If you are looking at an IW371743 and the price sits far below the going rate for a genuine IWC Portugieser Chronograph, treat the watch as counterfeit until the movement proves otherwise. The dial is the easiest part of this design to copy and the least useful place to look. The decisive test is what sits behind the sapphire caseback: the caliber, the finish on the bridges and rotor, and whether the chronograph is driven by a column wheel. Buy from an authorized dealer, a seller with verifiable history, or a watch that has been authenticated by an IWC service center. Walk away from any deal that leans on urgency, a wire transfer, or a story about why the papers are missing.

What the IW371743 reference is

The reference belongs to the IWC Portugieser Chronograph line, a family built around a large, uncluttered dial with two subdials, applied indices, and leaf-shaped hands. Because the design is restrained, it photographs well and copies badly in person. Before you compare anything, pull the official specification for the exact reference from IWC and note the case diameter, case height, lug width, water resistance, and caliber number. Almost every counterfeit falls outside at least one of those numbers, and sellers rarely check.

Why this model gets faked so often

The exterior is simple geometry: a round case, a flat dial, two subdials, no complications beyond the chronograph. That makes the outside cheap to reproduce. The inside is the opposite. A genuine column-wheel chronograph movement requires tight tolerances, proper finishing, and a level of assembly that copy shops do not attempt, so most fakes hide a stock chronograph base under a decorated rotor and hope nobody looks closely.

How to tell a fake IW371743 from a genuine one

Movement and caseback view

Ask for sharp, well-lit photos of the movement before anything else. On a real watch you should see clean Geneva stripes, crisp engraving on the rotor and bridges, blued or polished screws with intact slots, and a column wheel visible when the chronograph is engaged. Fakes show shallow surface decoration, laser etching that looks flat, screws with chewed heads, and a rotor that spins with a tinny rattle.

Dial, hands, and subdials

Genuine printing is razor sharp under magnification, with even spacing and no ink bleed. Copy dials show fuzzy text, uneven lume fill, indices that sit slightly crooked or proud of the surface, and hands with dull edges where the polishing should catch light. Check the subdial spacing and the date window position. Subdials placed a fraction off center are a strong sign of a stock movement that does not match the original layout.

Case, crown, and pushers

Run a fingernail across the transition between brushed and polished surfaces. On a genuine case the line is crisp. On a fake it is rounded or wavy. Pushers should have a short, defined travel with a clean reset. Mushy pushers or a chronograph second hand that stutters and jumps back to zero are common on copies.

Paperwork and packaging

Boxes and cards are easy to print, so never let them carry the decision. Compare the font weight and spacing on the warranty card against known genuine examples, check that the serial on the case matches the card, and look at the booklet binding and paper quality. A perfect box around a bad movement is still a bad watch.

Parameter bands worth checking

• Case diameter: about 41 mm on the modern Portugieser Chronograph. Confirm the exact figure for your reference.
• Case height: roughly 13 mm. A noticeably thicker case usually means a modular movement inside.
• Lug width: 20 mm on most versions of this family.
• Water resistance: 30 m, which means splash resistance only.
• Power reserve: around 46 hours on the in-house caliber. Anything under 40 hours suggests a different base movement.
• Beat rate: 28,800 vibrations per hour, 4 Hz. A stuttering sweep at 6 Hz or 3 Hz is a mismatch.

Pitfalls and red flags

• Grade language such as AAA, 1:1, or super clone. None of it has a defined standard, and it tells you nothing about the movement.
• Photos reused from another listing. Reverse image search them.
• Payment by wire, gift card, or crypto with no buyer protection.
• A seller who refuses a movement photo or an in-person inspection.
• Claims of Swiss manufacture at a price that cannot cover Swiss labor.
• No service history, no return window, and no verifiable identity behind the seller.

Legal and practical risks

Counterfeit watches are infringing goods. Importing them into the United States is illegal, and shipments are subject to seizure and destruction with no refund to the buyer. Selling one onward is a federal offense, so a fake has no resale path. Servicing is the second problem: independent watchmakers generally decline counterfeit work because parts do not exist, and the manufacturer will not touch it. You end up with a watch that costs money to own, cannot be repaired, and cannot be sold.

FAQ

Is IW371743 a real IWC reference?

The IW3717 family corresponds to real Portugieser Chronograph models. Confirm the exact variant, caliber, and dimensions against IWC's own reference data before you compare any watch to it.

Can a fake be indistinguishable from the real thing?

No. Exteriors can get close in photos. Movement finishing, column-wheel construction, and case detail always diverge under inspection.

What should I do if I already bought one?

Stop the payment if the channel allows it, document everything, and report the seller to the platform and to the trademark holder. Do not resell it.

What is a safer alternative?

A preowned genuine watch from a reputable dealer, or a chronograph from a brand at a lower price tier that you can buy new with a warranty.