If you are shopping for a fake IW371429, the top pick is a 41 mm twin-counter build with a working chronograph, a display caseback finished to match the reference, and a dial that keeps the subdial layout of the genuine watch. The four criteria that matter are movement type, dial architecture, case and bracelet finishing, and how open the seller is about what sits inside the case. Get those right and the watch reads as a plausible Portugieser Chronograph on the wrist. Get them wrong and no amount of polished steel will hide it.

What the IW371429 Reference Actually Is

The IW371429 sits inside IWC's Portugieser Chronograph family, a line built around a clean twin-counter dial, slim lugs and a strap-first design rather than a bracelet-first one. Because IWC has shipped this family with several dial colours, case metals and movements over the years, your first job is to pull the official listing for the exact number and save the reference photos. Compare those images against the copy, not against a random photo from a forum thread. A copy can be well made and still be wrong for the reference you asked for.

Criterion 1: The Movement Decides the Watch

The movement is the one part a buyer can verify without opening the case, because it dictates the dial. Older Portugieser Chronograph builds rely on a modified Valjoux 7750 base, while later ones use IWC's in-house chronograph calibre. Those two approaches place the counters and the date differently and produce different case thickness.

  • Pros of a 7750-based copy: wide parts availability, easy service by any competent watchmaker, lower price, familiar pusher feel.
  • Cons of a 7750-based copy: thicker case, rotor wobble when you shake it, subdial spacing that can drift from the reference.
  • Pros of a column wheel or in-house style copy: closer pusher feel, thinner profile, better looking display caseback.
  • Cons: higher cost, harder to repair locally, more variation between batches.

Use case: buy the 7750-based build if this is a daily wearer you want serviced cheaply. Buy the in-house style build if the caseback is the part you care about and you accept the servicing hassle.

Criterion 2: Dial Architecture and Printing

The dial is where most fakes fall apart under a loupe. Check that the two counters sit where the reference puts them, that the rings are recessed rather than printed flat, and that the numerals and the minute track are sharp at the edges. Genuine dial printing is crisp with no ink bleed into the surrounding surface. On a weak copy the printing looks slightly soft and the subdial rings sit flush. Also compare the hand shapes: leaf hands on a Portugieser should be polished on the flat and matte on the bevel, and the tips should reach the track without overrunning it.

Criterion 3: Case, Crystal and Finishing

  • Good signs: brushed flanks with polished bevels that meet in a clean line, pushers that sit level with the case band, sapphire with a faint blue or purple tint at an angle, lug holes drilled straight.
  • Bad signs: fuzzy transitions between brushed and polished surfaces, an oversized crown, mineral glass that shows no anti reflective tint, caseback engraving that is stamped rather than cut.

Use case: if you wear the watch with short sleeves and people see the case sides, spend your budget on case finishing before you spend it on a decorated rotor.

Criterion 4: Seller Transparency

A seller who will tell you the movement family, the case dimensions in millimetres, the crystal material and the strap leather type is almost always selling a better watch than one who answers with photos only. Ask for a timed video of the chronograph running, start, stop and reset. Ask what happens if the watch arrives with a stuck pusher. Vague answers are the cheapest red flag you will ever get.

Quick Verdict

For most buyers the sensible pick is a mid tier first copy with a working 7750-based chronograph, a correctly spaced dial and a clean case profile. Skip the cheapest tier, which usually trades a working chronograph for a decorative one, and skip the top tier unless you specifically want the display caseback and the finer pusher action. Match the dial to the exact reference photos before you pay, and treat the strap as disposable.