Rolex Watchmaking Training Center
Getting Complicated
Watchmaking 101

Getting Complicated

One of the most peculiar but important terms in watchmaking is “complication.” The word carries all sorts of natural baggage with it in English, but in horology it simply refers to any feature or indicator on a watch other than the hours, minutes, and seconds. Showing the date at the three o’clock position? That’s a complication. A chronograph? That’s also a complication.

The Date

While there are a nearly infinite array of complications out there, from the simple to the fanciful, Rolex watches tend to be more practically oriented, with useful complications that bring value to customers on a daily basis. This is an introduction to many of watchmaking’s most important complications as seen through Rolex watches:

The Date

The Date

One of the most popular complications, a date display shows the wearer the day of the month in a simple, legible manner. Rolex first introduced the Datejust in 1945 to celebrate the company’s 40th anniversary and the watch has been in continuous production ever since. It uses a numbered wheel to show the date at three o’clock and, on contemporary calibers, the date switches instantaneously and can be adjusted in either direction, both of which were key innovations of the 20th century.

The Day-Date

Stepping to the next level of complication, Rolex’s signature combination of the day of the week and date displays is the namesake for the iconic Day-Date watch. When it debuted in 1956, the Day-Date was the first watch to both show the date and spell out the day of the week, offering a new and very practical type of calendar watch.

The Annual Calendar

Both date and day-date complications require resetting at the end of any month not ending in 31 days, as there are 31 possible positions for the date wheel. However, an annual calendar is a special mechanism that only needs to be reset once per year, at the end of February. It can automatically account for the months with 30 and 31 days. The Rolex Sky-Dweller is a unique kind of annual calendar that can be set with the assistance of the patented Ring Command bezel system.

The Annual Calendar


There are many different versions of the GMT or travel-time complication, but they are all united by the concept of tracking the time in a second timezone without disrupting the time display for the so-called “home time.” The Rolex GMT-Master was the first watch to do this with the assistance of an additional 24-hour hand on the dial and a rotating bezel, and today’s GMT-Master II combines this with the ability to independently set the watch’s hour hand, allowing it to track up to three timezones at once, all with only one extra hand.

The Chronograph

A favorite of watchmakers and collectors alike, the chronograph has a special position of respect and excitement in the horological pantheon. It essentially adds a stopwatch function to a wristwatch, allowing the wearer to start, stop, and reset a second timekeeping function to track the elapsed time of any activity. Many of the best-known chronographs have their origins in motorsport, including the vaunted Rolex Daytona. Its ability to time events up to 12 hours and its tachymeter bezel make it purpose-built for the track.

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