Answer first: a "fake IW371647" is a counterfeit copy of the IWC Portugieser Chronograph from the 3716 reference family, and the top pick for anyone who wants this watch is a genuine pre-owned IW371647. It is the only version that keeps resale value, survives a watchmaker's inspection, and can still be serviced years from now. The criteria that settle the question are movement architecture, dial and subdial layout, case finishing, and the legal and resale consequences of owning counterfeit goods.

What the IW371647 Reference Is

The Portugieser Chronograph is a two-register chronograph in a slim steel case, with applied Arabic numerals, leaf-shaped hands, a fine minute track, and a chronograph counter paired with running seconds. IWC has built the 3716 line across more than one generation, and the movement inside changed between them, so the same reference number can appear with different internals depending on the production year. Before you judge a watch, genuine or not, check the exact specification against the manufacturer's own reference data instead of a marketplace listing.

People search for a fake IW371647 for three reasons: they are checking a second-hand offer they do not trust, they want to know how close a replica gets, or they are shopping the replica market head-on. The inspection points below apply to all three.

Criterion One: Movement and Function

The movement is the hardest part to copy and the easiest place to catch a counterfeit. Over the life of this line IWC has used both a chronograph caliber derived from a mass-produced Swiss base and, in later production, in-house movements from its 69000 family. Copies typically hide a generic Asian chronograph movement behind an engraved rotor plate.

Pros (points that support a genuine watch)

  • The chronograph starts and stops with crisp, even pusher resistance on both pushers.
  • Reset snaps the counter hand back to zero in one clean motion, with no overshoot.
  • The rotor winds with a soft, continuous sound rather than a loose rattle.
  • A watchmaker can identify the caliber on sight and order parts for it.
  • The movement number and case number match the paperwork and the caseback.

Cons (points that suggest a copy)

  • Mushy or grinding pushers, or a chronograph hand that stops slightly off zero.
  • A bridge plate screwed over a movement that does not match the reference layout.
  • Caseback text that is stamped or laser-etched shallow, rather than engraved.
  • No service history and no way for a watchmaker to source components.

Best for: any buyer spending real money. If the movement cannot be identified by a professional, walk away.

Criterion Two: Dial, Subdials, and Case Finishing

Subdial spacing follows the movement underneath. A copy built on a different engine often shows counters that sit noticeably wider or tighter than the reference, and that offset is visible in a photo at arm's length. Printing, applied numerals, and case transitions are the second layer of evidence.

Pros (signs of a correct watch)

  • Printing is crisp under a loupe, with no bleed, doubling, or uneven stroke weight.
  • Numerals are applied with polished bevels, not glued flat to the dial.
  • Brushed and polished case surfaces meet at sharp, defined lines.
  • Sapphire crystal shows anti-reflective treatment, and the crown is correctly sized and signed.
  • Lug shape, thickness, and taper match the reference photos you can verify.

Cons (signs of a copy)

  • Thick or fuzzy text, wobbly minute track, or a logo that sits too low or too high.
  • Flat numerals, mineral glass, or coating applied to the outside of the crystal only.
  • Soft case edges, an over-polished caseback, or lugs that look slightly wrong in profile.
  • A date aperture that sits where the reference manual does not show one, which is a common tell on cheaper builds.

Best for: buyers comparing two watches side by side. Photograph the dial straight on and compare it to verified reference images before you decide.

Option One: Genuine Pre-Owned IW371647

  • Pros: holds resale value, is fully serviceable, passes any inspection, comes with a legal title, and a full set of box and papers adds to the price you can recover later.
  • Cons: the highest upfront cost, condition varies between examples, and you need a trusted dealer or an authentication service before you pay.

Best for: anyone who wants the watch rather than the look, and who may sell it later.

Option Two: Top-Tier Replica Build

  • Pros: the closest visual match available, often with a cloned movement layout so the counters sit in the right place, and better case finishing than cheaper tiers.
  • Cons: still a counterfeit, which means customs seizure and legal exposure in the United States and many other countries, no resale value, no parts supply, and it will not survive a watchmaker's bench inspection.

Best for: buyers who accept the legal and practical risk and never intend to resell or present it as genuine. Understand that the price of these builds is not trivial.

Option Three: Budget Replica

  • Pros: low cost and easy to replace if it fails.
  • Cons: the visible tells are obvious, including off subdial spacing, weak printing, mineral glass, and a movement that often stops within a year.

Best for: nobody trying to pass a watch off as the real thing. As a curiosity it has some value; as a watch it does not.

Option Four: An Honest Steel Chronograph

  • Pros: legal to buy and import, backed by a real service network, holds some resale value, and you can wear it without checking who is looking at your wrist.
  • Cons: it is not the reference you wanted, and the small design details will differ.

Best for: buyers who want the two-register chronograph look and care more about ownership than about the logo.

Quick Checklist Before You Buy Anything

  1. Confirm the reference specification against the manufacturer's data, not a listing.
  2. Ask for movement photos, a caseback photo, and a straight-on dial photo.
  3. Have a watchmaker open the case before money changes hands.
  4. Match the movement number to the paperwork.
  5. Price the watch against current secondary-market listings so a bargain does not blind you.
  6. Remember that importing counterfeit goods can mean seizure and loss of what you paid.