In the world of watchmaking, you will often hear the term "complication." While it might sound like a problem, it actually refers to something desirable. A complication is any function on a watch that does something other than tell the hours, minutes, and seconds.
Complications can range from the very common and useful to the incredibly complex and rare. They are a showcase of a brand's technical skill and a key part of what makes the world of watches so fascinating. This guide will cover the most popular complications you are likely to encounter.
The most common and useful complications
These are the complications you will find on the majority of watches. They add practical, everyday functionality to a standard timepiece.
The date complication
This is the most common complication of all. It displays the current date of the month, usually in a small window or aperture on the dial. A simple date complication uses a numbered disc underneath the dial that advances once every 24 hours. More advanced versions include the "Big Date," which uses two separate discs to display the date in large, easy-to-read numerals, and the "Day-Date," which also shows the day of the week.
The chronograph
A chronograph is a stopwatch function that is built into the watch, allowing you to time events without interfering with the regular timekeeping. It is typically operated by two pushers on the side of the case: one to start and stop the timing, and another to reset it to zero. The elapsed time is read via a long central seconds hand and smaller sub-dials on the main dial, which are used to track the timed minutes and hours.
The GMT (or dual time) complication
A GMT function allows a watch to display a second time zone. This is an incredibly useful feature for travelers, pilots, or anyone who frequently communicates with people in different parts of the world. It works by featuring a fourth, central hand that circles the dial once every 24 hours. This hand points to a 24-hour scale, often printed on the bezel, to indicate the time in a second location, which is often referred to as "home time."
Advanced and impressive complications
This next level of complications requires a much higher degree of mechanical complexity and is a hallmark of fine watchmaking.
The annual calendar
An annual calendar is a "smart" date function. It is a mechanical calendar that automatically accounts for the different lengths of the months, recognizing whether a month has 30 or 31 days. This means it only needs to be manually corrected once a year, on March 1st.
The perpetual calendar (or "QP")
A perpetual calendar is the next step up from an annual calendar. It is a highly complex mechanical calendar that knows the length of every month, including automatically accounting for the 29 days of February during a leap year. In theory, a perpetual calendar watch will not need to be manually adjusted until the year 2100, which is an exception in the Gregorian calendar (it is a century year not divisible by 400, and therefore not a leap year).
The moonphase
A moonphase is a beautiful, highly visual complication that displays the current phase of the moon as you would see it in the sky. It is displayed through a small aperture on the dial, which reveals a rotating disc with two moons painted on it. The disc completes a full cycle approximately every 29.5 days, accurately tracking the lunar cycle from new moon to full moon and back again.
The power reserve indicator
This is a very practical complication for mechanical watches, especially manual-wind models. It is a small gauge or hand on the dial that shows how much energy is left stored in the mainspring. It functions just like a fuel gauge for your car, letting you know when it is time to wind your watch before it stops running.
The "Grand Complications": The pinnacle of watchmaking
While the term can be debated, a "Grand Complication" generally refers to a watch that combines several highly complex features, often including a perpetual calendar, a chronograph, and a minute repeater. Two of the most revered and complex complications are:
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Tourbillon: This is a mesmerizing feature where the watch's escapement and balance wheel are placed in a rotating cage. The entire assembly rotates on its own axis, typically once per minute, in order to average out and counteract the negative effects of gravity on the movement's accuracy.
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Minute Repeater: This is a complication that chimes the exact time on demand. By activating a slide on the side of the case, a complex system of tiny hammers strikes gongs inside the watch to sound out the hours, quarter-hours, and minutes.
Conclusion: From practical tools to works of art
Complications began as practical tools. The chronograph was for timing races, the GMT was for pilots, and the date was for everyday convenience. Today, while many of these functions remain incredibly useful, the more complex complications are celebrated as incredible demonstrations of mechanical artistry and human ingenuity. Understanding what they are and how they work adds a new and fascinating layer of appreciation for the tiny, living machine on your wrist.