A fake IW371788 is easy to spot once you know where the money went on the real watch. The short version: cheap copies fail on the dial printing, the subdial spacing, the caseback engraving, and the way the chronograph runs. Good replicas get most of those right and usually give themselves away on the movement, the crown action, and the strap. Everything below is what I actually check, in order, before I would call a copy decent.
What this reference is, in plain terms
The IW371788 sits in IWC's Portugieser chronograph family: a clean, flat-bezel case, a wide dial with two subdials, leaf-shaped hands, and applied markers rather than printed ones. Because the design is so simple, it is brutally hard to copy. There is nothing to hide behind. No busy bezel, no skeleton work, no texture. A crooked marker or a fat numeral has nowhere to go.
That is also why fakes of this reference range from embarrassing to genuinely convincing. The gap is not in the overall shape. It is in the small stuff.
The tells I check first
1. Dial printing and numeral thickness
Look at the minute track and the text under 12. On a real one the printing is thin, crisp, and sits at the same height across the dial. On a weak fake the lettering looks slightly bold, the spacing between letters drifts, and the minute hashes get chunky toward the edges. Zoom in with a phone camera. It shows up immediately.
2. Subdial spacing and hand length
The two subdials have to sit on the right axis and the hands inside them have to reach the track. A lot of copies use a movement with a different subdial geometry, so the counters end up a hair too close together or too far apart. Owners notice this before anything else. If the small hands stop short of the marks, walk away.
3. Case and lug finishing
Run a fingernail along the lug edges. Real IWC brushing is even and the transitions between brushed and polished surfaces are sharp. Fakes either round those transitions off or leave a burr. The lugs also tend to be a touch thicker than they should be, which changes how the watch sits on the wrist.
4. Caseback engraving and serial fonts
Engraving is where budget copies collapse. The lettering is shallow, the spacing is uneven, and the serial is stamped in a font that does not match the reference. Compare against photos of a real caseback taken straight on, not at an angle.
5. How the chronograph behaves
Start and stop the chronograph a few times. The pushers should feel firm with a clean snap, not mushy or gritty. Reset should return both hands to zero instantly and repeatably. Many fakes use a modified third-party chronograph movement, and the giveaways are a stuttering seconds hand, a reset that lands a fraction off zero, or pushers that feel like they are pushing through sand.
Crystal, weight, and strap
A proper sapphire crystal with anti-reflective coating almost disappears under light. Fakes often show a blue or purple wash at an angle. Weight is a rough guide only, since a steel case is a steel case, but a copy that feels top-heavy or rattles when you shake it gently is telling you something about the internals. The strap is usually the cheapest part of a replica. Stiff leather, shiny edges, and a buckle with soft engraving are common.
What a good replica still will not do
It will not have the in-house movement architecture, so a display back is a losing proposition. It will not match the servicing behavior of the real caliber, and the crown will not have quite the same thread feel when you wind it. If those things matter to you, no replica solves them. If what you want is the look on the wrist and the dial doing its job in daylight, a well-made copy gets close.
Questions worth asking a seller
- Which movement is inside, and is the subdial layout native to it?
- Are the photos of the actual piece or stock images?
- Can you show a straight-on shot of the dial and the caseback?
- What is the return policy if the chronograph resets off zero?
Ask for a short video of the chronograph running and resetting. Anyone selling a decent fake will send one without arguing.