Short answer
A replica IW371790 is a copy of the IWC Portugieser Chronograph. Supply comes from several factories, and each one sells more than one grade. Three items decide whether a sample is worth the money: the dial, the case and the movement. Buy the grade with a correct case width, a working chronograph and clean print. Skip any sample with painted subdials or a glued date window.
What the reference is
The Portugieser Chronograph runs on IWC calibre 79350, a reworked Valjoux 7750. The dial is bicompax: a 30-minute counter at 12, small seconds at 6, date at 3. Hands are leaf shaped. Numerals are applied, not printed.
Public spec sheets for the -90 suffix are thin. Confirm dial color, strap and case finish with the seller in writing before you order. Ask for the factory name and the batch date.
Dial checks
- Subdial spacing. The two counters sit on a vertical line through the center. Offset or crowded counters point to a small movement in a large case.
- Print. Look at the minute track under a loupe. Genuine print holds a sharp edge at 10x. Bad print bleeds.
- Date window at 3 sits in a stepped frame. A flat window with no step is a tell.
- Numerals should catch light on the top face and show a polished bevel. Flat, dull numerals read as plated brass.
- Hands: leaf shape, even width on both sides, no burr at the tip.
Case and finish
Portugieser Chronograph cases measure about 41 mm across. A sample that reads 43 mm or 44 mm on calipers is the wrong case. Check lug width, crown size and the polish line where the bezel meets the case band. Run a finger over the caseback engraving. Laser etch sits flush with the surface. Stamped text leaves a ridge.
Movement
Most replicas run an Asian 7750. That movement beats at 28,800 vph and drives the 30-minute counter at 12 the same way the genuine does. Two tests. Start the chronograph and watch the sweep hand for stutter. Then reset and confirm the counter snaps back to zero in one move. A clone with a decorated rotor costs more and sits closer to the 79350 look through a display back.
Before you pay
- Ask for photos on a plain background, chronograph running at 12:00:00.
- Request caliper shots of case width and lug width.
- Confirm the water resistance claim. Most replicas use a push-in caseback and carry no tested rating.
- Ask which movement is inside, A7750 or a clone, and who services it.
- Ask the return window in days, not in words.
Limits
A replica is not a genuine watch. It carries no IWC warranty, no service record and limited resale value. Service on an A7750 needs a watchmaker who stocks 7750 parts. Budget for that cost at the time of purchase.