Quick answer
The IW371416 sits in the IWC Portugieser Chronograph reference 3714 family: a 40.9 mm stainless steel chronograph with two subdials, feuille hands, and the caliber 79350 movement. Replicas of this reference exist, and four checks separate most of them from the real watch. Measure the case diameter, confirm the subdial positions, feel the chronograph pushers, and read the caseback engraving. A counterfeit rarely passes all four.
What the IW371416 is
The 3714 line arrived in 1998 and became the reference most people picture when they hear Portugieser Chronograph. The layout is clean: small seconds at 6 o'clock, a 30 minute counter at 12, applied numerals, a railroad minute track on the flange, and leaf shaped hands. The case measures 40.9 mm across, 12.3 mm thick, with a 20 mm lug width and 3 bar water resistance. The movement is the caliber 79350, built on the Valjoux 7750 base, running at 28,800 vibrations per hour with 31 jewels and a 44 hour power reserve. The reference number and a serial number are engraved on the caseback.
Before you start
- A digital caliper that reads to 0.01 mm
- A 10x loupe
- A kitchen scale accurate to 1 gram
- A spring bar tool or a watchmaker who can open the case
- A reference photo of the genuine watch from a dealer listing or the manufacturer
How to check an IW371416
- Measure the case across the bezel at the widest point. The genuine measurement is 40.9 mm. Many replicas come in at 41.5 mm or 42 mm because they reuse a generic case.
- Measure the lug width. It should read 20 mm. A 21 mm or 22 mm reading points to a stock case.
- Check where the subdials sit. Small seconds belong at 6 o'clock and the chronograph minute counter at 12. Replicas often shift these to 3 and 9 or widen the spacing.
- Study the dial printing under the loupe. Genuine text is thin and sharp with clean edges. Counterfeit printing looks heavier and slightly blurred, and the minute track loses definition.
- Look at the hands from the side. Genuine feuille hands are beveled and polished on the facets. Replica hands are flat stamped metal.
- Inspect the date aperture at 3 o'clock. The cut should be clean with no white plastic frame around the window.
- Press the chronograph pushers. Genuine travel is short and firm, with a crisp reset to zero. A spongy or long throw suggests a quartz module or a low grade 7750 copy.
- Wind the crown about 30 turns and listen. The genuine movement winds smooth with no grinding or grit.
- Flick the watch gently side to side and feel for rotor wobble. The 7750 base produces a slight rotational sway. A quartz replica has no rotor at all.
- Weigh the head on the scale. Steel 3714 watches land in a narrow band that depends on the strap, so treat weight as a supporting clue rather than a verdict.
- Turn the watch over and read the caseback. The reference IW371416 and a serial number should be engraved, not printed, with even depth and correct alignment.
- Check the crystal. It should be box shaped sapphire with a clear anti reflective treatment. Flat mineral glass with a purple or blue haze is a strong warning sign.
- Ask a watchmaker to open the case and confirm the caliber 79350, including the rotor engraving and jewel count.
Red flags
- A case diameter that lands on a round number instead of 40.9 mm
- Subdials that do not sit on the 12 and 6 axis
- Printed rather than engraved caseback text
- A seconds hand that ticks once per second
- A seller who refuses an inspection by a third party watchmaker
- No box, papers, or service history on a watch priced near market
Limits of a visual check
Case and dial checks catch most replicas, but they cannot catch everything. A franken watch can pair a genuine case with a swapped movement, and a well finished copy can fool a photo comparison. Confirm the serial with the manufacturer, buy from a seller who allows a return window, and pay for a movement inspection before money changes hands. On this reference the movement is the hardest part to fake, so that inspection carries the most weight.