Short answer: A replica IW3717 is a copy of the IWC Portugieser Chronograph reference IW3717. The best replicas match the 41 mm steel case, the twin subdials at 12 and 6, the date window at 3, and the 7750-based chronograph layout. Evaluate the case profile, dial printing, date font, subdial spacing, and movement hand stack before you buy. A correct replica should not have a running seconds hand at 9 or a date at 4:30.

Prerequisites

  • Know the genuine IW3717 layout: about 41 mm case, chronograph, small seconds at 6, 30-minute counter at 12, date at 3.
  • Use a loupe or macro photos for dial and date checks.
  • Ask for a movement photo and a short video of chronograph start, stop, and reset.

Step-by-step inspection

  1. Measure the case across the bezel without the crown. The target is about 41 mm, and the thickness should sit near 12.6 mm. A 43 mm or 14 mm thick case is a different copy.
  2. Check lug shape and curve. The IW3717 has straight, slender lugs with a sharp inner bevel. Soft or thick lugs point to a lower-grade case.
  3. Verify the dial layout. The small seconds sits at 6, the 30-minute chronograph counter at 12, and the date at 3. Any subdial at 9 or date at 4:30 is an instant fail.
  4. Inspect subdial spacing. The two counters should sit close to the center line and align with the vertical axis. Wide spacing or counters that touch the minute track look wrong.
  5. Read the date font under magnification. The genuine IW3717 uses a clean, narrow font with straight numerals. Fat, rounded, or off-center date wheels are common replica flaws.
  6. Check the printing. IWC and Schaffhausen should be crisp, level, and spaced correctly. Look for thick strokes, ink bleed, or a tilted logo.
  7. Look at the hand stack. The chronograph center seconds hand should sit above the hour and minute hands. A low or rubbing hand stack causes reset drift.
  8. Test the chronograph. Start, stop, and reset the chronograph three times. The center seconds hand should return to 12 without wobble, and the minute counter should advance in one-minute steps.
  9. Ask for the movement photo. The genuine IW3717 uses calibre 79320, a 7750-based movement with central chronograph drive and cam actuation. Decorated plates help less than a correct hand stack and firm pusher feel.
  10. Confirm the crown and pushers. The crown should be signed and sit flush. Pushers should have a firm start-stop feel and a distinct reset click.

Common red flags

  • Case size listed as 42 mm or 43 mm.
  • Date window at 4:30.
  • Running seconds at 9.
  • Printed subdial rings instead of recessed rings.
  • Caseback engraving that is shallow, uneven, or misspelled.
  • Seller who refuses a movement photo or a reset video.

What matters most

Prioritize case dimensions, dial layout, and chronograph function. A replica with a correct 41 mm case and a clean 12/6/3 layout looks closer on the wrist than one with a decorated movement and wrong geometry. Weight and bracelet finish are secondary because the IW3717 is often worn on leather. Confirm the strap width at the lugs, usually 20 mm, and check that the spring bars engage the lug holes without play.