A fake IW371634 is a counterfeit copy of an IWC Portugieser Chronograph, and it is one of the more common IWC replicas in circulation. The reference number is genuine, which is exactly why it gets copied: the real watch is popular, recognizable, and expensive. If someone offers you an "IW371634" for a few hundred dollars, or at a heavy discount with vague paperwork, assume it is counterfeit until a watchmaker proves otherwise.

Below is what the real reference is, the tells I look for on any 3716, and how to verify one before money changes hands.

What the genuine IW371634 actually is

The IW371634 sits in IWC's Portugieser Chronograph 3716 family. The case is stainless steel, roughly 41mm across and about 13mm thick, with sapphire crystal on both sides and water resistance rated to about 30 meters. Inside, IWC lists the in-house calibre 69355, a column-wheel chronograph with an exhibition caseback, so you can see the movement and rotor through the back.

The dial layout matters for spotting fakes: elapsed minutes sit at 12 o'clock, running seconds sit at 6, and there is no date window. Reference numbers in this family point to specific dial, strap, and bracelet combinations, so confirm the exact configuration in IWC's own catalog before you compare anything. A genuine example runs roughly $7,000 to $8,500 new from a boutique, depending on strap or bracelet.

Why this reference gets faked

The Portugieser Chronograph is a clean, wearable design with an easy-to-photograph dial. That makes it attractive to counterfeiters selling online, where a buyer only sees a few studio shots. Replica factories market these as "super clones" and ship them with copied boxes, warranty cards, and hang tags. The packaging is often more convincing than the watch.

Tells that show up on counterfeit 3716s

The movement

Most fakes of this reference run on an Asian chronograph movement based on the Valjoux 7750 layout or a Seagull chronograph, sometimes with a decorative plate made to look like an IWC finish. The 7750 family stacks its subdials differently, so to mimic the Portugieser layout the maker has to add transfer gearing. That shows up as subdials that sit slightly high or low in the dial, hands that are not perfectly centered in their registers, or a small seconds hand that stutters. Push the chronograph: the real 69355 has a crisp, dry click and the hand snaps back to zero in one motion. A converted 7750 feels spongy and the reset often overshoots or hesitates.

Case and caseback

Look at the lug edges. Genuine IWC lugs have a polished bevel running their length, sitting next to straight, fine brushing. Fakes usually have softer transitions where polish bleeds onto brushed surfaces, and the case sides look slightly rounded rather than crisp. On the back, real engraving is deep and sharp under magnification. Counterfeits often show shallow laser engraving with a faint halo around each letter.

Dial, hands, and subdials

The applied IWC logo on a genuine dial has sharp edges and sits flat against the dial surface. Fakes frequently use a flat printed logo, fuzzy lettering, and printing that is a hair off-center. A date window is an immediate red flag, since this layout has no date. So is any wording that does not match the reference you are told you are buying.

Strap, buckle, and packaging

Genuine IWC leather straps and steel buckles have clean stitching, even thickness, and crisp engraving. Counterfeit straps are thinner, the stitching wanders, and buckle engraving looks buffed out. Fake warranty cards often have no dealer stamp, a serial that does not match the caseback, or a serial that repeats across many listings.

How to verify one before you buy

• Ask for the original receipt and warranty card, then check that the serial matches the caseback and the movement.
• Compare against IWC's catalog photos for that exact reference, not a similar one.
• Have an IWC authorized service center or an experienced watchmaker open the caseback. A service estimate on a counterfeit will be refused, and that refusal tells you what you need to know.
• Weigh it in hand. Counterfeits often feel light or slightly unbalanced compared to the real case.
• Walk away from any seller who will not allow an inspection or who pressures you on time.

What a counterfeit costs you

Trafficking in counterfeit goods carries real legal exposure in the United States, and imported counterfeits are subject to seizure. Beyond the law, a fake has no service support, no parts availability, and no resale value. Water resistance is unverified, which matters if you swim or shower with it. And if you pay genuine money for a fake, you have no recourse with the brand and usually none with the seller.

Quick answers

Is a fake IW371634 worth buying?

Not as an investment and not as a stand-in for the real thing. It cannot be serviced by the brand, it will not hold value, and it carries legal risk if you import or resell it.

What is the single fastest tell?

The chronograph action and subdial alignment. A converted 7750-based fake feels different the moment you press the pushers.