The IWC Portugieser Chronograph ref. IW371747 is a 41 mm stainless steel chronograph with a bi-compax layout, applied numerals, and the in-house calibre 69355. Fakes of this reference circulate in large numbers, and most fail on four points: dial printing, hand color and finish, case geometry, and the movement visible through the sapphire caseback.

What gives a fake IW371747 away fastest?

Start with the subdials. A genuine IW371747 runs a 30-minute counter at 12 o'clock and small seconds at 6 o'clock, with the date at 3. Cheaper counterfeits often shift this layout or drop a running seconds hand at 9 o'clock, which is instantly wrong for this reference.

Dial printing and applied numerals

Genuine dials use applied, polished numerals that cast a hard shadow at an angle. Fake dials usually carry flat printed indices, or applied markers with dull, rounded edges. The lines of "IWC Schaffhausen" and "International Watch Co" should be razor sharp under a loupe, with no ink bleed or double strike.

Hands and subdial rings

Real leaf hands are heat blued, so the color shifts from near black to deep blue depending on the light. A single flat blue tone that never changes is a counterfeit marker. Subdial rings on the genuine watch are crisp, evenly spaced, and perfectly concentric.

Case, lugs, and pushers

Authentic cases alternate brushed and polished surfaces with defined, sharp transitions. Fakes usually show soft lug edges, uneven brushing, and pushers that sit slightly out of line with the crown. The crown and pushers should click firmly, not travel with a spongy feel.

Caseback, engraving, and serial

Engraving on the genuine caseback is deep, even, and machine cut, with the reference and case numbers in a matched sequence. Shallow laser etching that catches light unevenly is typical of counterfeits. A serial that does not return a record at an IWC boutique or service center is the single strongest warning sign.

Movement and rotor

Real calibre 69355 shows Geneva stripes, circular graining, blued screws, and a column-wheel chronograph mechanism under the sapphire back. Most fakes hide an Asian 7750 or Seagull ST19 behind decorative plates screwed on top. If the rotor spins loudly or the chronograph stutters at start, walk away.

Weight, crystal, and feel

The genuine watch sits around 80 to 90 grams on a leather strap, and the sapphire crystal carries an anti-reflective coating with a faint blue sheen at an angle. A missing AR coating, or a crystal that feels like plastic, points to a fake. Always handle the watch before paying: a light, hollow case that rattles is not a 41 mm steel IWC.

Which details do most replica IW371747 builds get wrong?

• Subdial spacing and the exact position of the date window.
• Applied numeral height, polishing, and shadow depth.
• Heat-blued versus painted blue hands.
• Caseback engraving depth and the logic of the serial sequence.
• Movement finishing and the feel of the chronograph pushers.

How much should a genuine IW371747 cost?

Steel Portugieser Chronograph models retail in the mid to high four figures in US dollars, and complete sets on the secondary market typically trade below retail. A price far under market, especially one without box and papers, usually means a fake or a stolen watch. Treat any "new, unworn, no papers" offer as a red flag.

Can a jeweler confirm a fake in minutes?

An experienced watchmaker can usually flag the common tells in a few minutes, but a definitive answer comes from an IWC service center or boutique. They can match the serial to the reference, check warranty status, and open the case back. Get written confirmation before you buy or return, not a verbal opinion.

Frequently asked questions

Is the IW371747 faked often?

Yes. Popular steel chronographs from major Swiss brands are copied heavily, and the Portugieser line is no exception. Quality ranges from obvious junk to convincing super clone builds, which is why serial verification matters more than photos.

Do box and papers prove authenticity?

No. Boxes, manuals, and warranty cards are widely counterfeited and sold separately online. Papers help only when the serial matches the watch and the dealer stamp can actually be verified.

Should I buy a replica IW371747 instead?

That call is yours. Understand that fakes do not hold value, cannot be serviced by IWC, and are illegal to import into the US. Buy only from sellers who disclose exactly what the watch is and price it accordingly.