The simplest expression of a mechanical watch is a time-only display, with an hour hand and a minute hand. This kind of two-hand watch, which omits the seconds hand or any other function, is uncomplicated; it tells the time without any superfluous displays. Adding anything to this basic formula requires a more complicated mechanism, and thus any features of a mechanical watch beyond the hour and minute hands are referred to as complications.

Complications come in four general categories:

  1. Timing complications, such as a chronograph (aka a stopwatch)
  2. Astronomical complications, which show information about the position of the Earth relative to the heavenly bodies, such as a simple calendar to display the date
  3. Striking complications, which create sounds to track the passage of time, such as an alarm function
  4. Miscellaneous complications, such as a power reserve indicator, which don’t fall into the above broad categories
A. Lange & Söhne Grand Complication ref 912.032 featuring a perpetual calendar, monopusher rattrapante chronograph, grand sonnerie, petite sonnerie and a minute repeater. Image: Hodinkee

There is also the concept of a “Grand Complication”, which is a term used for watches that feature a complication from each of the three major categories; a timing complication, an astronomical complication and a striking complication. These are at the pinnacle of complicated watchmaking and serve as flagship timepieces for brands skilled enough to create them.

Complications can be desirable in a wristwatch for a variety of reasons. They may provide utility that the wearer will find useful, or they may increase the beauty and intricacy of a timepiece. A chronograph for example is a far more intricate machine than a time-only watch, and thus can be more desirable to lovers of fine craftsmanship and engineering. There’s also the matter of the exclusivity and status a complicated watch can confer; time-and-date watches are commonplace, but comparatively fewer people can hope to acquire a perpetual calendar or a sonnerie.

Below I will explore some of the most important complications and how they can be used, organised by category and complexity.

Timing Complications

  • Chronograph
Omega Speedmaster Professional calibre 3861, ref 310.30.42.50.01.001. Image: © OMEGA SA

This is a watch that features both a time display and a stopwatch function to be able to track elapsed time. The term chronograph means “time writer”, from the Greek words khronos (time) and graphos (to write). One of the first examples of a chronograph was created by Nicolas Mathieu Rieussec in 1821 to record the results of horse races for King Louis XVIII of France.

Reading a chronograph can be tricky at first, due to all the sub-dials cluttering up the watch face. On a three sub-dial chronograph, the time of day is read using a combination of the central hour and minute hands, along with a “running seconds” indicator on one sub-dial. The other sub-dials and the central second hand are inactive until the chronograph is started, using the upper button (called a pusher) positioned at 2 o’clock.

When the chronograph is engaged the central second hand activates and begins measuring seconds elapsed, and the two previously inactive sub-dials begin tracking minutes and hours elapsed, usually up to a maximum of twelve hours. Pressing the upper pusher at 2 o’clock once again stops the chronograph, and pressing the lower pusher at 4 o’clock resets it. Note that in a standard chronograph the timer must be stopped first before it can be reset.

Chronographs also commonly feature a fixed scale along the bezel called a “tachymeter”, followed by a series of numbers. Thus feature was originally designed for use by race car drivers, pilots, astronauts and other professions that needed to be able to gauge speed and distance. Using this scale you can determine either the speed of an object travelling between two fixed points (of either one kilometre, or one mile) or your distance travelled if you know your speed.

Here’ s an example of how this is done.

Let’s say you’re at a race track, and want to be able to tell the speed of a car moving between two check points that are a kilometre apart. As soon as the car passes check point one, start the chronograph. When the car arrives at check point two, stop it. Let’s say the car took 36 seconds to arrive at the second check point, which lines up with 100 on your tachymeter scale. That means the car was averaging 100kmph between the two check points.

Similarly, you can use a tachymeter to measure distance travelled if you know your speed. Let’s say you’re travelling at 90kmph and want to know when you’ve travelled one kilometre. Start the chronograph, and when the second hand reaches 90 on the tachymeter scale (after 40 seconds) you will have travelled a kilometre.

  • Flyback Chronograph
Carl F. Bucherer Manero Flyback chronograph with bi-compax (two sub-dials) layout, ref 00.10919.08.93.01. Image: Monochrome Watches

Quite simply, a flyback chronograph is one that does not need to be stopped first in order to be reset. This allows you to start timing something else immediately, with a single press of the bottom  pusher, and is useful for when rapid resetting or precision is needed. A standard chronograph by comparison first needs to be stopped using the top pusher, then reset with the bottom pusher, then started again with the top pusher in order to time a second event.

  • Rattrapante Chronograph (also known as the Double or Split Seconds chronograph)

Rattrapante is a French watchmaking term, meaning to “catch up”. A rattrapante chronograph uses two central second hands, one superimposed over the other, in order to be able to time two events at once. When the chronograph is started, both second hands begin moving in unison. The rattrapante will typically have a third pusher at either 10 or 8 o’ clock that will stop one of the two second hands, while the other continues to time the original event. Pressing the third pusher again causes the stopped seconds hand to jump back into its position underneath the moving seconds hand, “catching up” to it.

Using the race track example, if you were timing two cars, you could start the rattrapante chronograph when both cars left the starting line, stop one hand when the first car crosses the check point, and then stop the other hand when the second car crosses the check point. This allows you to tell how long both cars took, and the difference between their times at a glance.

Astronomical Complications

  • Date and Large Date
A. Lange & Söhne Grand Lange 1 with “outsize date” complication, ref 117.032. Image: © Lange Uhren GmbH

Although a simple date feature seems rather pedestrian and commonplace today, it is a complication that hasn’t been around for all that long. Rolex first introduced a self-changing date display with their Datejust collection in 1945. Prior to that if you wanted your watch to show the date, you had to spring for a full or a perpetual calendar.

The date complication is a form of simple calendar, typically showing the current date, expressed as a number from 1 to 31, on a single rotating disc. Less common is the Large Date, which uses two rotating discs rather than one to display the date. Windows on the dial show each disc, the first showing a number between 0 and 3, and the second showing a number between 0 and 9. A large date increases the legibility and aesthetics of the date display, as well as being a more interesting and slightly more complex mechanism. Another way to display this complication is the Pointer Date, which uses a hand on the dial to indicate the date via a chapter ring.

This complication doesn’t account for months with less than 31 days, and so it will need to be adjusted manually every other month to correct the date.

  • Day-Date
Rolex Oyster Perpetual Day-Date 40 in Everose gold with olive green dial, ref. 228235. Image: Time and Tide Watches

Another complication closely associated with Rolex, the Day-Date shows both the date and the day of the week, typically either in a window at 3 o’clock or in a curved aperture near the top of the dial at 12 o’ clock. This complication, like all simple calendars, requires adjustment every other month.

Rolex launched their flagship Day-Date collection back in 1956, with a unique bracelet made of solid gold. After being worn by former U.S. President Lyndon Johnson in 1965, the bracelet started being referred to as the “President”, a colloquial term that has since been extended to the Day-Date collection itself.

  • Full Calendar (also known as a Triple or Complete Calendar)

A full calendar shows the date, the day of the week, the month and also occasionally the moon phase in either windows or sub-dials on the watch face. Despite the amount of information on display, this complication is still technically a simple calendar as it doesn’t account for months with less than 31 days, and thus needs adjustment every other month.

  • Annual Calendar
Omega Globemaster Annual Calendar ref 130.33.41.22.06.001. Image: © OMEGA SA

The annual calendar is a relatively new complication to watchmaking, having been invented by Patek Philippe in 1996. This is more advanced than a simple calendar, as it can differentiate between months that have 30 days and those which have 31. An annual calendar will only need manual adjustment once a year (thus the name) at the start of March, due to the oddball month of February with its 28 days (and 29 in a leap year). Annual calendars offer a lot of the autonomy of a perpetual calendar at a much lower price point, with relatively affordable examples including the Omega Globemaster Annual Calendar and the Longines Master Collection Annual Calendar.

  • Perpetual Calendar

The perpetual calendar is an ancient complication, first invented in pocket watch form by Thomas Mudge in 1762 and then patented in wristwatch form over a century later by Patek Philippe in 1889. This complication is designed to always display the correct date. It accounts for 30 and 31 day months, the 28 days of February, and even leap years. A correctly set perpetual calendar will not need manual adjustment until the year 2100, when the Gregorian calendar skips the leap year in a once-per-century exception.

Jaeger-LeCoultre Master Ultra Thin Perpetual ref. 1302520. Image: Watch Collecting Lifestyle

Perpetual calendars vary in how much information is being displayed on the dial. The archetypal example is also a full calendar, showcasing the date, day, month, progress towards the next leap year, and sometimes a moonphase indicator. But simpler examples do exist, which limit the amount of information on display for a cleaner dial. Some of the most deceptive perpetual calendars are made by H. Moser & Cie, who favour extremely simple date-only displays with a small central hand to indicate the month.

Striking Complications

  • Alarm

An alarm watch typically features an additional hand that can be set to any time within a 12 hour  period.  When  the  desired  time  is  reached,  power  from  either  the mainspring or a subsidiary spring is released to move a small hammer that strikes a membrane (a “gong”) inside the watch case to create sound. This complication has largely been obsoleted by smartphones and bedside alarm clocks, but some manufacturers still produce them. The Tudor Heritage Advisor and Jaeger-LeCoultre Memovox are two modern mechanical examples.

  • Striking Time
A. Lange & Söhne Zeitwerk Striking Time ref 145.025, with hammers on the dial side to chime out the hours. Image: © Lange Uhren GmbH

A striking time watch is a mechanical complication that audibly chimes the hours (one chime for 1 o’clock, two for 2 o’clock, etc) again via a hammer and gong mechanism within the watch. The chimes occur on the hour in a passive fashion, requiring no intervention from the wearer, although they can usually be deactivated when the chiming isn’t desirable.

This style of watch was more commonplace before the invention of electrical lighting, as it allowed the wearer to more easily tell the time in the dark. Vision-impaired wearers also found this style of watch aided in telling the time before the widespread availability of electronic timekeeping. Modern striking watches are very rare, with one of the few examples still in production being the A. Lange & Söhne Zeitwerk Striking Time.

  • Repeater

A repeater is a kind of striking watch, but rather than automatically chiming on the hour, it requires activation in the form of pushing a button or lever, at which point it will immediately make a number of chimes corresponding to the current hour. This is also an ancient complication, having been invented back in 1680 by English clockmaker Daniel Quare and later refined by Thomas Mudge around 1750.

In addition to the basic repeater, there are also more advanced variations called quarter (and minute) repeaters with multiple hammers and gongs, capable of producing different sounds. When activated, they will chime out the current hour in one tone, and then the number of quarters (15 minute intervals) that have passed since the last hour using a second tone. A minute repeater will then also chime the number of minutes that have passed since the last quarter using a third tone.

For example, if the time was 2:20, a minute repeater (when activated) would chime twice (2 o’clock) in the first tone, then once (one quarter has passed since 2 o’clock) in the second tone, then five times (it’s been 5 minutes since that quarter) in the third tone. Modern examples can be found only amongst the most prestigious of watchmakers, although they are more common than the passive striking time complication.

  • Sonnerie
Credor Spring Drive Sonnerie with openworked dial. Three different chiming modes are available, indicated by the pointer hand at 6 o’clock: sonnerie, which chimes on the hour, silence, and “original”, which chimes three times every three hours like a traditional Orin bell. Image: The Naked Watchmaker

The sonnerie complication is similar to striking time, in that it passively chimes to denote the passage of time without intervention from the wearer. While a striking time watch only chimes the number of hours on the hour, a sonnerie can chime more frequently or in greater complexity. Typical examples include chiming the hours and quarters at each quarter-hour (a Grande sonnerie) or chiming the hours at the end of each hour as well as the quarters at each quarter (a Petite sonnerie).

Audemars Piguet deserve special mention here due to their ongoing collection of “Supersonnerie” watches, which aim to produce the clearest and loudest chimes of all sonneries. Japanese watchmaker Seiko also produces an extremely high-end sonnerie watch via their Credor brand, crafted in very limited quantities at the Micro Artist Studio in Shiojiri.

Miscellaneous Complications

  • Power Reserve Indicator (also known as Réserve de Marche)
Grand Seiko SBGA211 “Snowflake” with power reserve indicator at 8 o’clock. Image: Time and Tide Watches

A power reserve indicator is a sub-dial or additional hand on the watch face (or more rarely, displayed on the watch movement via a transparent case back) that shows how much power remains in the mainspring. This complication is often paired with perpetual calendars due to how difficult they are to properly reset if allowed to wind down. The power reserve indicator stands unique amongst complications as the only one to tell you something about the state of the watch, rather than the world around you.

  • Dead-Beat Seconds (also known as True Seconds)

This is a rare mechanical complication that changes the way the second hand moves. Rather than the near-continuous sweeping motion typical of mechanical watches, a dead-beat second hand ticks in one-second increments. This is designed to help reading time accurately to the second, and this complication was usually featured in watches dedicated to science and medicine where such precision was required.

At a casual glance, a dead-beat seconds mechanism could be mistaken for a quartz movement due to these one-second ticks. This could be desirable if you want a watch that flies under the radar, serves as a talking point with other enthusiasts, or if the historic uses by the scientific community is appealing to you. Jaeger-LeCoultre’s True Second Geophysic and Habring2’s Erwin collections are modern examples still utilising this niche complication.

  • Jumping Hour
“Time Bridge” on a Lange Zeitwerk, with jumping hour disk to the left, jumping minute disks to the right, and a small seconds subdial at 6 o’clock. Image: © Lange Uhren GmbH

Watches with this complication do not have a traditional hour hand that creeps slowly from one hour to the next; instead they indicate the current hour right up until the minute hand reaches 60, and then they jumps instantaneously to the next hour. This can be done with a retrograde hour hand, but more commonly it is done using a “digital” format time display of a numerals disk that rotates when the hour changes. This complication can also be paired with a jumping minute display, where the current minutes also jumps instantaneously when the seconds hand reaches 60.

A. Lange & Söhne has a long history of jumping hour and minute watches, ever since master watchmaker Johann Christian Friedrich Gutkaes (and his later son-in-law, Ferdinand Adolph Lange) crafted the Five-Minute Clock for the Semper Opera House in 1841. This clock inspired the design of the Zeitwerk collection with its jumping hour and minute displays, which was first launched in 2009.

  • GMT
Rolex GMT-Master II “Pepsi” ref 126710, with a red GMT hand to indicate 24hr time in a second timezone via the bezel. Image: Time and Tide Watches

Greenwich Mean Time was once used as an international time standard during the early eras of intercontinental travel. Glycine was the first brand to debut a true GMT watch capable of tracking two 24-hr timezones at once (the Airman, launched in 1953) but Rolex became better known in this arena when they debuted the GMT-Master in 1954, which went on to become the standard issue watch for pilots of the Pan American World Airways.

A GMT watch features a fourth hand (in addition to the standard hour, minute, and second hands) typically in conjunction with 24-hour time indicators on the bezel, to display the time in an alternate time zone. They also commonly feature an independently adjustable hour hand (IAHH, for short) that allows the hour to be moved forward or backwards via the crown without stopping the watch, for ease of use when crossing between different time zones.

  • World Time

A more advanced version of the GMT complication, a World Time watch can display the time in 24 time zones simultaneously. This complication typically features two bezels, one with markings for 24-hour time, and another which shows each of the major cities in 24 time zones. One bezel will slowly rotate, driven by the movement, and complete one revolution per day. This allows you to read the time in any time zone at a glance by finding the city and reading the corresponding 24 hour indicator next to it.

Omega Aqua Terra Worldtimer ref 220.12.43.22.03.001 with a rotating inner bezel and a laser-ablated world map. Image: Hodinkee

Typically each city will be colour-coded to show which timezones utilise daylight savings time and which do not, so that the wearer can calculate their local time inclusive of any DST changes. Patek Philippe is credited as being the first to bring a world time complication to a wristwatch in 1937, and the complication has remained synonymous with some of the brand’s most exclusive timepieces. However, much more affordable world timers can be had from other brands like the Tissot Heritage Navigator, the Montblanc Orbis Terrarum, and the Omega Aqua Terra Worldtimer.

Article first posted on Hailwood Peters