IWC Portugieser Eternal Calendar

For over 150 years, IWC Schaffhausen has been a leading manufacturer of luxury watches, renowned for their precision engineering and timeless designs. The company's dedication to innovation and quality has earned it a loyal following among watch collectors and enthusiasts around the world.

One of IWC's most celebrated collections is the Portugieser. Launched in 1939, the Portugieser was originally designed to meet the demands of the Portuguese maritime industry. The watch featured a large size, a clear dial, and robust construction, making it an ideal timepiece for navigating the open seas. Over the years, the Portugieser has evolved into a more versatile collection, while still retaining its signature maritime heritage.



In 2024, IWC Schaffhausen unveiled the latest addition to the Portugieser collection, the Portugieser Eternal Calendar. This remarkable timepiece represents a significant leap forward in watchmaking technology. While traditional perpetual calendars are complex mechanisms that can track the date, day, month, and year for centuries, they typically need to be adjusted every 100 years that are not leap years. The Portugieser Eternal Calendar, however, is the world's first secular perpetual calendar. This ingenious complication automatically takes into account the Gregorian calendar's leap year exceptions, meaning that it will display the correct date for thousands of years to come.

The Portugieser Eternal Calendar features a stunning design that is both elegant and functional. The watch has a 44.4 mm platinum case with a polished and brushed finish. The white lacquered glass dial features black Arabic numerals and leaf-shaped hands, which provide excellent legibility. The subdials for the day, date, month, and power reserve are arranged symmetrically around the center of the dial, while the moon phase display is located at 6 o'clock.



The Portugieser Eternal Calendar is powered by the IWC-manufactured 52640 caliber, a self-winding mechanical movement with a Pellaton automatic winding system. The movement has a power reserve of 7 days, and it is visible through the sapphire crystal case back. The watch is completed by a black alligator leather strap from Santoni.

Let's take a closer look at the dial of the Portugieser Eternal Calendar. The white lacquered glass dial is the most striking feature of the watch. This innovative component creates a sense of depth and dimension, and it allows the black printed numerals and applied indices to seem to float above the surface of the dial. The subdials are arranged in a classical Portugieser style, with the day subdial at 3 o'clock, the date subdial at 12 o'clock, the month subdial at 6 o'clock, and the power reserve subdial at 9 o'clock. The moon phase display at 6 o'clock is particularly impressive. It features a double moon disc that rotates to depict the phases of the moon with remarkable accuracy.

Powering this masterpiece of horology is the IWC-manufactured caliber 52640. This in-house mechanical beast consists of 410 components, all meticulously engineered to deliver both chronographic precision and aesthetic appeal. It operates at a frequency of 28,800 vibrations per hour (4 Hz) and boasts an impressive power reserve of seven days. Thanks to the Pellaton automatic winding system, harnessing even slight wrist movements into usable power, it'll keep ticking even when you're not wearing it for an extended period.



The 52640 isn't just about efficiency; it's a feast for the eyes. The movement is visible through the stunning sapphire crystal caseback, showcasing its intricate parts and refined decoration. The rotor, emblazoned with a solid gold medallion, adds a touch of understated opulence. This level of attention to detail speaks to IWC's commitment to crafting timepieces of lasting beauty as much as they are marvels of engineering.

The Portugieser Eternal Calendar makes waves not because it is a perpetual calendar, but how it redefines the complication. Traditionally, perpetual calendars require correction at the end of non-leap-year centuries, as the Gregorian calendar dictates. The average perpetual calendar can't account for those missing leap days.

IWC's solution is as straightforward as it is groundbreaking: a "400-year gear." This additional element within the intricate dance of wheels and gears makes a single, complete revolution every four centuries. It's designed to override three of the missing leap days, leaving the watch blissfully accurate for centuries, even millennia. There won't need to be any fiddling with the watch in 2100, 2200, or 2300.



And if you think that's impressive, wait till we talk about the moon.

Perhaps the most visually arresting feature of the Portugieser Eternal Calendar is the "Double Moon™" display at the 6 o'clock position. This isn't your average moonphase complication – it's the result of IWC engineers aiming for lunar perfection.

Through intensive simulations covering trillions of gear combinations, they developed a reduction gear train with three intermediate wheels. The result? A moonphase display so precise it'll only deviate from the actual lunar cycle by a single day after about 45 million years. You'll have to take their word for it as you aren't likely to be around to check that accuracy for yourself!

The "Double Moon™" features a starry titanium base with two blue dots representing the moon. Atop this, a glass disc rotates, displaying the moon's waxing and waning for both the Northern and Southern Hemispheres. It's a captivating dance to behold as it's both visually striking and a testament to IWC's obsessive pursuit of precision.

The IWC Portugieser Eternal Calendar isn't a watch for everyone, and it certainly doesn't come cheap. However, for true connoisseurs, it's more than a wristwatch – it's a tangible symbol of the pinnacle of horology. A timepiece like this showcases not only IWC's commitment to the craft, but it also pushes the envelope on what's achievable for high-complication timepieces.



The secular calendar complication guarantees incredible accuracy, removing the need for any but the most exceptional of circumstances where manual adjustments are required. The moonphase is a feat unto itself, promising to keep near-perfect celestial time on your wrist for longer than any of us have the privilege to observe.

Every inch of the Portugieser Eternal Calendar is brimming with quality. From its gleaming platinum case to the meticulously applied numerals and indices, this watch demands attention and deserves it. It's a statement piece, a conversation starter, an object that inspires awe in watch geeks and the uninitiated alike. If the goal was to craft an enduring testament to IWC's mastery of watchmaking, I'd say they've wildly succeeded.