Short answer
A fake IW376031 fails four checks: the chronograph counter at 12 o'clock, the flyback reset, the case thickness, and the movement finish under the display back. The genuine watch runs IWC calibre 89360. Most replicas run a modified ETA 7750 or a Chinese clone of that movement. The two calibres put the chronograph hands in different places, so a photo of the dial settles the question in most cases.
The reference in numbers
- Model: IWC Da Vinci Chronograph, ref. IW376031
- Case: stainless steel, 42 mm diameter, thickness near 14 mm
- Movement: IWC calibre 89360, automatic, 4 Hz, 68-hour power reserve
- Functions: hours, minutes, small seconds, flyback chronograph, date
- Status: discontinued, listed in the IWC archive and not the current catalog
Confirm each figure against IWC archive data for the exact serial before money changes hands. Reference databases copy each other, and errors spread.
Check 1: the 12 o'clock counter
Calibre 89360 combines elapsed hours and minutes on one subdial at 12 o'clock. One hand counts minutes. A second hand on the same register counts hours. A 7750-based replica puts a 30-minute counter at 12 and a 12-hour counter at 6. Look at the subdial at 6 o'clock. On the genuine watch it holds running seconds.
Check 2: the flyback
Start the chronograph and let it run 20 seconds. Press the lower pusher without stopping the timing first. The 89360 resets to zero and restarts on that single press. A 7750 clone stops the timing and needs a second press to reset. Run this test on a dealer bench before you pay.
Check 3: case and weight
Measure the case with calipers. Replica cases for this reference run thicker than the original and sit between 15 mm and 16 mm. A steel watch of this size on a leather strap weighs about 95 g to 105 g on a kitchen scale. A reading under 85 g points to a thin caseback or a light movement spacer.
Check 4: the movement
Look through the sapphire back. The 89360 shows striped bridges, a signed rotor, and engraved lettering cut into the metal. Replica movements show laser etching that sits on the surface, screw heads with burred slots, and rotor print that fades at the edges. Ask for a sharp photo of the balance cock and the rotor hub.
Price reality
Genuine IW376031 watches trade on the secondary market at about $5,000 to $8,000 USD. The figure moves with box, papers, and service history. Replicas sell for $250 to $700. A listing at $900 for a full set is not a discount. Treat it as a warning.
What photos cannot confirm
Dial printing, lume color, and strap stitching change between replica batches. Ask for a video of the flyback test and a photo of the movement with the caseback removed. If the seller refuses either request, stop.