In this article, we cover what a watch complication is, its relationship to subdials, then we lay out a guide to every watch complication.
In the past ten years or so, there’s one thing the top selling watches at auction have in common. They’re all decked out with complications.
Suffice to say, watch lovers love complications. If you’re looking to learn more about these feats of horology, you’re in the right place.
What is a Watch Complication?
A watch complication is any function on your timepiece other than the time-telling one. The first ever wristwatch complication was the date window, introduced by a Swiss watchmaker called Hammerly in 1915.
Complications can be simple or so intricate that it takes master-level specialty skills to build them.
They also range from rare and highly-coveted to so common that we take them for granted.
In fact, Rolex’s Submariner Date tends to be mistaken as the standard version, with people often calling the regular Sub the “Submariner No-Date”.
Several complications call for subdials, or smaller dials on the dial face. Some of these include chronographs, one of the most common complications, power reserves, moonphases, and other time zones.
Subdials are also referred to as auxiliary dials. Now that we’re caught up, let’s get to it.
List of Watch Complications
Here are the watch complications you should know…
As you can guess, a date complication displays today’s date. We mentioned that they first appeared on wristwatches in 1915, but pocket watches have been using dates as far back as the 1800s.
The date complication takes several forms.
This format is a literal window located anywhere on the dial, though it’s usually on, near, or over the 3 hour marker. If the numbers alternate between red and black, that’s called a “Casino” date.
Rolex often puts a magnifying glass, or a “Cyclops lens”, over the aperture, making it equally as legible as our next date variation.
The big date is much larger than a regular aperture, and often has two windows, one for the tens digit and one for the ones digit.
It’s also usually on the top of the dial like with the Zeppelin Big Date Los Angeles, but this isn’t a rule.
Also known as a subsidiary date, the date appears in a small subdial featuring sub-indices, one through 31.
It’s not the most legible format, but it definitely adds a whimsical touch as it does with this Audemars piguet Royal Oak.
This format is often called a pointers date as well. The dates are listed along the edge or outer periphery of the dial.
An extra long date hand points to today’s date, and it comes out from the center along with the minute and hour hands.
The date hand on this Oris Big Crown is equipped with a red half-frame instead of an arrow to distinguish it from the time-telling hands.
The day-date is just like the date complication, but with the day of the week added. The day and date can be side by side, like in this Timex Easy Reader.
The day can also be placed in a completely separate part of the dial, often so the whole proper name can be spelled out, which is great for legibility.
Taking the next evolutionary step from the Day-Date, Calendar complications add the month and sometimes even the year.
Also called a “complete calendar,” the triple calendar features the current month, in addition to the day and date.
This complication is the same as a triple calendar, except the annual calendar also displays the current year. It doesn’t account for leap years though.
Again, it’s just like an annual calendar, only this time, the perpetual does indeed know when it’s a leap year.
The Tissot Tradition Perpetual Calendar features the day, date, month, year, and accounts for leap years.
EOT stands for equation of time, and it features the day, date, month, year, and it measures the difference between the standard time we live by, and actual solar time, which is the time according to the actual position of the sun.
This PANERAI Luminor 1950 Equation of Time watch measures the difference in minutes, which is usually how it’s done.
Not the most practical of complications, but it’s horologically exquisite and a neat party trick.
Dual Time Zone Complications
Also known as travel complications, dual time zone features tell you the time in one or more other time zones in addition to your own.
While some consider a dual movement feature to be a complication, it’s actually just two movements within the same case.
These are the dual time zone complications.
Using the same movement, a dual time complication displays two time zones at the same time.
With older GMT (Greenwich Mean Time) watches, the much longer GMT hand pointed to the numbers on the bezel, indicating a second time zone.
The 2.0 version of this complication is a GMT hand that’s independent of the hour hand.
What this means is that, if the watch comes with a rotating bezel, you can check three time zones: The time that your regular hour and minute hands are pointing to, Greenwich Mean Time, and whatever time zone you set the rotating bezel to.
The most famous GMT watch is the Rolex GMT Master II, considered the jetsetter’s weapon of choice.
Fixed Hour Hand GMT
A GMT complication with a fixed hour hand is made specifically for pilots and features an additional hour hand. It makes one revolution per day.
This means that when it’s pointing at the 6 o’clock index, it’s referring to noon. When it points to 12, it’s midnight.
World Time Zone
The World Time Zone usually has an inner bezel with military time and an outer bezel indicating a major city for each of the 24 time zones.
This Citizen Eco-Drive World Time is radio-controlled and features two tracks of major cities for legibility.
Very simply put, a chronograph is a regular time-telling watch with stopwatch capabilities. They range in complexity and are one of the most common complications.
Both of these are the common three subdial chronographs we’re most familiar with. They’re equipped with a stopwatch hand, also known as the sweeping second hand.
When this hand is activated, one subdial will track elapsed minutes, while the other tracks elapsed hours. The third subdial features the running seconds for the time-telling.
One-Button Mono-Poussier Chronograph
A monopusher features one button that you’ll push consecutively to start, reset, and stop the stopwatch function. Unlike it’s multi-button cousins, the mono-poussier can’t measure interrupted time spans.
The Fly-back was made for pilots, though it can prove useful to any job that requires hyper precise measurement of time spans at a second’s notice. Once the second button is pushed, all the counters reset and go straight to zero.
The Rattrapante chronograph usually has three pushers and two second hands. This way, the user can measure two spans of time separately.
Since they’re often used for racing, chronographs generally come with a tachymeter scale. Both the Speedy and the Lunar Pilot are good examples.
It’s used to measure speed traveled over a period of time, usually miles or kilometers per hour. You’ll typically find the scale on the outer or inner bezel.
Power Reserve Indicator
The Power Reserve Indicator displays the watch’s remaining power, and gets its measurement via tension from the mainspring.
In the Seiko Presage Cocktail Time, the power reserve is a subdial measuring hours remaining.
The Tourbillon doesn’t actually add function, but improves them. As such, people often argue if it’s a complication at all.
The tourbillon is an elaborate cage that spirals the balance wheel on its own axis. This enhances balance and protects the watch from gravity and movement, vastly improving its accuracy.
Since mechanical watches aren’t necessarily coveted for their accuracy these days, tourbillons are more admired for their craft, and are a great visual addition to skeletonized dials.
This Agelocer Hollow Tourbillon watch for example is hollow on both sides, so you can see the tourbillon at work.
Originally built for sailors to gauge tides, a moonphase displays the phases of the moon, full, half, quarter, or new. Like the tourbillon, it’s appreciated more for its aesthetic quality, and often used in dress watches.
It certainly adds a tone of whimsy to the iconic Orient Sun and Moon watch.
Jump Hour Complication
The jump hour is a window that displays the hour of the day. Naturally, it changes every 60 minutes. It’s like a visual grandfather clock chime, or a manual digital clock, if there’s a separate window for the minutes.
The Stauer Dashtronic is based on a 1930 design and is a unique take on the jump hour complication, making the watch look a bit like a weight scale.
When a lever on the side of the case is pulled, a minute repeater chimes out the current time. It’s like an old school version of when you ask Alexa what time it is.
Nothing complex here, an alarm is a complication that will notify you of a preset specific point in time.
A lot of complications are obviously obsolete, but mechanical watches are mostly obsolete too, at least functionally. Watches are relevant because of their style, the story they tell, and the engineering and art behind them.
Their time-telling function is like a necessary bonus. This is the same with complications. Check out Reference 57260 from Vacheron Constantin and tell me that its 57-complication status isn’t compelling.