A fake IW371787 is a counterfeit copy of the IWC Portugieser Chronograph reference IW371787, a 40.9 mm automatic chronograph with a chronograph minutes counter at 12 o'clock, small seconds at 6, and a date window at 3. Replicas of this reference range from quartz lookalikes that miss the dial layout entirely to high grade 1:1 copies built on 7750 derived movements. Case measurements, dial layout and the movement visible through the caseback are what separate a convincing copy from an obvious one.
What defines the genuine IW371787?
The Portugieser Chronograph uses a 40.9 mm stainless steel case with 20 mm lugs and a thickness of roughly 12.5 mm. The dial carries applied Arabic numerals, leaf shaped hands, a fine printed minute track and the words Swiss Made at the lower edge.
The reference number identifies the variant, not the model. References in the 3717 family share one case and dial architecture, and the closing digits indicate case metal, dial colour and strap choice.
Modern production runs the IWC 69355 in house column wheel chronograph calibre, a 4 Hz movement with a 46 hour power reserve. Earlier examples of the same family were built on the 79350, a heavily modified Valjoux 7750 base.
How do you spot a fake IW371787?
- Subdial placement. The chronograph minute counter belongs at 12 and small seconds belongs at 6.
- Running seconds. Budget copies often show a 24 hour indicator at 3 where the date should sit, a clear quartz tell.
- Thickness and weight. Quartz fakes feel light and thin, while 7750 based copies often run 14 mm or more.
- Date window. Check the font, the size of the numerals and how the date sits in the aperture.
- Caseback engraving. Reference and serial numbers should be crisp and evenly cut, with matching movement finishing underneath.
- Crystal and hands. Weak anti reflective coating and blunt leaf hands give a copy away under close inspection.
What movement sits inside replica IW371787 watches?
Inexpensive copies use quartz or meca quartz modules. These keep time, but the centre seconds hand ticks rather than sweeps, and the extra subdial usually reads 24 hours instead of holding a date.
Mid and upper tier replicas use the A7750, a Chinese made version of the Valjoux 7750. That architecture drives the running seconds at 9, so builders either accept the wrong layout or fit a modified dial and extra gearing to push the hands to 12 and 6.
No replica carries the IWC 69355. The closest copies decorate a 7750 derived rotor and plates to imitate the look of the in house calibre.
What should you check before buying a replica IW371787?
- Request macro photos of the dial and the caseback from the seller.
- Confirm the subdials sit at 12 and 6 and the date window sits at 3.
- Ask for the measured case diameter, lug width and thickness.
- Check date alignment, dial printing and hand finishing in the photos.
- Ask for a running video or timegrapher reading to confirm the movement works through all chronograph functions.
- Confirm strap, clasp or buckle markings and the water resistance claim before paying.
Is a 1:1 replica IW371787 identical to the original?
No. A strong copy matches the diameter, thickness, dial layout and external markings closely enough to pass at arm's length. The movement is never the in house calibre used by IWC, and the finishing under the display back shows the difference.
How much does a replica IW371787 cost?
Pricing runs in tiers. Quartz versions sit at the bottom, A7750 based watches occupy the middle, and high grade copies with better cases and dials sit at the top of the range.
Price alone is not a quality signal. A seller charging high grade money for a quartz movement is the most common way buyers lose money on this reference.
Can a watchmaker tell a fake IW371787 instantly?
Yes. Opening the caseback exposes the movement, rotor engraving and finishing within seconds. Even without opening the watch, a watchmaker catches wrong subdial spacing, an incorrect date font or a thickness that sits outside spec.
Original versus replica at a glance
- Movement: IWC 69355 or 79350 in the original, quartz or A7750 in a fake.
- Subdials: minute counter at 12 and small seconds at 6 on both, if the copy is built correctly.
- Caseback: display back showing a finished in house calibre versus a decorated clone.
- Weight and feel: solid steel heft versus a lighter or thicker case on most copies.