Short answer
A replica IW371696 succeeds or fails on three points: case thickness, subdial placement, and dial printing. The genuine Portugieser Chronograph runs a slim in-house chronograph movement inside a 41 mm case, so most replicas give themselves away by sitting too tall on the wrist or by spacing the two counters on the wrong axis. Measure the case, check the counter alignment, then move on to hands, crown action, and clasp hardware.
What the IW371696 is
The IW371696 belongs to the IWC Portugieser Chronograph family, a two-register layout with small seconds at 6 o'clock and an elapsed minutes counter at 12. The design language is spare: thin leaf hands, a rail track or tachymeter scale depending on the dial variant, and a case near 41 mm across and about 13 mm thick with a 20 mm lug width. Confirm the figures for your exact dial variant before you judge a replica, since dial colors, scale printing, and the presence of a date aperture change from one version to the next.
What to have on hand
- Reference photos of the genuine dial variant you want, showing front, case side, caseback, and clasp
- A caliper or a ruler with millimeter marks
- A 10x loupe
- The movement details for the replica you are considering
Step-by-step checks
- Measure the case across the bezel and stop at the crown, then compare the number to the 41 mm figure.
- Measure total thickness from the top of the crystal to the caseback, and treat anything past 14 mm as a warning sign of a thick modular movement.
- Rest the watch on a flat surface and view it from the side, watching for lugs that curve down toward the wrist instead of sitting parallel to the table.
- Draw an imaginary vertical line through the crown and confirm that both subdial centers sit on it.
- Inspect the dial print under the loupe and look for ragged numeral edges or a tachymeter scale that changes weight along its arc.
- Compare the hand shapes to your photos, checking that the leaf hands taper to a real point and that the small seconds hand reaches the inner track.
- Press each chronograph pusher in turn to confirm a firm click on start, stop, and reset with no grinding.
- Pull the crown to the setting position and turn it, feeling for backlash or a spongy response.
- Study the caseback engraving for depth and clean letterforms, since shallow stamping is a common shortcut.
- Flex the strap and work the deployant open and closed, noting any sharp edges or loose pivots.
Movement options
Most replicas of this reference fall into two groups. The first uses a modified Asian chronograph based on the 7750 architecture, which is reliable and easy to service but adds height to the case. The second uses a slimmer chronograph movement that copies the layout of the genuine calibre more closely, at a higher price and with fewer watchmakers willing to touch it. Ask which one you are buying. If thickness matters to you, pay for the slimmer option. If you want a movement any local shop can regulate, take the 7750-based build and accept the extra millimeter.
Dial and hand details
Look at the applied markers from a low angle. They should sit flat, hold a polished bevel, and cast a clean shadow. On the printed elements, check the brand text and the numerals for consistent stroke width. Hands deserve a separate pass: the center caps should be polished and centered, the minute hand should reach the rail track without overshooting it, and the chronograph seconds hand should reset to twelve every time. A hand that stops short of twelve on reset is a fault you cannot fix by hand.
Strap and clasp
The genuine watch ships on leather with a folding clasp. On a replica, check the strap thickness at the lugs, the evenness of the stitching, and whether the clasp closes with a single firm press. A flimsy clasp is the cheapest part of the build and the one you will touch every day.
Wearing and care
Keep the chronograph running only when you need it, since a permanently engaged chrono train adds wear. Have the watch pressure tested before you swim with it, even if the seller claims water resistance. Service intervals for these movements run longer than most owners expect, so a watch that gains a few seconds a day is normal, while one that stops overnight needs attention.