The short answer
A "fake IW371491" is a counterfeit of IWC's Portugieser Chronograph, and the practical question is not where to buy one but how to recognise one. Fakes of this reference are common because the design looks simple from a distance: two subdials, applied numerals, feuille hands, a stainless steel case around 40.9 mm. The differences live in details that product photos conceal, which is why authentication matters far more than a seller's photo set. The sections below cover what the genuine reference actually is, which details separate it from replicas, and what to verify before any money changes hands. Buying a counterfeit is not a harmless shortcut: importing or selling counterfeit trademarked goods is prohibited in the United States, replicas come with no warranty or service path, and a counterfeit can never be resold as the genuine article.
What the IW371491 actually is
The reference sits in the Portugieser Chronograph family, IWC's classic two counter chronograph in stainless steel. The IW3714 generation kept a consistent architecture: a 40.9 mm case roughly 12 to 13 mm thick, running seconds at 6 o'clock, a 30 minute chronograph totaliser at 12 o'clock, no date window, a closed and engraved caseback, and sapphire crystal with antireflective coating. Earlier pieces in the family run the 79350 calibre, a 28,800 vph movement based on the Valjoux 7750 with a power reserve in the mid 40 hour range. Later Portugieser Chronographs moved to the in-house 69355. Dial colours, numeral finishes and strap options changed by reference, so confirm the exact dial, hand finish and strap for this reference against IWC's own reference data instead of trusting a listing title or a marketplace photo.
Tells that separate genuine from replica
Dial, printing and hands
Genuine dial printing is sharp and evenly weighted, with consistent stroke width in the brand name and the city line. Replicas typically show text that is slightly heavier, blurred at the edges, or misaligned against the minute track. The applied numerals on a genuine piece sit flat and flush, with crisp polished edges and no visible adhesive residue. Feuille hands are thin, evenly tapered and mirror polished along the whole length; counterfeit hands often look thicker near the base or show a duller, brushed finish. Subdial rings should be perfectly circular with even spacing and no gap where the ring meets the dial surface.
Case, crown and caseback
Check lug shape and profile, not just diameter. Genuine lugs taper cleanly and the case flanks show sharp, consistent brushing with polished bevels that meet at a defined line. The crown is signed and the engraving is deep and centred, not shallow or off axis. On a closed caseback, reference and serial engravings are crisp, correctly spaced and consistent in depth. Replicas commonly show shallower engraving, a slightly different font weight, or a caseback that sits proud of the case band.
Movement and behaviour
A chronograph with running seconds at 6 o'clock is a layout counterfeiters struggle to execute cleanly. Reset behaviour is a good test: genuine chronograph hands snap back to zero instantly and hold position, while cheaper movements drift or bounce. Winding feel, pusher travel and the sound of the rotor should feel dense and mechanical. Where a display back is present, finishing, engraving and rotor decoration are the fastest tells of all.
Parameter bands worth checking
- Case diameter: 40.9 mm nominal; anything notably smaller or larger is a different reference or a fake
- Case thickness: roughly 12 to 13 mm depending on generation
- Water resistance: rated at 3 bar, so treat it as splash resistant only
- Beat rate: 28,800 vph on the 79350 family
- Power reserve: mid 40 hour range, not days
- Layout: two counters, running seconds at 6, chronograph minutes at 12, no date
Pitfalls when buying
- Buying from a marketplace listing with stock photos and no serial images. Ask for photos of the actual caseback, crown and clasp.
- Treating box and papers as proof. Packaging is the easiest element to counterfeit; a service record from an authorised workshop carries more weight.
- Assuming a low price means a bargain. Deep discounts on a steel chronograph usually mean a counterfeit, a stolen watch, or a rebuilt movement.
- Skipping a movement service check on older pieces. A worn 7750 base chronograph can cost more to restore than the discount it came with.
- Overlooking import and customs rules. Counterfeit goods seized at the border are destroyed and the buyer loses the money.
FAQ
How can I tell if an IW371491 is genuine before paying?
Compare the case, dial printing and engraving against IWC reference data, then have a watchmaker inspect the movement. For anything expensive, a paid authentication from a specialist is cheap insurance.
Is buying a replica IW371491 legal?
No. Importing counterfeit trademarked goods into the United States is prohibited, and selling them is a criminal offence. Buyers also give up warranty, parts availability and any resale value.
Do all genuine examples come with box and papers?
No. Many were bought without keeping the packaging. Absence of papers is normal on older pieces, but it should lower the price and increase the case for independent authentication.
Does the reference use an in-house movement?
Earlier Portugieser Chronographs use the 79350, based on the Valjoux 7750. Later generations use the in-house 69355. Confirm which applies to the exact piece you are considering.