IW371647 is an IWC reference in the Portugieser Chronograph line. A fake IW371647 copies the outside. It does not match the movement, case thickness, or subdial layout.

What is IW371647?

IW371647 is an IWC Portugieser Chronograph reference. The watch has a 41 mm stainless steel case. It is 13.1 mm thick. Water resistance is 30 m. The movement is the IWC calibre 69355. It runs at 28,800 vph. Power reserve is 46 hours. The dial has two subdials. One at 12 o'clock. One at 6 o'clock. The date window sits at 3 o'clock.

A fake IW371647 copies this layout. Most fakes do not match the movement. They do not match the case thickness. They do not match the dial printing.

Subdial layout

The genuine IW371647 has two subdials. The 12 o'clock subdial counts chronograph minutes. The 6 o'clock subdial runs the seconds. There is no 9 o'clock subdial. Many fakes use a Valjoux 7750 or a Seagull ST19. A 7750 has a 9 o'clock subdial. If you see a third subdial at 9, the watch is not a genuine IW371647.

Movement check

The IWC 69355 is an automatic column wheel chronograph. It has 231 components. It has 33 jewels. The rotor winds in both directions. A fake may use a 7750. The 7750 uses a cam system. It has a different winding feel. A fake may use a hand wound Seagull ST19. The ST19 has no rotor. Look through the sapphire caseback. The genuine movement has Geneva stripes. It has blued screws. It has a signed rotor. The fake movement may have rough finishing. It may have a blank rotor.

Case and crown

Genuine case thickness is 13.1 mm. Fakes often measure 14 mm to 15 mm. The extra thickness comes from the 7750 movement. The crown has an IWC logo. The pushers are polished. The lugs are 20 mm. The strap is alligator leather. The clasp is stainless steel. Fake clasps may have shallow engraving. Fake straps may use cowhide.

Dial and hands

The dial has applied numerals. The hands are leaf shaped. The chronograph seconds hand is thin. The subdial hands are small. Fake dials may have flat printing. The IWC logo may be off center. The date font may be wrong. The date wheel may not align. The sapphire crystal has anti reflective coating. Fake crystals may have no coating. They may reflect more light.

Caseback and serial

The caseback has a sapphire window. The reference IW371647 is engraved. The serial number is engraved. The engraving is deep and sharp. Fake engraving is shallow. The font may be wrong. The serial may not match IWC records. IWC does not publish a public serial database. A watchmaker can check the movement.

Price and market

Genuine IW371647 prices vary. Used examples trade on Chrono24 and at auction. Prices depend on condition, box, and papers. A fake sells for a small fraction. A low price is a signal. A full set with box and papers is a signal. A seller who avoids a movement photo is a signal.

What to do

Ask for photos of the caseback. Ask for a photo of the movement. Ask for the serial number. Ask for the reference number. Compare the subdial layout. Check the thickness. Check the date position. Meet at a watchmaker. Pay for an inspection. Do not rely on a box or papers alone.