Feature: Happy 150th Birthday, IWC

A whopping century-and-a-half has passed since Boston-born engineer Florentine Ariosto Jones frightened the life out of Swiss watchmakers by introducing modern mass production to the banks of the River Rhine. Established as far away as possible from the peeved Swiss watchmaking hub, in the German-surrounded nodule of Schaffhausen IWC has steadfastly contributed its logical, engineer's perspective to the art of Swiss watchmaking for the last 150 years. And what better way to celebrate than with a trio of the finest watches IWC makes?

The Big Pilot Perpetual Calendar

While it's particularly unimpressive for a piece of modern technology to know what the date it is, the ability of a mechanical watch to keep track of every single one of the 29,930 days between now and the year 2100 is astounding. Because it's not as simple as defining the length of a day, month and year—there are four variants of month and two variants of year, for example—a perpetual calendar ends up being a very complicated beast indeed.

But how did we end up in this mess? Why can't time be nice and neat? As with many things, the modern calendar can be traced back to the Romans, who used the passage of the moon to determine the periods of the year. Oddly, only ten months of 30 and 31 days were recorded, with a period of 51 days through the winter left unaccounted for.

The IWC Big Pilot Perpetual Chronograph IW502620 is an impressive feat of engineering

This was reformed by Julius Caesar in 46 BC, by shoe-horning a further two months to fill all 365 days of the year—naturally, he named one after himself. The year of the swap between calendars ended up having 445 days for the recalibration, and was aptly named the 'year of confusion'.

But a solar year has 365-and-a-quarter days, not 365; thankfully, Caeser was on the ball. An extra day was added every four years—that's the leap year. Unfortunately, while this came close, it still wasn't perfect, because—more accurately speaking—a solar year is actually 365.2425 days long.

This 0.002% difference was corrected by Pope Gregory the 13th, who suggested that the leap year be dropped once every century for three centuries out of four. 2000 was one of those years where the leap year continued as normal, however the leap year in 2100 will be ignored. This is why mechanical perpetual calendars are only accurate to the year 2100.

The crown is used to do all the adjustment—usually multiple pushers are required

As well as the ability to track this befuddling array of dates—which we'll cover in more detail in a future video—there's something particularly special about the IWC perpetual calendar. While on most calendar watches, you'll see an array of hidden pushers circling the case, the IWC has none.

That's because in 1985, IWC watchmaker Kurt Klaus announced the creation of a movement that could be set just by the crown. Built around a programme wheel that uses different length teeth to determine the duration of each month over a four-year period, a simple turn of the crown will advance every function forward correctly. A word of warning to prospective owners however—the calendar doesn't go backwards, only forwards. If you go too far, you've got to wait for time to catch up with it.

The Portuguese Tourbillon

While the tourbillon is a Breguet invention, it sits well at home with IWC's mentality for over-engineering. The Portuguese itself was created as a wristwatch with the precision of a marine chronometer—the large pocket watch movement used gave the Portuguese its famously broad case—and a tourbillon goes a step further in that pursuit for accuracy.

There are many things that can cause a movement to lose accuracy, such as the temperature of the watch or the amplitude of the mainspring as it winds down—but the factor we're interested in here is position. A watch, for obvious reasons, needs to remain accurate whichever way it's held, and an important dynamic in achieving this is the balance of—unsurprisingly—the balance wheel.

A balance wheel is the part of the movement that provides the beat for the hands to march to, a compact version of the swinging pendulum in a clock. It bounces back and forth with the help of a fine coiled spring, pausing the running of the mechanism between each swing. This gives a mechanical watch its tell-tale high-speed tick.

The IWC Portuguese Tourbillon IW504207 demonstrates the beauty and precision of a tourbillon

The balance—or 'poise'—of a balance wheel is typically accomplished by the addition or removal of weight from its perimeter. Weight added is often done with strategically placed screws, while weight removed is carved from the balance wheel itself.

But this can only work so well, particularly with the emphasis of certain positions on an imbalance. A pocket watch, for example, hangs in the vertical position all day long, balance wheel fighting against gravity. The smallest imbalance can be accentuated enough to cause a significant deviation in accuracy when considering something like a marine chronometer.

So, the tourbillon was developed. By encapsulating the entire balance and rotating it continuously, any positional error caused by imperfect poise can be averaged out over the course of a full rotation. A consistent beat is the result, and a watch that keeps accurate time no matter which way round it is.

By averaging the imbalance in the balance wheel, the tourbillon increases positional accuracy

The Portuguese Minute Repeater

There are a number of theories surrounding the origins of the minute repeater watch. Able to sing a chime on command that, as well as sounding pleasant, tells the time in hours, quarters and minutes, a minute repeater is one of the most coveted complications in all of watchmaking.

The first minute repeaters were to be found in clocks as early as the 17th century, suggesting the use as a practical one and not simply a novelty. While some suggest the operation was intended for the blind, the most common understanding is this: with no electricity and long, winter nights, it could be difficult to read the small dials of period clocks, and so a chime enabled the users to clearly discern the time. Makes sense.

The most impressive complication of them all: the IWC Portuguese Minute Repeater IW524205

Simply pull the slide lever of the minute repeater and the time is told like so: the low note for the hours, alternating high and low notes for the quarters, and high notes for the minutes. As the minute repeater uses a large amount of a power, a separate mainspring is wound as the slide is pulled. But how does the mechanism know what the time is?

There's a reason the minute repeater is so revered amongst watchmakers—few complications are more involved. Individual snail cams—one for the hours, one for the quarters and one for the minutes—turn with their corresponding hands. Each cam is stepped for the maximum number of chimes it can have, so that's 12 for the hours, four for the quarters and 14 for the minutes.

Pull the slide and the hours, quarters and minutes are chimed for you

When the mechanism is wound by the slide, lever-like components called racks pivot onto the cams, limited in their travel by the cams' steps. When the slide is released, the racks are withdrawn one by one, teeth along their edges triggering the chimes. The deeper the step on the cam, the more chimes the repeater will give, corresponding with the time shown by the watch.

This is a hugely simplified explanation for a device that takes watchmakers around 300 hours to complete. It may not be the most visually impressive complication, but it's the most special, and a fitting end to our celebration of IWC's 150 years.

Happy birthday, IWC.

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