4 Common Watch Complications Explained

A watch used to be a piece of equipment that had one function and one function only: to tell the time. In 2018, watches include everything from perpetual calendars and moon phases to heart rate monitors and GPS tracking systems.

These additional functions, apart from the likes of the latter two which are features of the more-device-than-a-watch smartwatch, are known in horology as ‘complications’. Complications are anything other than the display of the time, for instance, the date, day and month of an annual calendar or a moon phase subdial.

But the world of watch complications is inevitably much more complicated than it first appears. Not only are there a vast number of different types and styles built for varying purposes, complications often serve simply as testament to the complexity of their mechanical assembly in themselves.

So, to get to grips with some of the more common watch complications, we’re going to break down six of them and explain exactly what they’re all about.


The crown for the most popular complication would likely go the tourbillon: a feature first produced to improve accuracy by negating the effects of gravity on the watch.

However, the tourbillon — french for ‘whirlwind’ — often recognised by its characteristic balance wheel housed in a cage that’s continuously moving in one direction, has been proven to be no more accurate than a traditional watch. And so today it appears in many different forms and functions, from second counters to multi-axis tourbillons. And due to being one of the most difficult movements to make by hand, it is synonymous with the most prestigious timepieces.

Minute Repeater

A complication that traces its roots back to the days of pocket watches, the minute repeater is one the oldest and most complex features that still turns up in watches today.

Known by its hallmark chime, the minute repeater allowed wearers to tell the time in the dark; chiming first for the hour, then the quarters, then the minutes, if any. Although largely redundant today, the minute repeater has stood the test of time for good reason and is seen as a symbol of high-end watchmaking.

Perpetual Calendar

A highly complex and functional complication, the perpetual calendar is one of the most desirable and romantic features you can have in a watch. Dating back over a thousand years, the perpetual calendar offers an accurate way to track the date over many years, needing adjustment only once every century.

Thanks to its multitude of gears that turn anywhere from several times a second to once every four years or more, you can track the day, month, year, leap year, and even the century and millennium. Depending on the watch and brand, it can appear in apertures or subdials and will almost always cost you a small fortune.

Moon Phase

A love/hate complication is there ever was one, the moon phase is considered by some as a frivolous feature that has no practical use in a watch today. But say what they will, there a few complications more captivating and visually stunning than the moon phase.

Designed to show the phases of the moon and aid sailors in determining the tides, the moon phase is an aperture that usually sits front and centre on a watch’s dial. Many watchmakers believe it an integral addition on a timepiece for its importance in telling the passing of the months, and it’s often shown as a graphic depiction of the moon in its current phase.