you a dispute route, and keep every message and photo from the seller.