Fake IW371446: the short answer
A counterfeit IW371446 gives itself away in four places: case finishing, chronograph behavior, movement finish, and engraving quality. The genuine watch is a 41 mm stainless steel Portugieser Chronograph with a 30-minute totalizer at 12 o'clock, running seconds at 6 o'clock, no date window, and the IWC calibre 79350 inside. Most fakes copy the layout and fail on the mechanics. Test the chronograph first, then work outward to the case, dial, and paperwork.
Before you inspect
- 10x loupe and a diffused light source
- Digital calipers for diameter and thickness
- High-resolution photos of a known-genuine IW371446 for side-by-side comparison
- Permission from the seller to operate the pushers and handle the watch
Step-by-step authentication checks
- Measure the case with calipers. A genuine IW371446 sits at roughly 41 mm across and about 12.3 mm thick. Fakes often run 1 mm large or sit noticeably thicker because of a cheaper movement spacer.
- Press the upper pusher and watch the center chronograph hand start. It should move in small, clean increments with no stutter or lag.
- Press the lower pusher to reset. The hand must snap back to zero in one motion. A hand that drifts, overshoots, or needs a second press points to a low-grade quartz or poorly finished automatic module.
- Check the sub-dials. The 30-minute counter sits at 12 and the running seconds at 6. On fakes, the sub-dial hands often rest slightly off the 12 and 6 markers, or the two counters are swapped.
- Look for a date window at 3 o'clock. The IW371446 has none. Any date aperture is an immediate fail, no further inspection needed.
- Examine the dial printing with the loupe. The "IWC SCHAFFHAUSEN" text should be crisp with sharp edges and no ink bleed. Fake printing looks soft or slightly bold.
- Study the applied numerals and hands. Genuine examples have polished bevels that catch light along a single clean line. Fake markers show rounded edges and cloudy polishing.
- Turn the watch over and compare the caseback engraving to reference photos. Check font weight, engraving depth, and the position of the reference number. Laser-etched fakes look shallow and gray next to a stamped or deep-engraved original.
- Match the serial number on the caseback to the warranty card and any service paperwork. A mismatch or a missing card is a serious warning sign.
- Inspect the strap and buckle. Genuine alligator has a fine, irregular scale pattern and the buckle engraving is deep and even. Fake straps use embossed calfskin with repeating scales.
- Weigh the watch. Steel IW371446 examples land in a narrow range. A noticeably light watch suggests a hollow case or a plated base-metal construction.
Movement checks
The calibre 79350 is a modified Valjoux 7750 base with a chronograph module layout unique to IWC. Ask the seller for a clear photo of the movement through the caseback, or have a watchmaker open it. Look for Geneva stripes with clean, straight edges, blued screws with polished slots, and a rotor engraving that is cut, not printed. Fake movements show wavy striping, painted rotor text, and rough perlage under the balance.
Common fake tells
- Chronograph seconds hand that hesitates on start and resets short of zero
- Sub-dial spacing that crowds the center of the dial
- Dial text that sits too low or too close to the sub-dials
- Case flanks with soft transitions instead of a sharp, polished bevel
- Pushers that feel mushy or sit proud of the caseband
- Caseback screws with off-center slots or mismatched heads
If the watch fails a check
- Stop the transaction and do not send payment.
- Photograph the specific failure point for your records.
- Report the listing to the platform if the seller described the watch as genuine.
- Have any watch you already own verified by an authorized IWC service center before resale.