The IWC Portugieser collection is, without question, a classic etched into the very fabric of its DNA. Since the debut of the first model—Ref. IW3914—in 1998, its aesthetic has remained virtually unchanged; thanks to its balanced, elegant design and rich maritime flair, it has established itself as a modern classic spanning over two decades. In 2026, IWC broke with the material conventions of the Portugieser collection, introducing—for the first time—an all-black design crafted from high-tech Ceratanium. With the release of Model IW371631, the classic timepiece is infused with renewed vitality in a "dark mode" aesthetic.

The IWC Portugieser Chronograph Ceratanium (Ref. IW371631) carries forward the styling and proportions of its stainless steel and gold counterparts. Its 41mm diameter represents a "golden size" that appeals to both men and women; whether worn by a woman with a slender wrist or a man with an average-sized wrist, it never looks out of place. With a thickness of approximately 13mm (which feels even thinner on the wrist) and a lug-to-lug distance of about 47.9mm, the watch contours perfectly to the wrist's natural curve, ensuring a comfortable fit for daily wear that is free of any burdensome sensation—striking an ideal balance between aesthetic appeal and wearing comfort.

The classic details of the IWC Portugieser clone collection have been faithfully preserved: the extra-wide, beveled bezel, the iconic mushroom-shaped chronograph pushers, and the domed sapphire crystal—each element exudes a familiar sense of quality. The crystal features a double-sided anti-reflective coating that effectively minimizes glare, ensuring the time remains clearly legible even under bright lighting conditions (with the exception, of course, of the all-black dial—a point we will discuss in greater detail later). The only minor drawback is its water resistance rating, which remains at 30 meters; while sufficient for everyday tasks such as washing hands or handling splashes, the watch cannot be worn while swimming or showering—one of the very few minor shortcomings of this timepiece.

The undisputed highlight of this timepiece is its Ceratanium material—a high-tech alloy developed in-house by IWC. First introduced in the Pilot’s Watch collection, it now makes its debut in the Portugieser series, fundamentally transforming the watch's aesthetic character. The case, crown, chronograph pushers, and case back are all crafted from matte Ceratanium. Based on a specialized titanium alloy and subjected to high-temperature kiln firing, this material seamlessly combines the lightness and robustness of titanium with the extreme hardness and scratch resistance of ceramic. The immediate sensation upon strapping it on is one of sheer lightness; it feels significantly lighter than a steel model of comparable dimensions, ensuring a completely burden-free wearing experience, even over extended periods.

A "total black" design permeates the entire timepiece—from the case to the dial, and extending to the strap—creating a unified, dark aesthetic with striking visual impact. The matte black dial features black printed text, while the hands and indices are also rendered in black. However, the brand has thoughtfully applied a polished finish to the hands and indices; under illumination, they catch the light with a subtle sheen, creating a faint contrast against the matte dial that just barely suffices to ensure basic legibility. It must be stated objectively, however: while this all-black design boasts maximum visual appeal and an undeniably cool factor, its lack of contrasting accents means that legibility is, admittedly, not its strong suit.

The IWC-manufactured Calibre 69355 movement. Jointly developed and produced at the Richemont Group’s central manufacturing facility in ValFleurier, this high-quality, in-house movement features a double-pawl automatic winding system that boasts exceptional efficiency, allowing the watch to rapidly build up its power reserve. Furthermore, it integrates a column-wheel chronograph mechanism, ensuring smooth and fluid operation while guaranteeing enhanced precision. With a frequency of 4 Hz (28,800 vibrations per hour) and a power reserve of approximately 46 hours, the movement requires no frequent manual winding during daily wear, making it perfectly suited to meet the demands of everyday use.