A fake IW371643 is a counterfeit or replica of the IWC Portugieser Chronograph, a 41 mm steel watch with a 30-minute counter at 12 o'clock, small seconds at 6, and a date at 3. The fastest tell is the movement: genuine watches run IWC calibre 69355 with a column wheel, while most fakes hide a Valjoux 7750 derivative or an Asian clone. Every other difference, from dial printing to lug bevels, follows from that gap in machining budget.
What Is the IW371643?
The IW371643 sits in the 3716 series, the 41 mm generation of the IWC Portugieser Chronograph. It uses a stainless steel case, sapphire crystal with anti-reflective coating on both faces, and a sapphire display back. Dial colors and strap options shift between production years, but the case dimensions and calibre family do not, so IWC's own reference data is the baseline for any comparison.
How Do You Spot a Fake IW371643 Fast?
Start at the dial, then work outward to the case, then finish at the movement.
- Dial printing: authentic IWC and SCHAFFHAUSEN lettering is crisp with even tracking, while fakes show fuzzy edges and thick serifs.
- Subdials: the 30-minute counter sits at 12 and small seconds at 6, with sharp rings sunk below the main dial plane.
- Date window: a real aperture is cleanly cut with a fine bevel and a date wheel centered in the frame.
- Hands: leaf-shaped hands are polished on top and matte on the flanks, while fakes usually carry one flat finish.
- Caseback: genuine engraving is deep and sharp, and the reference stamp matches the dial variant.
Why Does the Movement Expose Most Fakes?
Calibre 69355 is the hardest part of this watch to copy at a low price point. It is an automatic column-wheel chronograph with pawl winding, a 46-hour power reserve, and a 4 Hz beat rate. Press the top pusher slowly: a column wheel engages with a light, defined click, while a cam-actuated clone stutters and feels spongy.
Decoration tells the rest of the story. Genuine bridges carry Geneva stripes, blued screws, and clean bevels, while budget clones show coarse graining and stamped lettering on the rotor.
Is the Caseback a Reliable Check?
The 3716 generation uses a see-through caseback, so the movement, rotor, and rim engraving stay visible. Replica casebacks often show shallow laser etching, the wrong font weight, or a missing reference number. If a watch sold as an IW371643 has a solid steel back, treat it as a warning rather than a rare variant.
What Separates Cheap Replicas From High-End Ones?
- Case finishing: better builds polish and brush the lugs in separate steps, cheaper ones blur the transition.
- Crystal: sapphire with double-sided AR coating on top tiers, mineral glass or single-sided coating on budget tiers.
- Dial hardware: applied indices with polished edges instead of printed or poorly glued markers.
- Movement: decorated clones with engraved bridges instead of undecorated generic calibres.
- Strap: alligator-grain leather with a signed pin or deployant buckle instead of stiff synthetic leather.
Frequently Asked Questions
Can a fake IW371643 pass a jeweler's inspection?
A watchmaker who opens the back identifies a fake in minutes through movement architecture, finishing, and engraving quality. Externally, only the best replicas hold up under a loupe for more than a few seconds.
Why do fake IW371643 listings use the exact reference number?
Sellers copy reference numbers because buyers search with them. The number alone proves nothing, since it is stamped or laser-engraved on the caseback of both genuine and fake watches and can be lifted from any online photo.
How much should a genuine IW371643 cost?
Authentic steel Portugieser Chronographs trade for several thousand dollars on the secondary market, with full sets of box and papers at the top of that range. A price far below market is the single most reliable sign of a counterfeit.