First, know which Portugieser you're copying
The IW371717 sits in IWC's Portugieser chronograph family, the two-register watch with leaf hands, applied numerals and that thin railway minute track around the edge. The family has run since the late 1990s, and the older versions used a Valjoux 7750-based calibre while the current one runs IWC's in-house 69355. That matters when you buy a replica, because the tells are different on each generation. If you buy the wrong case, the wrong subdial spacing or the wrong caseback, the watch reads as fake from across a table. Get those three right and almost nobody looks closer.
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My pick: the 41mm two-register on a modified A7750
If I were buying one today, I'd take the 41mm steel case with a silver-plated dial, gold-tone applied numerals and leaf hands, running a modified Asian 7750. It is the closest thing to the reference in proportion and it is the version most sellers actually stock, so you have room to reject a bad sample and ask for another. The movement is the whole game here. A stock 7750 puts a running-seconds subdial at 9 o'clock, and the Portugieser has nothing there. Good replicas move the running seconds to 6 and drive the chronograph minutes at 12. If you see a subdial at 9, walk away, no matter how nice the dial photo looks.
Fake IW371717 Question: How to Check an IWC Portugieser
- Subdials at 12 and 6 only, nothing at 9
- Case thickness around 13 to 14mm. The 7750 base is tall, and cheap builds hit 15mm and sit like a puck
- Applied numerals with clean edges, not printed flats
- Railway minute track that stays sharp under a loupe, since that is the first thing to blur on a cheap dial print
- Caseback style matching the generation you're copying, not a generic display back on every version
Option two: the smaller 3714-style case
If your wrist runs under about 6.75 inches, the older 40.9mm case reads better than the 41mm and looks more like the watches people actually bought in the 2000s. Expect the same movement caveats. The trade-off is that stock is thinner and sellers sometimes ship the larger case because it photographs better. Ask for caliper photos across the lugs before you pay.
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Option three: the blue dial
Blue sunburst dials are harder to fake well than silver ones. The color shifts too gray or too purple under indoor light on cheap plating. A good blue is deep navy at the center and lifts to a brighter blue at the edges. If you can only judge from a seller photo, ask for a video under a desk lamp. That single clip tells you more than ten stills.
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Option four: skip the chrono
Honestly, the A7750 is the weak point. It runs, it usually keeps decent time, and it needs a service sooner than an automatic three-hand movement would. If you want the Portugieser look without that risk, buy a time-only Portugieser replica instead, or put the money into a better-made non-chronograph from a different line. Nobody has ever been called out for wearing a three-hand watch.
Where replicas fall short, every time
The date wheel font is usually a touch wide. The crown and pushers feel lighter and grittier than the real thing on a winding stroke. The rotor is louder than it should be. And water resistance is a guess, so don't swim in it, no matter what the listing claims. Service the movement if you plan to wear it daily, and don't run the chronograph constantly, because that wears the module faster.
What I'd ask before paying
- Close-up of the subdials to confirm the layout
- A short video with the chronograph started and stopped
- Case thickness measurement with calipers
- Dial photo under daylight, no filters
- Confirmation of which generation caseback you're getting
Do that and the odds of a disappointing delivery drop a lot. The pick is the 41mm two-register, and everything else on this list is a workaround.