What people mean by "fake IW371778"
Almost every search for a fake IW371778 comes down to one situation: an IWC Pilot's Watch Chronograph from the 3717 family being sold as genuine when it is not. The 3717 is a 42mm steel chronograph with a day and date at 3 o'clock, a soft-iron inner case, and a chronograph movement built on the Valjoux 7750 architecture. It gets copied a lot because the design is clean, the demand is steady, and the case shape is forgiving to reproduce. The blunt answer: this watch can look convincing at arm's length and still be wrong in four places. The reference string, the movement, the dial printing, and the paper trail.
Start with the reference number
I check the number before I look at anything else. The 3717 line ran through a string of references with different dial and bracelet combinations, and those numbers are documented in IWC's own catalog material and on service invoices. When a listing throws out a number that does not line up with anything in that record, that is a question mark, not a detail. Ask the seller where the number comes from, and ask for a photo of the caseback engraving rather than a stock image. If the answer is vague or the photo is soft, stop there.
Movement: the part that is hardest to fake cheaply
The genuine caliber in a 3717 runs at 28,800 vibrations per hour with 25 jewels and roughly 44 hours of power reserve. Replicas typically use an Asian 7750 clone, a stripped-down automatic, or in the worst cases a quartz module hiding behind a decorated rotor. Three checks catch most of them:
- Push the chronograph start and stop. A real 7750 base feels crisp and resets to zero instantly. Clones often drag or reset a hair off center.
- Look at the subdial layout. Running seconds, a 30-minute counter, and a 12-hour counter should sit where the 3717 puts them, not shifted by a millimeter or two.
- Listen and feel. Rotor wobble, a hollow case ring, or a crown that feels gritty when screwed down are all tells.
If you can get the watch on a timegrapher, rate and amplitude will settle it faster than any photo.
Dial, crystal, and case finishing
Genuine IWC dial printing is razor sharp under a loupe, including the small text under the logo. Replica printing looks fine in a phone photo and muddy at 10x. The sapphire should have a faint blue or purple sheen from the anti-reflective coating on the outside surface, and the inner soft-iron case gives the watch a slightly heavier, denser feel than its size suggests. Check the crown guards, the lug bevels, and the brushing direction on the case flanks. Those are areas where the cheap tooling shows.
Bracelet and clasp
End links should sit flush against the case with no gap you can catch a fingernail in. Look at whether the bracelet uses screws or push pins, and compare that with what the reference should have. On the clasp, engravings should be deep and even, not laser-etched and shallow. A wobbly deployant or a clasp that snaps shut with a tinny click usually means aftermarket, even if the head is real.
Papers, box, and the grey market excuse
Fake warranty cards exist in volume, and a card with no matching serial on the caseback is worth nothing. Sellers who wave off mismatches with a grey market story are worth a second look. Grey market watches are real, but they still come with a serial that matches the case. The same applies to service paperwork: a real service record will list the reference and the serial together.
Price is the loudest signal
A steel 3717 in good condition trades in a fairly narrow band on the secondhand market. If a listing is priced at a fraction of that, the numbers already told you. The reverse trap is a franken watch, real case and dial with a substituted movement or bracelet, priced close to genuine. Compare against several recent sold listings, not asking prices, before you decide anything.
Quick checklist before you pay
- Reference number traces to a documented 3717 variant.
- Caseback serial matches the paperwork.
- Chronograph start, stop, and reset behave cleanly.
- Dial printing is crisp under magnification.
- Bracelet end links sit flush and the clasp engraving is deep.
- Price sits inside the recent sold range for that configuration.
None of these checks takes more than a few minutes. Together they catch the overwhelming majority of fakes, and they also protect you from paying real money for a watch that has been quietly rebuilt.