Answer first
The fastest test on a fake IW371701 is the subdial layout. The second fastest is the caseback. A real IWC Pilot's Watch Chronograph ref. IW371701 runs its chronograph minutes at 12 and its running seconds at 6, with a day and date window at 3. Copies built on a stock 7750 layout give you running seconds at 9 and a 12 hour totalizer at 6 instead. That is visible from arm's length, no loupe needed.
If the layout is right, flip the watch over. The calibre 79320 in a genuine one is a modified Valjoux 7750, decorated and engraved, and that engraving is cut into the metal. Most copies print it, stamp it shallow, or slap a sticker on the rotor.
What the IW371701 actually is
IWC built the 3717 generation from roughly 2006 to 2012. Steel case, 42mm across, matte black dial, white luminous numerals, soft iron inner cage for magnetic protection, day and date at 3, 60m water resistance, sapphire crystal with coating on both faces. It was the workhorse pilot chrono in the lineup, and that is exactly why the copy trade went after it. The dial is simple enough to photograph well and the watch is famous enough to sell itself.
Why the copies are everywhere
A used steel 3717 sits in the low to mid four figures. A replica costs a fraction of that. The whole business model lives in that gap, so sellers have had fifteen years to refine the details. Assume any cheap one is wrong until proven otherwise.
The five-minute check
- Measure it. Genuine is 42mm wide and about 14.5mm thick. Many copies come in at 43mm or more, and feel slab-sided.
- Look at the subdials. Minutes at 12, running seconds at 6. Wrong layout, walk away.
- Read the day and date. The fonts on a real disc are thin and even, sitting dead centre in the window. Copies use fat fonts and the day often sits high or low.
- Check the dial print. "IWC" and "SCHAFFHAUSEN" are sharp under magnification. Copy print looks slightly fuzzy at the edges, like a good laser printer.
- Look at the crystal at an angle. Double anti-reflective coating gives a faint blue tint and kills reflections. Single coated or uncoated glass looks flat and mirror-like.
Case, crystal and the soft iron cage
The soft iron inner cage is the part copy makers skip because it costs money and nobody sees it. It also adds weight. A real 3717 feels denser than its size suggests, and the caseback sits proud because there is a second shell underneath. If the watch feels hollow or light, that is a tell on its own.
Case finishing is another one. Genuine brushing runs in one consistent direction across the lugs, and the polished bevels are crisp. Copies polish the whole lug and call it a day. Run a fingernail along the lug edge. A real one catches; a fake slides.
Dial and hands
- The applied numerals are faceted metal with lume fill, set flat and level against the dial. Loose or tilted numerals are a bad sign.
- The triangle at 12 has two lume dots either side, both filled cleanly. Copy lume is often lumpy or off-white.
- Hands are sword shaped with a proper counterweight on the chrono seconds. Thin, stamped hands with a stubby counterweight belong to a $200 watch.
- Lume on a genuine one glows evenly and fades. On a copy it either does nothing or glows like a toy for ten minutes.
Movement and caseback
Ask for a movement photo at 10x before you commit to anything. The 79320 should show Geneva stripes on the bridges, blued screws, and a rotor engraved with IWC's Probus Scafusia mark. The engraving has depth. On copies it looks sandy or sits on top of the surface. You may also see the wrong jewel count, mismatched finishing between bridges, or a rotor that does not match the case metal.
The caseback itself is solid steel with deep engraving and a serial between the lugs. Edges on the lettering should be sharp enough to feel. A laser-etched back looks grey and shallow under a light, and the serial is often the same number on every copy from a batch.
Where the cheap ones fall apart
- Subdial spacing too wide or too narrow against the centre
- Day and date font too heavy, misaligned in the window
- Case thickness over 15mm
- Pushers that feel mushy or wobble
- Crown engraving shallow or missing
- Strap hardware without a clean signature, or stitching that wanders
Questions worth asking a seller
- Can you send a photo of the movement with the caseback off?
- What is the exact case measurement, lug to lug and thickness?
- Is the serial visible between the lugs, and does it match the papers?
- Will you accept a return if my watchmaker says the movement is not an IWC calibre?
Anyone who dodges the movement photo is telling you something.
Bottom line
A replica is a watch that looks right in a photo and feels wrong on the wrist. If you want the look for cheap, buy it knowing what it is. If you are paying real 3717 money, insist on the movement shot and get it opened by a watchmaker before the return window closes. The subdial layout and the caseback will settle the question in under five minutes, and everything else is confirmation.