Horological complications: a beginner’s guide

Know-how Watches

Written by Julie de Los Rios - Tuesday, February 27, 2024

We've already covered watch movements, which you now master perfectly!

Over time and with the acquisition of new pieces, the watch becomes much more than just a timepiece or a stylish accessory. As they gain confidence and accumulate technical knowledge, collectors will naturally gravitate towards models with complications. Complications are, of course, primarily associated with mechanical watches.

Isn't a mechanical watch already a complex object in itself? "Certainly not," watchmakers will retort from behind their workbenches. With their focus on the infinitely small, these "mad scientists" continuously push boundaries. Because, beyond its aesthetic and practical qualities, a timepiece is first and foremost a technical feat.

Designing a watch that tells time through a mechanical movement – meaning it operates without a battery, either through a manually wound calibre or the movements of the wearer for an automatic model – is already a challenging task. As if that weren't enough, watchmakers have conceived all sorts of complications.

But what exactly is a complication? It's a function other than simply displaying the hour and minute. Let whoever has never nodded along without truly understanding how a tourbillon works raise their hand...

Highly coveted, watches with complications are equipped with modules added to the movement – i.e. additional specific mechanisms. And in this pursuit, the Holy Grail for both the watchmaker and the collector remains the Grande Complication, which must include, at a minimum, a minute repeater, a split-seconds chronograph, and a perpetual calendar.

The top manufactures showcase their craftsmanship by presenting masterpieces that offer a multitude of functions. Take, for example, Vacheron Constantin or Patek Philippe, which excel in the field with pocket watches that can feature over 50 complications. Pretty impressive!

These complications can be technical, practical, astronomical, playful, or even enhance the watch's precision. Here’s an overview of the main complications, categorized by family. You'll become an expert in no time!

I. Day Date Display

Date Display

Knowing the date and day – this is a very useful complication. If you encounter the French term “quantième”, it refers to a date display, which is the most common function.

How does it work? Typically, it involves a disc positioned on the periphery of the movement, marked with numbers from 1 to 31. Each day, at midnight, the disc moves forward. Through a window—often located at 3 or 6 o'clock on the dial, sometimes intricately designed—you can then see the current date.

In addition to date displays, some watches feature another disc that indicates the days of the week, from Monday to Sunday.

Large Date

There are a few variations within this category. For instance, we refer to it as "Large Date" when two independent discs display the two digits of the date. This allows for a centred and larger display, making it easier to read.

Annual Calendar

The annual calendar is a complication that adds the month to the date. Technically, the mechanism considers the lengths of the months (30 or 31 days). However, it's important to note that the annual calendar doesn't automatically adjust for the duration of February (28 or 29 days). Therefore, the watch will need to be adjusted once a year, on March 1st.

Perpetual Calendar

Lastly, the perpetual calendar, highly valued by connoisseurs, is a more sophisticated version as it includes a count for 4 years and thus accommodates leap years. In this case, the date only needs to be adjusted for skipped leap years, which occurs three times every 400 years!

Breguet Classique 7327 – Perpetual Calendar © Breguet

II. Dual Time

GMT or UTC Complication

This is an incredibly convenient complication for globetrotters or businesswomen who travel the world. Known as GMT (which stands for Greenwich Mean Time) or UTC (Coordinated Universal Time), this complication allows for displaying the time in a second time zone, enabling the wearer to know both the local time and the time back home.

This complication often appears as an additional hand—distinguishable by its colour or shape—on the dial. Unlike the hour hand, this one completes one rotation every 24 hours, making it half as fast. To determine the GMT time, the wearer often consults a 24-hour graduated bezel.

If you’re in New York for a business trip, this function allows you to know, for instance, the time in France without having to mentally add 6 hours.

But how does it work? Once you've reached your destination, simply set the GMT hand to the time of your home country and the hour hand to the local time. To further simplify things, manufacturers like Rolex, with its GMT Master, have created two-tone bezels that allow users to differentiate between day and night hours—knowing whether it's 6 am or pm. Incredibly practical! You never know, especially with jet lag!

Many GMT watches now feature a separate GMT hand detached from the hour hand, allowing for independent adjustment of both hands or simultaneous adjustment of the minute hand and GMT hand.

Rolex Oyster Perpetual GMT-Master II © Rolex

World Timer

Even more intricate and complex, the Worldtimer allows you to know the time in all major time zones at a glance. This complication is recognisable by its outer disc listing reference cities for 24 time zones (or more). This ring rotates via crown adjustment or a pusher.

How does it work? Simply set your local time zone at noon to define the positions of other reference cities based on the local time zone. On the second ring, marked from 1 to 24 hours, the exact time for each zone will be indicated. To know the time in cities like London or New York, for example, just check the time opposite the chosen city. To impress everyone at your next party, mention that Swiss watchmaker Louis Cottier introduced the first universal timepiece in 1930, during the early days of aviation.

III. “Sonnerie” (chiming mechanism)

“Petite Sonnerie” and “Grande Sonnerie”

There are different versions of chiming watches. The “petite sonnerie” strikes the quarters without repeating the hours, while the “grande sonnerie” strikes the quarters and repeats the hours. This complication is certainly useful to not forget the time but somewhat anxiety-inducing... It makes us aware of how quickly or slowly time passes... It’s a matter of perspective!

Minute Repeater

The minute repeater, also known as the Queen of Complications, chimes the time upon request. It was invented to know the time in the dark. Indeed, by activating the pusher, often positioned between 7 and 9 o'clock, the mechanism will produce a sound for the hours, one for the quarters, and a last one for the minutes. The tones are different, either deeper or sharper to assist the wearer of the watch. To understand it well, you will need to adopt a new logic. Once mastered, this playful complication will fascinate you.

The alarm function allows you to set a ring for a specific time.

Audemars Piguet Royal Oak Minute Repeater “Supersonnerie” © Audemars Piguet Chopard L.U.C Strike One © Chopard

IV. Chronograph

The chronograph is a classic in watch collections, offering a sporty aesthetic while enabling the measurement of time intervals, from seconds to minutes, hours, and sometimes even fractions of a second like quarters, tenths, or thousandths. But what sets it apart from a chronometer? A chronometer is a chronograph that has successfully undergone various reliability, precision, and resistance tests administered by the Official Swiss Chronometer Testing Institute.

There are several variations of the chronograph. The flyback chronograph, for example, allows for the initiation of a new timing session while one is already in progress, activated by a single pusher. On the other hand, the split-seconds chronograph (or "rattrapante") features a second hand that can measure intermediate times before "catching up" instantly with the main chronograph hand.

Zenith Chronomaster Original © Zenith

V. Power Reserve

The power reserve complication is highly beneficial for those who wear automatic or manual winding mechanical watches. It indicates the watch's autonomy and thus the remaining operating duration before needing to be wound. Often displayed as a gauge, it can range from 36 hours to around fifty days.

Frédérique Constant Classic Power Reserve Big Date Manufacture © Frédérique Constant

VI. Tourbillon

The tourbillon is designed to enhance the accuracy of a watch by compensating for the influences of gravitational pull on the watch movement. Originating from an idea by Abraham Louis Breguet in 1801— to enable the balance wheel to oscillate 360° rather than just vertically —the tourbillon is a small cage containing the balance wheel, the spring, and the escapement, which rotates on itself and completes a full rotation in one minute.

Since then, watchmakers have continuously embraced and reinvented it: inclined at 30 degrees at the end of the 20th century for improved efficiency, triaxial like Jaeger-LeCoultre's Gyrotourbillon, thus lighter and more aerial... Beyond its technical aspect, it offers a captivating spectacle on the dial. It can also serve an aesthetic function, with houses adorning it with various motifs. Chanel, for example, adorns it with diamonds, comets, or camellias — signature codes dear to Mademoiselle Chanel.

Chanel J12 Diamond Tourbillon (Calibre 5) © Chanel Jaeger-LeCoultre Reverso Gyrotourbillon © Jaeger-LeCoultre

VII. Conceptual Complications

Retrograde

These complications do not provide additional information but rather redefine how time is read. This includes a display other than the simple three hands for hours, minutes, and seconds. Among them is the retrograde, a trend spotted at Watches & Wonders 2023.

"A display is said to be retrograde when it does not complete a full rotation of the dial but returns to its starting point (instantaneously) to begin a new cycle after covering its entire measuring segment. Typically, this is represented by an arc traversed by a hand", as stated on Vacheron Constantin's website – the brand being known for retrograde display.

Vacheron Constantin Patrimony retrograde day-date © Vacheron Constantin

Jumping Hours and Minutes

Continuing in the spirit of approaching time playfully, jumping hours or minutes involve the sudden jump of the hand or digital display when transitioning to the next hour or minute. This facilitates reading by avoiding the obstruction of a part of the numeral.

Patek Philippe Chiming Jump Hour 5275 © Patek Philippe

Mysterious Hour

Finally, the mysterious hour, notably found in Cartier watches, is a purely aesthetic complication. The hands, apparently unattached to any axis, seem to float on the dial. This effect is achieved through the use of transparent discs driven from the exterior.

Cartier Heure Extraordinaire © Bérengère Treussard

VIII. Astronomical Complications

Inspired by astronomical clocks, one of the finest specimens of which can be found in Prague, these complications are a marvel to behold. They display local time, old Czech hours, diurnal solar time, the position of the sun and moon in the sky, the lunar phase, the zodiac sign and decan currently in effect, sidereal time, and even feature automatons that activate at fixed times.

Moon Phase

When it comes to watches, the most common astronomical complication is the indication of the moon phase, represented by a disc partially hidden under the dial. Driven by a toothed wheel, it advances one notch each day, allowing one to monitor the moon's progression. While it may serve surfers who watch for tide movements — themselves influenced by the moon — it is more poetic than practical for daily use. Sometimes, it is embodied by a 3D sphere.

Equation of Time

Other, much rarer astronomical complications exist. These include indicating the sunrise and sunset or moonrise and moonset, the tidal coefficient, and the equation of time — Panerai, Breguet, Blancpain, and Audemars Piguet have presented such complications. The equation of time displays the difference between "true" solar time (that of nature) and mean solar time (that of our civilization, conventionally 24 hours in duration).

Finally, the sky map reveals the configuration of the sky with the movement of the stars, the position of the moon, and its phases during its cycle. While these complications may not be very useful in our urban lives, they represent the pinnacle of craftsmanship for watch manufactures.

You're now ready to impress everyone with your sharp knowledge of watches. You'll never look at watches the same way again, that's for sure! Date, tourbillon, moon phase, or minute repeater now hold no secrets for you. But which of these complications captivates you the most?