A real IWC IW371704 is a 42 mm Portuguese Chronograph Classic with the in-house caliber 89361 flyback chronograph, a combined hour and minute counter at 12 o'clock, small seconds at 6 o'clock, and a date at 3 o'clock. Most fakes fail on one of those points: the running seconds sit at 9 o'clock, the counter at 12 has only one hand, the flyback does not work, or the case is too thick. Use the checks below before you buy.
What is the fastest way to spot a fake IW371704?
Look at the subdials first. A real IW371704 has a combined hour and minute counter at 12 and small seconds at 6. If the watch has running seconds at 9 o'clock, it uses a standard Valjoux-style chronograph layout and is not an IW371704.
Next, test the flyback. Start the chronograph, let it run, then press the lower pusher once. A real caliber 89361 resets to zero and restarts in one press. A fake usually stops, resets, or does nothing until you stop it first.
Best Fake IWC IW371704: 1:1 Pilot's Chronograph Buyer's Guide
Does the real IW371704 have a flyback movement?
Yes. The IW371704 uses IWC caliber 89361, an in-house automatic flyback chronograph. The movement drives the combined counter at 12 with two hands, one for hours and one for minutes. That layout is the single most useful authenticity check because it is expensive to copy.
Ask for a short video that shows the chronograph starting, running, and performing a flyback reset. A still photo cannot prove the movement works as designed.
How does case size expose a replica?
The real case measures 42 mm across and about 14.5 mm thick. Replicas often run 1 mm to 2 mm thicker because the copied movement and module need more space. A thicker case changes the side profile and makes the watch sit high on the wrist.
Check the lugs, crown, and pushers under macro light. Real IWC finishing is crisp, with sharp bevels and clean transitions. Fakes show soft edges, uneven brushing, and a crown that feels loose or gritty.
Which dial details matter most?
- Printing: The IWC logo and Schaffhausen text are thin, sharp, and evenly spaced. Replica print looks bold, fuzzy, or slightly raised under a loupe.
- Subdials: Real subdials have fine concentric finishing and clean inner edges. Fakes often use flat or shallow subdials.
- Hands: Gold-plated hands reach the correct tracks and have a clean curve. Fake hands can be too flat, too yellow, or too short.
- Date: The date sits at 3 o'clock with a correct font and clean aperture. Crooked or oversized date numbers are a warning sign.
What should the caseback show?
A real IW371704 has a sapphire display back with crisp engravings. The reference number, serial number, steel marking, and water resistance text should be sharp and consistent with the papers. Blurry laser engraving and mismatched serials are common on replicas.
Look at the movement finishing through the back. Real IWC finishing includes clean Geneva stripes, polished screws, and a signed rotor. A fake may look busy but shows rough edges, wrong screws, or a generic rotor.
Can paperwork and price prove authenticity?
No. Replica sellers copy boxes, booklets, and warranty cards, so papers alone do not prove a watch is real. Price is a better warning: a genuine IW371704 does not sell for a few hundred dollars. A deal far below the pre-owned market deserves a professional inspection.
Buy from a seller with a clear return policy and ask for macro photos of the dial, caseback, and movement. For a high-value purchase, a watchmaker should open the case and verify the movement and serial.
What is the safest final check?
Have an IWC-trained watchmaker or authorized dealer authenticate the watch. They can confirm the caliber 89361, the flyback function, the case dimensions, and the serial. That step costs far less than a fake at a real watch price.