Complication

A complication is any function a mechanical watch performs in addition to showing hours, minutes and seconds. A date window is a complication. So are a chronograph, a second time zone, a moonphase, a power reserve indicator, an alarm, a perpetual calendar and a minute repeater. The word comes from the workshop rather than the marketing department: every added function complicates the movement, adding parts, consuming energy and creating new ways for it to go wrong.

The part count makes the point. A plain three-hand automatic runs to something on the order of 100 to 140 components. Add a cam-operated chronograph in the style of the Valjoux 7750 and the figure roughly doubles. A perpetual calendar adds a further module built around a 48-month program wheel, a cam whose profile encodes the length of every month in a four-year cycle including February 29. Each of those parts needs space, energy from the same mainspring, and attention at every service.

How they are grouped

Complications fall into rough families. Calendar functions run from a simple date to an annual calendar (which knows the length of every month except February) and a perpetual calendar (which handles February and leap years too). Timing functions cover chronographs and their variants. Travel functions cover dual time, GMT and world time displays. Astronomical functions include moonphase and equation of time. Chiming functions run from a simple alarm to the repeaters, which strike the time on demand.

The practical difference inside a family is how often the thing needs your attention. A simple date needs correcting in five months of the year. An annual calendar needs one correction, on March 1. A perpetual calendar needs none until 2100, which is not a leap year under the Gregorian rule and which no ordinary perpetual calendar anticipates. Our guide to annual and perpetual calendars works through the distinction, and watch complications explained covers all six families in detail.

The term grand complication is used loosely for a watch combining several of the most difficult functions, typically a chiming complication, a chronograph and a perpetual calendar. There is no governing body that defines it. The record attempts give a sense of the ceiling: Patek Philippe's Caliber 89 pocket watch of 1989 carried 33 complications, and Vacheron Constantin's Reference 57260 of 2015 carried 57.

On a spec sheet

Complications appear under a heading like Functions or Indications, and the useful information is usually in what is left out. Two things are worth establishing before you buy.

First, module or integrated. Many functions are added as a separate plate bolted onto a simpler base caliber rather than designed into it. A module adds height, often changes the pusher feel, and means a watchmaker must lift it off before reaching the base movement. Neither approach is automatically better, and the specification sheet rarely says which one you are buying; a caliber number and a thickness figure usually tell you more than the marketing copy.

Second, whether the correction is quick. A quickset date can be advanced straight from the crown; without it you run the hands through 24 hours for every day. The same question applies to a GMT hand: an independently jumping local hour hand is a genuinely different watch from one where only the 24-hour hand can be moved.

What it costs you

Each complication is a running commitment. A chronograph adds parts that wear and lengthens a service: a full service on a three-hand automatic runs to an indicative $250 to $500 at an independent in the United States before sales tax, while a chronograph is more often $700 to $1,200. Those are indicative figures that move with the shop and the caliber; see what a watch service costs. A perpetual calendar must be kept running or reset carefully, which is one of the few genuine arguments for a winder. Anything with a date needs care around the hours when the change is under way, conventionally about 9pm to 3am: park the hands at 6 o'clock before touching the quickset.

Common misconceptions

More complications does not mean a better watch. A time-only watch with a superbly finished, well-adjusted movement can be more expensive, more accurate and more satisfying than a cluttered multifunction piece.

Several things sold as complications are not. A sweeping seconds hand is just the seconds display. A date magnifier is a lens. A rotating dive bezel times an interval but belongs to the case, not the movement, and nothing inside the watch knows it exists.

A tourbillon is the opposite case: it is genuinely difficult, but it displays nothing. It is a regulating device that averages out positional error, which is why it is better understood alongside the escapement than alongside the calendar, and why whether it is worth it is a separate question from what it does.