If you are searching for a replica IW371618, you are looking at copies of the IWC Portugieser Chronograph in steel with the blue dial. Short answer: this is one of the harder chronographs to fake well. The dial is wide, flat, and clean, with two subdials stacked at 12 and 6. There is no busy texture to hide behind. Good copies get the silhouette and the color right. Almost all of them miss on case thickness, dial depth, and the movement you see through the back.
What the Real IW371618 Is
The genuine reference is a 41mm stainless steel Portugieser Chronograph with a blue dial, applied numerals, leaf-shaped hands, a date at 3, and sapphire crystal front and back. It runs the IWC calibre 69355 with roughly 46 hours of reserve and carries a 30 meter water resistance rating, which is modest. The watch is about 13mm thick, and that number matters more than any other spec once you start comparing copies.
What Copy Makers Get Right
The case profile, lug shape, and crown are usually close. Dial color on the better blue versions reads convincing indoors, and the printed IWC logo and "Schaffhausen" text are often crisp enough that you would not catch them across a table. The vertical bi-compax layout is easy to replicate because the subdial positions do not depend on the exact movement underneath.
Where Replicas Slip
- Thickness: most copies land around 14.5mm instead of 13mm, and the extra bulk shows at the lugs and under a cuff.
- Subdial depth: on the real watch the snailed rings sit nearly flush. Copies often have flatter or shinier rings.
- Hands: genuine leaf hands are polished and slightly domed. Copies tend to look flat and grey.
- Crystal and coating: weak anti-reflective treatment makes the dial look milky at angles.
- Strap and clasp: the stock alligator-style strap is usually the first thing owners replace.
Movement and Thickness
Here is the useful part. The real 69355 traces back to the Valjoux 7750 architecture, which is also what most copies run in modified form. So the base is not the giveaway. The finishing is. Genuine movements show Geneva stripes, blued screws, and clean perlage. Copies show stamped decoration, rough edges, and a rotor that spins loudly when you move your wrist. A 7750-based chronograph also adds height, which is exactly why the case comes out thicker.
How I Would Check One in Hand
- Measure the case with calipers. Anything past 13.5mm is a tell.
- Start the chrono and reset it. The pushers should feel firm, not mushy.
- Tilt the watch under a lamp and watch the dial go dark instead of white.
- Look at the date font through a loupe. Thin or bold digits show up fast.
- Do not trust the claimed water resistance. Have it pressure tested before it goes near water.
Legal and Practical Reality
Counterfeit watches are illegal to import into the United States, and shipments get seized routinely. There is no warranty, no service network, and most watchmakers will not touch a counterfeit movement. Resale value is close to zero. If the appeal is the look of a Portugieser on a budget, that is a real thing, but go in knowing what you are buying.
Bottom Line
The replica IW371618 gets the shape and color close enough for a casual glance. It does not get the thin case, the dial depth, or the movement finishing. Judge it on those three things and you will not be surprised later.