A fake IW371408 usually reveals itself in three places: the chronograph movement, the position of the two subdials, and the engraving on the caseback. Because the IW3714 family has been copied for many years, no single detail proves authenticity on its own. You need to check several features together, and the movement check matters most.
What the IW371408 actually is
The IW371408 belongs to the IWC Portugieser Chronograph family, known by collectors as the IW3714 line. References in this family share a slim bezel, applied numerals, leaf hands, and two subdials: a 30 minute counter at 12 o'clock and small seconds at 6 o'clock. The last two digits of the reference mark the dial and case combination, so one authentic reference has one specific dial finish, one set of hands, and one factory strap option. Replica sellers often mix parts from different variants, and that mismatch is the first thing worth checking.
The movement is the hardest part to copy well
This generation of the Portugieser Chronograph is built on a modified Valjoux 7750 base, known in house as calibre 79350. An authentic example winds smoothly, starts and resets the chronograph with a clean snap, and keeps the small seconds hand sweeping without stutter. Details to inspect:
- Rotor engraving: text and logo should be crisp, evenly spaced, and correctly spelled.
- Chronograph feel: pushers should engage with light pressure and reset straight to zero.
- Rotor noise: a loose, rattling weight is a warning sign on any watch at this price.
- Movement finish: perlage, striping, and blued screws should look clean rather than painted or printed.
Dial, hands, and subdial spacing
On a genuine dial the printing sits flat, the subdial rings are sharp, and everything is symmetric on a vertical axis. Look for these tells:
- Subdial alignment: the top and bottom counters should sit on one clean line through the center.
- Print quality: the brand name and city line should stay sharp under magnification, with no bleed or blur.
- Applied numerals: polished, raised, and set evenly, with no visible adhesive at the base.
- Hands: leaf hands taper to a thin tip with a clean bevel along both edges.
- Date window: the classic IW3714 layout has no date, so a date aperture on a dial that should not have one is a strong flag.
Caseback, reference, and engraving
Depending on the variant, the back is either a solid engraved cover or a sapphire display. In both cases the reference number, the case number, and the brand engraving should be cut into the metal, not lasered on top of it. Edges of the engraving look sharp and slightly recessed on a real watch. On copies the text is often too shallow, too large, or positioned off center. Ask for a straight-on photo of the back with the strap moved aside, since this is the shot most sellers avoid.
Where replicas usually slip
High end copies get the case shape and dial color close. They struggle with the crown action, the thickness of the case, the polish on the bezel edge, and the way the strap meets the lugs. A case that measures noticeably thicker than the original, a crown that grinds when set, or lugs that show a gap against the strap are all reasons to walk away.
A practical buying checklist
- Confirm the reference number matches the exact dial and case finish shown in the listing.
- Request a clear photo of the movement and the caseback engraving.
- Ask for a short video of the chronograph starting, running, and resetting.
- Compare case proportions and subdial placement against reference photos of the same variant.
- Check the paperwork, box, and service history against the serial on the case.
- Buy from a seller who accepts a return after independent inspection.
If a price sits far below the market for the reference and the seller resists detailed photos, treat the watch as a fake IW371408 until proven otherwise.