The short answer
A replica IW371654 copies the IWC Portugieser Chronograph. Judge it on measurements, not on photo lighting. The genuine watch is 41 mm wide, 13.1 mm thick, with a 20 mm lug width. A copy that measures 14 mm thick is a stock 7750 case with no rework. Ask for a caliper photo of the case flank before you send money. Expect to pay $350 to $700 for a mid tier example. Top tier sellers ask $800 and up.
Confirm the reference first
IWC lists the Portugieser Chronograph under several reference numbers, and dial colors change between them. Details for IW371654, such as dial color and case metal, should be checked against the IWC product page or an authorized dealer. If a seller cannot name the dial color for the reference, stop the deal. Many listings reuse one stock photo across three references.
Genuine specs to compare
- Case: steel, 41 mm wide, 13.1 mm thick
- Lug width: 20 mm
- Movement: IWC calibre 69355, automatic, 46 hours of power reserve
- Crystal: sapphire with antireflective coating on both faces
- Water resistance: 30 m
- Layout: small seconds and date at 6 o'clock, 30 minute counter at 12 o'clock
Faults common to replicas
- Case thickness above 14 mm, from an unmodified 7750 base
- Subdials at 12 and 6 that sit off the center line
- Date font too bold, date window cut too wide
- Applied numerals with flat tops and no bevel on the edges
- Printing too heavy on the IWC SCHAFFHAUSEN signature
- Caseback engraving shallow, sapphire too thin
- Strap stiff, stitch count wrong, buckle shape wrong
Six checks before payment
- Caliper photo of case width and thickness, taken on the watch.
- Macro of the dial at 12 and at 6. Check subdial spacing and the date window cut.
- Macro of the printing. Genuine strokes are thin and sharp.
- Movement photo. An Asia 7750 with a decorated rotor is the norm. Ask for the beat rate: 28,800 vph.
- Video of the chronograph start, stop, and reset to zero.
- Photo of the caseback engraving and the strap buckle.
What the movement means for service
The Asia 7750 is a known design. Parts are common, and a watchmaker can clean and regulate one. Plan on a service every three to five years if you wear the watch on most days. Water resistance on replicas is not tested at the factory. Do not swim with the watch. Have a watchmaker pressure test it first, then treat 30 m as splash contact only.
Price tiers
Under $200 buys a stamped dial, thin plating, and a rough chronograph reset. From $300 to $600 you get the correct case size, a sapphire crystal, clean printing, and an Asia 7750. From $700 to $1,000 the dial detail and the antireflective coating get closer to the genuine watch, and the case bevels are sharper. Above $1,000 you pay for small gains on a steel chronograph.
Bottom line
Ask for three photos and one video: case flank with calipers, dial macro, caseback, and the chronograph reset. Pay with a method that allows a dispute. A replica IW371654 is a copy, not an investment, and resale value is close to zero.