A fake IW371740 is a counterfeit copy of the IWC Portugieser Chronograph, and it gives itself away in four places: dial printing, subdial spacing, chronograph hand reset, and movement finishing. The genuine watch runs an in-house chronograph calibre with column wheel actuation, so a mushy pusher or a sweep hand that creeps back to zero instead of snapping is a stronger tell than any cosmetic flaw.
What Is the IW371740?
The IW371740 is a stainless steel Portugieser Chronograph with a silver plated dial, applied Arabic numerals, feuille hands, small seconds at 6 o'clock, a 30 minute counter at 12 o'clock, and a date window at 3 o'clock. Its case measures about 41 mm across and sits on a black alligator strap with a steel pin buckle.
Because the dial layout is clean and symmetrical, counterfeiters target it heavily. A decent fake photographs well, which is why most bad buys happen online.
What Are the Fastest Visual Tells?
Start with the dial under raking light rather than straight on. Printing quality and applied marker edges separate the real thing from a copy faster than anything else.
- Dial printing: Genuine IWC text is crisp with tight kerning; fakes look slightly bold or fuzzy at the edges, especially the Schaffhausen line.
- Subdial spacing: On the real watch the two subdials sit close to the center with even margins; fakes often push them outward or leave a wide gap.
- Applied numerals: Real markers are thick, faceted and hand-finished. Copies look flat and thin, with soft edges where the facets should catch light.
- Date window: The aperture should have a clean, beveled cut and a font that matches the dial. A stamped square with a chunky numeral is a red flag.
- Hands: Feuille hands should taper to a sharp point and show a mirror polish on the flank. Painted or laser cut hands look dull at the tip.
How Does the Movement Give It Away?
The genuine reference uses an in-house IWC 69000-series chronograph calibre with a column wheel and a vertical clutch, visible through a sapphire caseback. Fakes almost always rely on a modified Valjoux 7750, a clone of it, or a quartz module in cheaper builds.
Two tests do most of the work. Press the start pusher: a column wheel feels light and precise with almost no travel, while a 7750-based fake feels stiff and cammy. Then let the chronograph run a minute and reset it. The genuine sweep hand snaps to 12 with no wobble, while a fake often hesitates, overshoots, or stops a fraction off center.
Look at the movement through the caseback. Real IWC finishing is Geneva stripes with polished bevels and deep engraving on the rotor. Copies show shallow laser etching, flat screws, and a rotor that looks stamped rather than machined.
What Do Counterfeit Quality Tiers Look Like?
Fakes of this reference fall into three rough groups: quartz models with a faux chronograph, 7750-based automatics with a correct layout but crude finish, and higher end copies that mimic the dial closely while still using a third-party movement.
None of them match the genuine article, and the top tier costs enough that buyers often wonder why they did not save for a used original. That gap widens every year as genuine steel chronographs hold value.
How Can You Verify One Before Buying?
- Ask for a short video of the chronograph starting, stopping and resetting to zero.
- Request macro photos of the dial text, the caseback engraving and the movement.
- Check the serial against IWC service records, and ask for the warranty card with a matching number.
- Have a watchmaker read the rate on a timing machine; a genuine in-house calibre holds steady amplitude.
Frequently Asked Questions
Is the IW371740 faked often?
Yes. The Portugieser Chronograph is one of the most copied IWC lines because its dial is simple enough to print and popular enough to sell quickly.
Can any watchmaker spot a fake instantly?
Usually. A trained eye checks the movement finish and pusher feel before the dial, since those are the hardest details for counterfeiters to replicate at a low price.
Does a box and papers prove authenticity?
No. Packaging is easy to copy and often sold separately. Treat documents as one data point and confirm the serial with IWC directly.