How often do you set your watch? Your answer likely depends on how much you wear it. If you only use it occasionally, it’s likely you set it each time you pick it up. But if you sport the same watch daily (or keep it on a winder when not in use), you probably only adjust it when you notice a deviation. Annual calendar and perpetual calendar watches have made this task easier, but unless you’ve sworn off everything save for digital pieces, setting the time is a fact of watch ownership. And as collectors of vintage watches with no quick-set date can attest, laboriously spinning forward the hands just to get the date window correct can make even the most hardened aficionado weep. So, we were understandably interested when IWC announced its new Eternal Calendar is accurate for 45 million years. Well, the moon phase is, at least. The perpetual calendar complication? Your fiftieth great-grandchild might have to adjust once in the year 4000. Still, the new IWC Portugieser Eternal Calendar watch is a remarkable achievement in watch movement design, and we saw it hands-on at Watches & Wonders 2024.
This mind-boggling capability has more to do with super-computing than the automatic mechanical movement might suggest. By using software to simulate trillions of gearing combinations, IWC was able to identify a sequence that would provide the right system of timekeeping to enable the Eternal’s long-lasting accuracy. Of course, such breakthroughs in horology ought to be paired with equally noticeable aesthetics and on the dial, they certainly are. While the arrangement of IWC perpetual calendar dials have always been captivating for both their symmetry as well as simplicity, the Eternal tweaks this approach, removing the seconds-track from the subdial at 9 o’clock, and updating the double-moonphase indication. Here, an understandably braggadocious label helps solve the cut-off numeral problem, replacing the chopped “12” with an “Eternal Calendar” branding. Left and right of the moonphase, the hemisphere indicators have also been simplified by the removal of the “N” and “S” labels, instead relying on intuitively shaped semi-circles to tell which part of the moonphase corresponds to the northern and southern hemispheres. Color has also been deleted, with the seven-day power reserve taking on a monochrome look that matches the dial’s overall appearance. All these updates connect in their own way to the biggest part of the Portugieser calendar’s refresh — the glass/lacquer construction that makes the dial text appear to be floating. Starting with a thick glass dial, IWC has coated the underside with white lacquer, then printed the text and applied the silver numerals on top. When paired with other dimensional elements like the hands, separate double-moonphase indicator, and a stepped cut-out at 4 o’clock, the Eternal’s dial takes on a depth that gives it an unmistakable character.
IWC’s Caliber 52640 automatic movement is the engine behind all this wizardry, and it’s on full display on the Eternal’s reverse side. Using a panoramic sapphire caseback used elsewhere in the new Portugieser lineup, the inner workings can be clearly seen edge-to-edge. Those who occupy their spare time staring at watch movements will be able to quickly tell this is not your typical engine thanks to the unique gear layout toward the top of the caliber. And while it cannot be seen from the back, hidden inside the hard-working stack of metal is the 52640’s “400-year gear”, which (as the name suggests) rotates once every four centuries in order to correctly account for the years 2100, 2200, and 2300. These years, while they occur on the normal four-year leap year cycle, are not actually leap years, and if you find that confusing, imagine trying to make a watch movement that accounts for these irregularities. It’s these quirks that ultimately limit the Eternal Calendar’s functionality, although using the word “limit” to describe a watch that can theoretically keep time for twice as long as the entire anno domini period seems unfair. Nonetheless, these irregularities stack up and, sadly, mean the watch will need correction in the year 4000. Ironically, an easier task for the Caliber 52640 is the correct operation of the moonphase. Here, the moon’s 29.5 day schedule is so predictable, the Eternal can account for it until the year 45002024. That is not a typo. Amusingly, IWC has elected to advertise not the 45 million year moonphase on the movement’s rotor, but the seven-day power reserve.
At 15mm thick, the new Eternal Calendar is not significantly beefier than most other calendar watches, but the unique case design gives it a special depth and presence. Befitting such a powerful watch, its cased in platinum and offers a white lacquer flange built into the case. With numerals printed on the side and a clearly delineated minute track printed atop, it’s incorporated beneath the box-sapphire crystal and appears somehow raised. When viewed from the top, it frames the dial yet it’s hard to say where the dial ends and the flange begins. The appearance is almost (dare I say it?) like that of a smartwatch, albeit one from an alternate universe where the ubiquitous black pillowed rectangles were all suddenly turned circular and white. Arguably the most impressive aspect of the 44mm case is its absence of any buttons normally found on calendar watches. Instead, the Portugieser’s unguarded 3 o’clock crown is the sole mechanism for setting and correcting a generously enabled timepiece. The black alligator leather strap is affixed via the sloping lugs, and is paired with a folding clasp made of matching platinum.
Trite as it sounds, watches have a way of making us think about time. Held in the hand or worn on the wrist, the IWC Portugieser IW505701 stretches the scale from that of a typical calendar watch (days, months, years) to literal eons. By pushing forward the boundaries of watchmaking and creating a timepiece whose limitations (manufacturer recommended service intervals, aside) exist thousands and even millions of years in the future, the Eternal Calendar becomes an almost philosophical experiment like Zeno’s arrow or Theseus’ ship. Considering that the Eternal Calendar could theoretically run until it’s component parts literally erode into dust is a thought-provoking exercise. This is more significant in a time when the dirty secret of production — and yes, that includes watchmaking — is that it’s often cheaper to replace than to repair. At $155,000 USD, the IW505701 is anything but a disposable watch, but mainly because of it’s ability to at least pause the conversation around the technical limits of watchmaking. Realistically, a central lesson of horology is that there’s always another development gestating at the bench of some genius watchmaker so is this the be-all-end-all of calendar watches? Probably not. Yet while it may not be the “end of history”, the Eternal Calendar gets darn close. For more information on the IWC Portugieser Eternal Calendar, please visit the brand’s website.
