Answer first
The IW371418 is a reference in the IWC Portugieser Chronograph line. Replicas of this reference are easy to find. Most copies run a 7750-family movement, and that detail matters: the genuine caliber 79350 sits on a 7750 base, so subdial position, pusher feel and beat rate come close to the real watch. A good copy reads as a Portugieser from a step away. Close inspection still finds gaps.
I could not confirm from public sources which dial variant the IW371418 carries. Ask the seller for a photo of the dial and compare it against an IWC catalog image before you pay.
Genuine specs to compare against
- Case: steel, 40.9 mm diameter, 12.3 mm thick
- Lug width: 20 mm
- Crystal: sapphire, domed
- Water resistance: 3 bar (30 m)
- Movement: caliber 79350, automatic, 28,800 vph, 44 h power reserve, 31 jewels
- Dial layout: chronograph minutes at 12, small seconds at 6, date at 3
Measure the case
Use calipers. Replica cases run wide or thick by 0.5 mm to 1 mm in most samples I have seen reported. A 41.9 mm case on a 40.9 mm watch shows at the lugs. Check the lug-to-lug span as well, then check how the strap sits between the lugs. Gaps at the spring bar are a common tell.
Look at the case flanks. The Portugieser case has a flat band and a thin bezel. Copies with a thick bezel or a soft flank edge lose the profile.
Dial and hands
Study four points:
- Numeral edges. Applied numerals should sit flat with sharp corners. Painted numerals on a stepped surface are a downgrade.
- Subdial rings. The snailed rings at 12 and 6 should be crisp and centered. Off-center rings show under a loupe.
- Printing. The text under 12 should be thin and even. Thick print or blurry text is the fastest fail.
- Hands. The feuille hands should taper to a point. Bent tips or heavy lume fill look wrong.
Check the date window at 3. The cut should be square with a clean edge, and the disc should sit close to the dial.
Movement checks
Ask the seller which movement is inside. Answers you will see: A7750, a clone 7750, or a 7750 with a decorated rotor. All three share the 28,800 vph beat rate and the same subdial layout.
Test the chronograph. Start, stop and reset the pushers five times. The reset should snap to zero with no drift on the minute counter at 12. Listen for rotor noise. A loose rotor or a grinding wind is a return.
Crystal, strap and finish
The crystal should be sapphire and slightly domed. Tap it: sapphire sounds dull, mineral glass sounds sharper. Anti-reflective coating on a replica is thin or missing, so expect glare at an angle.
Most copies ship on a leather strap that is not close to the original. Budget for a replacement strap with a 20 mm lug width. Check the buckle engraving depth and the stitching line.
Price bands
Observed asking prices, not fixed values:
- Under $150: printed dial details, mineral glass, rough pushers
- $250 to $450: sapphire, closer dial print, 7750 movement
- $500 and up: decorated movement, better case finishing, sharper hands
Questions for the seller
- Which movement, and is it automatic?
- Case diameter and thickness in millimeters?
- Is the crystal sapphire?
- Can you send a macro photo of the dial text and the date window?
- What is the return policy on movement faults?
What still shows
Case finishing under a loupe, the sound of the rotor, and the strap quality. None of these stop the watch from reading as a Portugieser Chronograph on the wrist. They do show on a desk inspection. Buy from a seller who answers movement questions in writing.