Short answer: the IW371497 is a Portugieser Chronograph reference, and the better replicas of this watch are close enough that most people will not spot one from across a table. The tells show up in three places. The movement, the dial printing, and the strap. Fix those in your head before you shop and you will avoid the versions that fall apart in photos.
What the IW371497 actually is
It belongs to the Portugieser Chronograph family, a line defined by a large round case, a very thin bezel, and a dial with almost nothing on it. Two subdials sit on a vertical axis: a 30 minute counter at 12 and small running seconds at 6. The date sits at 3. A fine railway minute track runs around the outer edge, and the hour markers are applied rather than printed.
Case size lands around 41mm across with a thickness near 13mm, depending on the generation. Water resistance is modest, usually 3 bar, because this is a dress chronograph and not a diver. The caseback is sapphire and the movement is visible.
The trailing digits in an IWC reference usually point to a specific dial, hand, and strap combination rather than a different watch. So when you search this reference, expect to see the same base case with different dial colors, strap materials, and occasionally a bracelet.
Why this reference is easier to replicate than most
Here is the part that works in your favor. The genuine earlier Portugieser Chronograph ran a heavily modified Valjoux 7750, known internally as the calibre 79350. That movement already places a 30 minute counter at 12 and running seconds at 6, which is exactly the layout this dial needs.
That means a replica built on an Asian 7750 does not have to fake its subdial positions. They fall where they should. Compare that to a Daytona replica, where the subdial spacing is always slightly wrong because the movement geometry does not match. On a Portugieser, the proportions are in the right neighborhood from the start.
Newer genuine references moved to an in-house calibre with a longer power reserve, but the dial architecture stayed the same. Visually, the rep does not suffer for it.
The dial is where money is made or lost
A dial this empty has nowhere to hide. I look at these points first.
- Printing weight. The brand name and the words below it should be thin and crisp. Cheap reps print them slightly fat or slightly blurry.
- Railway track. The minute track lines should be even and sharp all the way around. Look at the 12 and 6 positions, where sloppy printing shows up first.
- Applied numerals. They should have polished edges that catch light and change appearance as you tilt the watch. Flat, dull markers read as fake instantly.
- Leaf hands. The shape matters more than the finish. Genuine leaf hands taper smoothly and have a defined spine.
- Subdial rings. Snailing or circular finishing on the subdials should be visible under light, not a flat disc.
- Date window. It should be cleanly cut with no rough edges, and the disc should be white with black text, not off white.
Case, crystal, and finishing
The Portugieser case is mostly polished with brushed flanks, and the bezel is thin enough that a bad polish job stands out. Run a finger along the lugs. Sharp edges where there should be a soft transition are a common flaw on budget tiers.
Crystal is a big one. Genuine watches use sapphire with anti reflective coating on both sides, which gives a slightly cool, almost invisible look. Some replicas coat only the outside, or use a coating with a strong blue or purple cast. Tilt the watch toward a window and check.
The crown should be engraved and should feel solid when you wind or set it. Loose, gritty crowns are a sign of a cheap movement holder.
Strap and clasp
Most versions ship on an alligator style leather strap with a tang buckle or a deployant. The strap is usually the weakest part of the package. Thin leather, uneven stitching, and a stiff feel are normal at lower price points. Many buyers swap it immediately, and honestly that is the single cheapest upgrade you can make.
If the seller shows a deployant clasp, ask for a photo of the inside. Good ones have proper engraving and a firm click. Bad ones feel like folded tin.
Pre-purchase checklist
- Ask for a running video, not just stills. You want to see the chronograph start, stop, and reset to zero.
- Confirm the subdial at 6 is running seconds, not a 12 hour counter. This is the most common functional error.
- Check the date flips cleanly at midnight.
- Request a close up of the dial printing at an angle.
- Ask about the crystal coating.
- Confirm the caseback engraving depth and that the movement is visible through sapphire.
- Ask what happens if the watch arrives dead. A seller who will not answer that is not worth the risk.
What no replica gets right
Be realistic about the ceiling. Movement finishing under the caseback will not match a genuine calibre. The leather will not feel like a hand stitched strap. The weight and the sound of the rotor differ slightly if you know what you are listening for. These are the things an owner notices and a stranger does not.
Bottom line
The IW371497 is one of the better replica targets because the dial layout and the movement geometry line up naturally. Spend your attention on the dial printing, the crystal coating, and the seller's willingness to show you a running video. Get those three right and you will be happy with the watch.