The short answer
If someone offers you an IW371618 for a few hundred dollars, it is a replica. There is no bargain here, only a copy. Genuine Portugieser Chronographs in stainless steel sell for roughly $8,000 and up, and most of that money sits in the movement. A fake can reproduce the dial layout from across a table. It cannot reproduce the 13 mm case profile, the hand finishing, or an in-house column wheel chronograph. The reference number is the easiest thing in the world to print on a caseback. Everything else is hard.
What the IW371618 actually is
The reference belongs to the 3716 family, the current 41 mm Portugieser Chronograph that replaced the older 3714 generation in 2020. The big change was the movement: IWC dropped the modified Valjoux 7750 and moved to its own calibre 69355, an automatic column wheel chronograph with about 46 hours of power reserve. Family traits worth memorizing:
- 41 mm case, roughly 13 mm thick, thin bezel, wide dial opening
- Two subdials stacked vertically at 12 and 6, no date window
- Leaf shaped hands and a clean, uncluttered layout
- Sapphire front and back, so the movement is on display
- 60 m water resistance, alligator strap, signed deployant clasp
Before you compare anything, pull up IWC's own listing for the exact reference and note the dial color and case metal. A surprising share of online fake spotting arguments come from people comparing two different references.
Where replicas give themselves away
- Thickness. Copies built on a 7750 pattern usually land around 14.5 to 15 mm and sit noticeably tall. Put it beside a real one and the slab sided look is obvious.
- Subdial spacing. The two counters should sit tight against the vertical axis. Fakes often push them apart or fit clumsy metal rings around them.
- Printing. Look at the letter spacing in the logo and in the town name under it. Genuine dial printing is razor sharp under a loupe. Copies go soft at the edges.
- Hands. The leaf hands should be crisp, evenly polished or blued, with a clean center. Bent tips and dull reflections are a warning.
- Pushers and crown. Genuine chronograph pushers have a short, defined travel. Mushy or gritty pushers usually mean a cheap module.
- Caseback engraving. Reference and serial should be cut cleanly and match the paperwork. Shallow, blurry or misaligned engraving is a bad sign.
Movement check
Flip it over. The 69355 is nicely finished, with stripes, perlage and a signed rotor, and the chronograph should start and stop with a light, positive click. A decorated 7750 or a hand wound Chinese chronograph with a fake rotor plate will feel different the moment you press the top pusher. If a seller will not let you work the chronograph, that is your answer.
Paperwork, serials and price
Serials should match across the caseback and the guarantee card, and IWC extends its international warranty when the watch is registered in My IWC. A seller who refuses to register, or who cannot produce a card that ties to the serial, is telling you something. Price is the fastest filter of all. A steel Portugieser Chronograph at $2,000 is not a deal, it is a replica with a hopeful price tag.
Quick checklist before you pay
- Measure the thickness. Over 14 mm, walk.
- Loupe the printing and the logo letter spacing.
- Run the chronograph and feel the pushers.
- Match serial to card, then try the My IWC registration.
- Compare the asking price to retail. If it is a fifth of retail, it is not a real watch.