IWC is Thinking Very Far Ahead with their New Portugieser Eternal Calendar

Watches that do more than a human being is capable of are nothing new. Rolex, Omega, and others make dive watches that are capable of reaching depths that no man or woman could survive. The Rolex Deepsea Challenge is rated to 11,000 meters (which means it’s tested to even greater depths) while the deepest point in the ocean is about 10,900 meters, give or take. That means this particular dive watch can go deeper than any depth possible on the planet. Even that, somehow, feels more practical than IWC’s big release at Watches & Wonders, the Portugieser Eternal Calendar. This is the brand’s first secular calendar, which accounts for leap-year exception rules in the Gregorian calendar that play out over a 400 year span. A calendar complication that no living human will have a chance to observe do its thing in real time is one thing, but it’s the moonphase on this watch that is truly looking ahead: IWC claims it’s accurate to 45 million years. And just think, it wasn’t even ten years ago that the Apple Watch had many in this industry scared that watchmaking could be killed by smart-gadgets. Talk about confidence. 

The concept of a secular calendar will be worth a refresher for many, as it’s a truly rare complication that most brands simply don’t attempt given the incredibly long timeframes involved (the last one we discussed in these pages was from indie Furlan Marri). The gist is this: in addition to a leap year every four years, Gregorian calendar needs an additional tweak to keep it in line with a solar year. To do this, certain leap years are skipped. Any centurial year divisible by 400 is a leap year, while others are “common” years, meaning they have 28 day Februaries. In practice, this means that the years 2000 and 2400 are leap years, while 2100, 2200, and 2300 are common years. A secular calendar, effectively, knows the difference between leap and common years at these staggering centuries long intervals, and does not need a correction in a skipped leap year like a run of the mill perpetual calendar would. 


The Portugieser Eternal Calendar accomplishes this through a movement designed with the same basic architecture as IWC’s existing perpetual calendar movements, but adds a so-called 400-years gear module that completes a rotation once every 400 years, and is made of only eight additional parts. Like every other IWC perpetual calendar, everything is still controlled via the crown. IWC claims the new automatic caliber (which has been given the number 52640 and has seven day power reserve) will calculate the leap year correctly until 3999, and they remind us that it hasn’t been officially determined if the year 4000 will be a leap year or not. Something for the grandkids to work out, I suppose. 

And then there’s the moon phase, a complication that is traditionally incorporated into many classic perpetual calendar movements, but isn’t technically required. It’s a classical bonus, though, and is very much a part of IWC’s perpetual calendar history. The key to making a perpetually accurate moon phase is to gear a lunar cycle as closely as possible to a calendar month, and IWC has done this with a special “reduction gear” between the base movement and moon phase disc, as well as new technology that allows IWC engineers to simulate trillions of potential permutations in the number of teeth used in these gears, as well as their size and proportion to one another. It’s effectively a very complex math problem, but the end result is a moon phase that will require precisely one correction in a 45 million year period. This is a watch that you’ll probably want to have on a winder. 

OK, let’s talk about the watch itself. It’s a platinum, in a case measuring 44.4mm in diameter and 15mm tall in a familiar Portugieser profile. The dial is glass and construction is quite complex, with the underside being given a frosted finish that then has a white lacquer applied to it. The subdials that display the calendar functions are separate pieces that are machined and finished independently before being applied to the dial. Printed elements are then applied, and because of the depth of the glass, each of these elements take on a complex depth, and are meant to appear as if they are floating on the dial’s surface. 

There’s something delightfully insane about a watch like this that no living person will ever witness perform the function it was designed for. This is obviously a very niche product and has a retail price, we presume, that reflects this (it’s in the rarefied “inquire for pricing” category that generally means if you have to ask, well, you know the rest). That said, there are other new members of the Portugieser collection that have been announced alongside the Eternal Calendar (stories on those to come later this week) that are a bit more accessible. IWC

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Zach is a native of New Hampshire, and he has been interested in watches since the age of 13, when he walked into Macy’s and bought a gaudy, quartz, two-tone Citizen chronograph with his hard earned Bar Mitzvah money. It was lost in a move years ago, but he continues to hunt for a similar piece on eBay. Zach loves a wide variety of watches, but leans toward classic designs and proportions that have stood the test of time. He is currently obsessed with Grand Seiko.