The Short Answer

Buy a fake IW371424 on dial accuracy first and movement second. The Portugieser Chronograph is a clean, symmetric face with two counters, which means every flaw is visible at arm's length. A replica with a correct 40.9 mm case, a midcase around 12.5 mm thick, properly placed subdials at 12 and 6, and crisp applied numerals will survive casual inspection. A replica with a 42 mm case and a 14 mm slab profile will not, no matter how good the listing photos look. Ask the seller for a video, not stills. Have them start the chronograph, let it run for a minute, and reset it while the camera is on the dial.

What to Check Before You Pay

  • Dial layout. Two counters only: chronograph minutes at 12 and running seconds at 6. Extra subdials, a 24-hour indicator, or a date window placed anywhere other than 3 o'clock signal a generic movement squeezed into the case.
  • Printing weight. Genuine dial text is thin and sharp. Replica printing often looks heavy or slightly fuzzy at the edges when you zoom in. Compare the space between the brand name, the model text, and the 12 index.
  • Numerals and hands. The applied numerals should sit flat and reflect light evenly. The feuille hands should have a clean taper with no burrs, and the leaf shape should not look stamped and flat.
  • Case profile. Polished bezel, brushed flanks on some versions, and a lug shape that curves down toward the wrist instead of sitting straight. Look at the transition between the bezel and the case band. A hard, unbroken line means a cheap casting.
  • Caseback. If the reference uses a sapphire display back, the movement should look finished, not like a bare plate with a sticker rotor. Rotor engraving should be consistent in depth and font.
  • Strap or bracelet. Stitching should be even and the leather should have a grain. A plastic-smelling strap is a sign the rest of the watch was built to the same standard.

Parameter Bands That Hold Up

  • Case diameter: 40.5 mm to 41.5 mm. Outside that range, the dial proportions start to look wrong.
  • Thickness: 12.5 mm to 13.5 mm. Anything at 14 mm or more usually points to a thick base movement with a module on top.
  • Weight: roughly 85 g to 110 g on a leather strap. A watch that feels hollow or top-heavy is a warning sign.
  • Movement type: self-winding. Depending on the reference year, the genuine movement is either a heavily modified Valjoux 7750 base or an in-house chronograph calibre, so a hand-wound movement visible through the back is an immediate mismatch.
  • Chronograph feel: the start pusher should engage with a firm, short travel. Gritty or mushy pushers mean the levers are rough and the watch will not hold up to regular use.
  • Water resistance: treat any claim beyond splash resistance as marketing. Do not swim with it.

Pitfalls

  • Recycled photos. Reverse image search the listing pictures. If the same shots appear under three sellers, you are looking at a stock listing, not the actual watch.
  • "Swiss movement" with no proof. Ask for a clear caseback video. If the seller stalls, walk away.
  • Date alignment. A date that sits high or low in its window, or a font that is too bold, is one of the easiest tells on the wrist.
  • Snap-back casebacks. A screw-down back that turns out to be a snap fit does not seal and will let moisture in.
  • Counterfeit chronograph function. Some low-end replicas hide a dummy subdial that never moves. Always confirm the minute counter advances.
  • Box and papers upcharges. Packaging does not improve the watch. Put that money into a better movement instead.

FAQ

How close is a good fake IW371424 to the genuine watch? On the wrist, a well-built replica can look convincing from a few feet away. Up close, the differences show in printing sharpness, hand finishing, and the movement finish seen through the display back.

Which movement should I ask for? An automatic chronograph movement with a working minute counter and a smooth sweep. Ask the seller to name the base calibre and show it running.

How do I verify functions remotely? Request one continuous video showing the watch from the dial, then the caseback, then the chronograph starting, running past the one-minute mark, and resetting to zero.

Is a bracelet version harder to fake? Yes. Bracelet end links and clasp engravings are difficult to replicate, so a leather strap version usually hides more flaws.