The short answer: a fake IW371485 is not one watch. It is a family of counterfeit IWC Portugieser Chronograph pieces built to three rough quality tiers, and the tier you want depends on four criteria. Those criteria are subdial layout (the genuine chronograph layout stacks the 30-minute counter at 12 and running seconds at 6), movement architecture and its tells, case and dial finishing, and whether an exhibition caseback exposes the movement to inspection. For daily wear, the top pick is the 7750-derived automatic chronograph tier with a sapphire crystal, an engraved rotor and a working chronograph. The Asian automatic tier and the quartz tier sit below it, each with tradeoffs worth knowing before you pay.

What the IW371485 reference covers

IWC's Portugieser Chronograph sits inside the IW3714xx reference block, and that block has run through many dial colors, case metals and limited edition runs over the years. That history matters when you judge a watch. Two genuine examples from different production years can differ in hands, printing and caseback engraving, so a single photo comparison will not settle the question. Confirm the specification against IWC's own reference data for the exact variant first, then compare finishing and function.

What counterfeits get wrong most often

  • Subdial positions that do not match the reference. Many mid-tier chronographs put the counters at 3 and 9 instead of 12 and 6, or carry a decorative 24-hour dial where a real totalizer should be.
  • Chronograph feel. Pushers on a real chronograph have a defined start, stop and reset sequence. Cheap builds feel mushy or reset while the movement is still running.
  • Finishing transitions. Brushed flanks against polished bevels, crisp lug edges and even graining are the first details to slip on a copy.
  • Crystal and dial. Mineral glass instead of sapphire, milky anti-reflective treatment, soft index printing and lume that fades in minutes.
  • Movement visibility. Under an open caseback, look for a generic rotor, wrong engraving, painted rather than heat-blued screws, and a seconds hand that ticks in steps instead of sweeping.

Tier 1: 7750-based automatic chronograph (top pick)

The Valjoux 7750 family and its clones drive most credible chronograph replicas, and several IWC chronograph calibres share that architecture. This tier gives a running seconds subdial, a working 30-minute counter, a date function and a smooth sweep.

  • Pros: correct chronograph function, closest case weight and thickness, sapphire crystal commonly fitted, serviceable by independent watchmakers.
  • Cons: rotor noise on cheap batches, higher cost than lower tiers, thickness can still run a millimeter or two off the genuine case.
  • Best for: buyers who actually wear the watch and want the chronograph to work.

Tier 2: Asian automatic chronograph

This tier uses cloned or modular automatic movements, usually with lighter case finishing and a lower grade crystal.

  • Pros: automatic winding, lower cost than Tier 1, decent look on a wrist at arm's length.
  • Cons: subdial placement often wrong, weak chronograph module, no parts support, timekeeping that drifts.
  • Best for: casual wearers who rarely touch the pushers.

Tier 3: Quartz

  • Pros: cheap, accurate timekeeping, no service costs.
  • Cons: ticking seconds hand, subdials that do nothing or track 24 hours, light case that feels wrong in the hand.
  • Best for: costume use only. Nobody who handles watches will mistake it for the real reference.

Tier 4: genuine pre-owned or a different reference

  • Pros: passes inspection, serviceable, warranty history, resale value.
  • Cons: real money, limited availability, a service bill on older examples.
  • Best for: anyone who needs the watch to stand up to a dealer or collector.

Five checks that settle most cases

  1. Run the chronograph: start it, let 60 seconds pass, stop it, reset it, then see where the minute counter lands.
  2. Measure the case diameter and thickness against the published spec for that reference.
  3. Read the caseback: rotor engraving, jewel count, screw finish, winding direction.
  4. Angle the crystal toward a light source. Sapphire throws sharper reflections than mineral glass.
  5. Study the dial print under magnification for crisp edges, correct font weight and clean spacing.

Legal and practical notes

Counterfeit watches infringe trademarks and can be seized at the border. They arrive with no warranty, no parts network and no service support, so a repair often costs more than the watch. A replica is also not a genuine IWC, and selling or presenting one as genuine is fraud. Buy with that in mind and keep the purchase as personal use.

Recommendation

If you want one piece that looks right on the wrist and keeps working, the 7750-derived automatic tier is the pick. Step down to the Asian automatic tier only if the chronograph will stay untouched and the budget is tight. Skip quartz if the dial layout matters to you at all. And if the goal is a watch that survives inspection, save for a genuine example instead of chasing a copy.