A fake IW371615 fails in four places you can check in minutes: the movement visible through the sapphire case back, the anti-reflective coating on the domed crystal, the depth and font of the case-back engraving, and the sharpness of the dial printing. The genuine IWC Portugieser Chronograph IW371615 uses IWC's in-house calibre 69355 inside a 41 mm stainless steel case with a blue dial and a see-through back. If the watch has a solid steel back, or a rotor without IWC finishing, it is not genuine.
What is the IWC Portugieser Chronograph IW371615?
The IW371615 is the stainless steel Portugieser Chronograph with a blue sunburst dial, a vertical two-counter layout, and IWC's own chronograph movement. It measures about 41 mm across, roughly 13 mm thick, and takes a 20 mm alligator strap with a steel pin buckle.
Inside sits calibre 69355, an automatic chronograph with IWC's Pellaton winding system, a column wheel, 46 hours of power reserve, and a 4 Hz beat rate. IWC displays it through a sapphire case back.
How can you spot a fake IW371615 quickly?
1. Movement and case back
Genuine 69355 movements show fine striping, polished screw heads, and crisp engraving on the rotor and bridges. Most replicas hide a Seagull ST19 or a 7750-derived clone under a rotor with flat, shallow lettering. Photograph the movement in good light and compare the finish with official IWC images before you commit.
2. Crystal and reflections
The genuine crystal is sapphire, box-domed, and coated on both sides, so the dial looks nearly invisible at most angles with a faint blue tint near the edges. Fakes usually skip the inner coating, which leaves a grey haze or a hard reflection across the dial. Tilt the watch toward a window and watch how the light behaves.
3. Dial printing and layout
Authentic printing is dense and even, with thin strokes and no ink bleeding into the dial finish. The blue dial has a fine sunburst grain that shifts from deep navy to bright blue as you rotate it. Check that the layout matches the reference sheet exactly, because extra apertures such as a date window at 3 o'clock mean the watch is not an IW371615.
4. Case, crown, and pushers
Genuine cases have sharp, polished bevels, clean lug edges, and spring bars that sit flush. The chronograph pushers should start, stop, and reset with a light, clean click and no grinding. A crown that wobbles or a pusher that feels mushy points to a cheap movement inside.
5. Strap, buckle, and packaging
Authentic alligator straps carry a maker's stamp on the lining and taper evenly to a signed steel pin buckle. Replica straps use embossed cowhide with printed grain and buckles with soft engraving. Boxes and papers are easy to copy, so treat them as supporting evidence rather than proof.
Are high-end replicas of the IW371615 any different?
Better replicas copy the case shape, dial color, and strap closely and can fool a glance across a table. They still fail on the movement, the crystal coating, and engraving depth, and they remain counterfeits of an IWC trademark. Buyers who want the real 69355 experience usually choose a genuine pre-owned example instead.
Does price reveal a fake IW371615?
A genuine steel Portugieser Chronograph on leather retails in the mid four figures and trades used in the mid to upper four figures. Replicas of the same reference sell for a few hundred dollars. A new in box full set IW371615 at a fraction of retail price is a fake, or a stolen watch.
How do you verify an IW371615 before buying?
Ask for macro photos of the movement, the case-back engraving, and the dial text, plus the case number and any service paperwork. Have an independent watchmaker or an IWC service center open the watch and confirm the calibre, because a movement check settles the question. A seller who refuses a movement inspection is telling you something.
Quick checklist
- Sapphire back with a finished in-house calibre 69355
- Double-coated domed crystal with minimal reflection
- Sharp, dense dial printing and a true sunburst blue finish
- Clean pusher action and a firm, non-wobbling crown
- Deep, crisp case-back engraving with matching numbers
- Maker-stamped alligator strap and signed buckle
- Price consistent with the genuine market