A fake IW371745 is a counterfeit copy of an IWC Portugieser Chronograph, and the tells sit in three places: the dial printing, the caseback engraving, and the movement behind the display back. Real examples show crisp raised text, a signed crown, and a chronograph calibre that matches IWC's published reference data. Copies cut corners on all three.
What gives a fake IW371745 away first?
Start with weight and the dial. A counterfeit case is often plated brass or low-grade steel, so it feels light for its size, and the printing looks flat or fuzzy under a loupe.
- Case weight and how it balances on the wrist
- Dial print quality: real text is sharp, raised, and spaced right
- Subdial spacing and hand length
- Crown and pusher engraving, plus how the pushers feel when pressed
- Caseback text depth and the format of the reference number
- Movement finishing, rotor engraving, and beat rate
How do the dial and hands compare?
IWC finishes dials to a high standard. Text sits with a slight relief, indices are applied and polished, and the subdials are recessed to the same depth.
Subdial layout and position
Chronograph fakes often reuse a generic movement that pushes the subdials out of place. Measure the gap from each subdial to the center and to the case edge. If one sits a fraction off, that points to a donor movement rather than the correct calibre.
Printing and markers
Look at the brand name, the logo, and any text under the 12. Fakes blur the serifs, thin the strokes, or space letters wrong. Applied markers on a fake sit low and catch light in a dull way.
Hands and lume
Real hands are polished on the top surface and matte on the sides. On fakes the two finishes run together, and the lume patch is uneven or the wrong shade.
What should you check on the case?
Case geometry tells you a lot. Genuine cases have crisp edges between brushed and polished surfaces, with no soft transitions or polishing smears.
- Crown: signed with the brand mark, correct size, threads that engage with no grit
- Pushers: firm travel, a clear stop, no wobble
- Lugs: sharp inner edges and even spring bar holes
- Crystal: correct dome or flat profile with anti-reflective coating on both sides
How do you read the caseback and movement?
The caseback is where most fakes fall apart. Engraving should be deep, even, and filled with black lacquer where the design calls for it, not laser-etched with a shallow outline.
Match the reference number to IWC's own data. The brand publishes case size, calibre, and water resistance for each reference, so a mismatch is easy to catch.
Movement checks
A display back makes the job simple. Check the rotor engraving, the finishing on the bridges, and the beat rate. Most modern chronograph calibres run at 28,800 vibrations per hour with a sweeping seconds hand. A stuttering sweep points to a cheap quartz or low-beat movement.
Do serial numbers and papers prove anything?
Papers help, but they do not prove a watch is real. Fake warranty cards, boxes, and manuals are easy to find, and a serial number can be copied from a photo online.
Treat papers as one signal among many. A card that does not match the case number, or a box with the wrong printing, is a warning sign.
What price should raise a flag?
Most steel Portugieser Chronographs sell used for several thousand US dollars. Gold and limited versions run higher. An offer far under the current market range is the single strongest sign that something is wrong.
Check completed sales, not asking prices, before you judge a deal.
Replica or counterfeit: what is the difference for buyers?
A replica is sold as a replica. A counterfeit is sold as the real thing. That line matters, because passing a copy off as genuine is fraud in most markets.
If you buy an IW371745 replica, buy from a seller who states what it is, posts real photos of the actual piece, and names the movement inside. If you pay genuine prices, insist on a return window and a written refund policy.
Quick check before you pay
- Weigh the watch and compare it to a known example.
- Inspect the dial print with a loupe at 10x.
- Press the pushers and feel the reset snap.
- Open the caseback or view the movement through the glass.
- Compare the reference and calibre against IWC's published data.
- Check recent sold prices for the same reference and metal.
FAQ
Can a jeweler tell a fake IW371745 from a real one?
Most watchmakers can, and a brand service center can do it fast. They open the case, check the calibre, and compare the finish to reference photos. Bring the watch, not pictures, if you want a firm answer.
Does a sapphire display back mean the watch is real?
No. Fakes copy display backs all the time. The movement behind the glass is the real test, not the crystal itself.
Is a heavy watch always genuine?
No, but weight still helps. Solid gold and steel cases feel dense for their size, while plated brass and hollow cases feel light. Compare against a known example when you can.
Where can you check IWC reference data?
IWC's own site lists case specs, calibres, and reference photos. Auction archives and large watch marketplaces add sold prices and extra photos for the same reference.