Complications
Horological Complications Encyclopedia
Any function beyond the simple display of hours and minutes is a complication. Each record here covers definition, historical origin, how the mechanism actually works, its appearance in pocket watches, wristwatches and (where relevant) clocks, identification features and servicing notes.
Database
Browse complications
TimingSmall SecondsA subsidiary dial, usually below the centre, showing seconds independently of the main hour/minute display, driven directly off the fourth wheel of the going train.TimingSweep (Centre) SecondsA seconds hand mounted concentrically on the centre arbor and sweeping the full dial, rather than occupying a small subsidiary dial.TimingIndependent (Dead) Seconds — Foudroyante DistinguishedA seconds display driven by its own separate wheel train and detent, advancing in discrete jumps once per second rather than sweeping continuously, so it can be read to the exact second.See editorial status
TimingChronographA watch with an independent stopwatch function layered on top of ordinary timekeeping, started, stopped and reset by pushers, typically displaying elapsed seconds and minutes (and sometimes hours) on subsidiary dials.See editorial statusTimingFlyback ChronographA chronograph variant allowing the running hand to be reset to zero and instantly restarted with a single pusher action, without first stopping the timing function.See editorial statusTimingSplit-Seconds Chronograph (Rattrapante)A chronograph with two superimposed centre seconds hands that normally move together, allowing one to be stopped momentarily to read a split (intermediate) time while the other continues running, then snapped back into sync.See editorial statusTimingColumn Wheel (Chronograph Switching)A star-shaped, vertically pivoted wheel with raised columns used to coordinate the start, stop and reset levers of a chronograph in the correct sequence.Calendar & astronomySimple (Date) CalendarA calendar mechanism showing the date (and often day and/or month) which requires manual correction at the end of short months, because it does not account for months of fewer than 31 days.Calendar & astronomyAnnual CalendarA calendar complication that automatically accounts for months of 30 and 31 days, requiring correction only once a year at the end of February.See editorial statusCalendar & astronomyPerpetual CalendarA calendar complication that correctly tracks date, day, month and leap years without manual correction (other than for the rare centurial exceptions to the leap-year rule), for as long as the watch runs continuously.See editorial statusCalendar & astronomyDay-DateA calendar display combining a numerical date with a spelled-out day-of-the-week indication, typically shown side by side or in a double aperture at the top of the dial.See editorial statusCalendar & astronomyMonth IndicationA calendar display, usually a small subsidiary dial or aperture, showing the current month, generally as part of a triple (day-date-month) or perpetual calendar.Calendar & astronomyMoon PhaseA display, usually a rotating disc showing two moons behind an aperture shaped like the sky, indicating the current phase of the moon across the synodic (lunar) month.DisplayPower Reserve IndicationA dial display, usually an arc or subsidiary dial with a hand, showing how much running time remains before the mainspring fully unwinds.DisplayUp-and-Down IndicatorAn early, chronometer-associated form of power reserve indication, showing the winding state of the mainspring as 'up' (fully wound) through 'down' (run down) on a graduated arc.See editorial statusStriking & chimingAlarmA mechanism that sounds an audible signal at a pre-set time, using a separate striking train and hammer independent of the main timekeeping train.See editorial statusStriking & chimingQuarter RepeaterA repeating watch that, on demand, strikes the current time to the nearest quarter hour: hours on one tone, quarters on a different tone or two-tone combination.See editorial statusStriking & chimingFive-Minute RepeaterA repeating watch striking hours, then the number of completed five-minute intervals since the hour, offering finer time resolution than a quarter repeater without the full complexity of a minute repeater.See editorial status
Striking & chimingMinute RepeaterThe most refined common repeating grade, striking hours, quarters, and then the exact number of minutes elapsed since the last quarter, giving the time to the minute on demand.See editorial statusStriking & chimingGrande SonnerieA striking complication that automatically sounds the full hours and quarters as they pass, in addition to being repeatable on demand — combining the functions of a clock-style striking watch and a minute or quarter repeater.See editorial statusStriking & chimingPetite SonnerieA striking complication closely related to the grande sonnerie, automatically sounding the hours at each hour and a single tone at each quarter, but without repeating the full hour count at every quarter.See editorial statusStriking & chimingCarillon (Repeater)A repeating or striking watch using three (or more) gongs and hammers to strike the quarters in a melodic, multi-tone sequence rather than the simple two-tone pattern of a standard quarter repeater.See editorial status
PrecisionTourbillonA rotating carriage housing the escapement and balance, typically completing one revolution per minute, designed to average out positional timekeeping errors caused by gravity acting differently on the balance in different vertical orientations.PrecisionKarruselA rotating-carriage escapement mechanism, similar in purpose to the tourbillon, that averages positional timekeeping errors but rotates the carriage at a different and typically slower rate driven from a different point in the train.
Time zonesWorld TimeA display showing the current time in every major time zone simultaneously, typically via a rotating 24-hour ring read against a fixed ring of city or time-zone names.See editorial statusTime zonesDual Time / GMTA complication showing the time in a second time zone in addition to local time, typically via an independently adjustable additional hour hand, a 24-hour hand referencing a rotating or fixed bezel, or a subsidiary dial.See editorial statusCalendar & astronomyEquation of TimeA display showing the difference between mean solar time (the constant time kept by clocks) and true (apparent) solar time (as read from a sundial), which varies through the year due to the Earth's elliptical orbit and axial tilt.Calendar & astronomySidereal TimeA display of time measured against the fixed stars rather than the sun, running slightly faster than solar time (a sidereal day is about 3 minutes 56 seconds shorter than a mean solar day), used for astronomical observation.See editorial statusCalendar & astronomyAstronomical IndicationsA broad category of complications displaying astronomical phenomena beyond calendar and moon phase, including sunrise/sunset times, zodiacal position, planetary positions, star charts and celestial coordinates.See editorial statusDisplayJump HourA display in which the hour is shown in a numbered aperture (rather than by a conventional hand) and changes instantaneously — 'jumping' — from one hour to the next at the top of the hour, rather than creeping.See editorial statusDisplayRetrograde IndicationsA display in which a hand sweeps across a scale (rather than a full circle) and then jumps instantaneously back to its starting point once it reaches the end, used for dates, seconds, day or other indications.PrecisionDeadbeat SecondsA seconds display that advances in a single, sharp, discrete step once per second, as opposed to the small tremor of an ordinary lever-escapement seconds hand or the smooth glide of a high-frequency escapement; historically associated with the deadbeat escapement used in precision pendulum clocks.DisplayWandering HoursA display in which the current hour numeral itself travels along an arc of the dial, passing a fixed pointer or aperture that indicates the minutes, so that a single rotating hour numeral (rather than a hand) reads the time.See editorial statusTimingFoudroyante (Jumping Fractional Seconds)A hand that completes one full revolution of its own subsidiary dial per second, divided into fractions (commonly fifths, sixths or eighths of a second), jumping abruptly between each fraction rather than sweeping or ticking once per second like an ordinary seconds hand.See editorial statusCalendar & astronomyBig Date (Grand Date)A date display enlarged well beyond the size of a conventional single date window, typically achieved with two separate discs — one for each digit — rather than a single printed date ring, to improve legibility.See editorial statusCalendar & astronomyTriple CalendarA calendar complication displaying day, date and month simultaneously (often alongside moon phase), but without the perpetual calendar's automatic leap-year and month-length logic, so it requires manual correction after every short month.See editorial statusCalendar & astronomyZodiac CalendarAn astronomical calendar indication showing the sun's position against the twelve signs of the zodiac through the year, typically displayed as a rotating ring or disc printed with the zodiacal symbols and a fixed pointer marking the current sign.See editorial statusCalendar & astronomyLunar and Religious CalendarA calendar display tracking a lunar or lunisolar calendar system — such as the Islamic Hijri calendar or the Hebrew calendar — rather than, or alongside, the Gregorian civil calendar, typically used to indicate religious dates and observances.See editorial statusCalendar & astronomyTide IndicationA display showing the state of the tide — typically high, low, and the direction of change — for a given location, calculated from the relative positions of the sun and moon rather than from direct tidal measurement.See editorial statusCalendar & astronomySunrise/Sunset IndicationA display showing the times of sunrise and sunset for a given date and location, usually via two hands or discs read against a 24-hour scale, or a shaded day/night sector whose boundary shifts through the year.See editorial statusDisplayDay/Night IndicatorA subsidiary display, typically a rotating disc shaded to represent day and night (often with sun and moon or star motifs), that shows whether the main time display currently refers to the AM or PM half of the 24-hour day.Calendar & astronomyPlanetarium / Orrery IndicationA display modelling the relative positions and orbital motion of the sun, moon, earth and other planets, in the manner of a mechanical orrery, miniaturised into a watch or clock dial rather than presented as a standalone scientific instrument.See editorial statusPrecisionLinear and Double Power ReserveVariants of the power-reserve indication that depart from the common semicircular fan-shaped gauge, including linear (straight-line) scales and displays tracking two independently wound barrels rather than a single mainspring's state of wind.Striking & chimingSonnerie au Passage (Passing Strike)A striking mode in which the watch or clock sounds the hours (and sometimes quarters) automatically as each one passes, without being triggered on demand, distinguishing it from a repeater, which strikes only when activated by the wearer.
TimingChronographA watch with an independent stopwatch function layered on top of ordinary timekeeping, started, stopped and reset by pushers, typically displaying elapsed seconds and minutes (and sometimes hours) on subsidiary dials.See editorial statusTimingFlyback ChronographA chronograph variant allowing the running hand to be reset to zero and instantly restarted with a single pusher action, without first stopping the timing function.See editorial statusTimingSplit-Seconds Chronograph (Rattrapante)A chronograph with two superimposed centre seconds hands that normally move together, allowing one to be stopped momentarily to read a split (intermediate) time while the other continues running, then snapped back into sync.See editorial statusTimingColumn Wheel (Chronograph Switching)A star-shaped, vertically pivoted wheel with raised columns used to coordinate the start, stop and reset levers of a chronograph in the correct sequence.Calendar & astronomySimple (Date) CalendarA calendar mechanism showing the date (and often day and/or month) which requires manual correction at the end of short months, because it does not account for months of fewer than 31 days.Calendar & astronomyAnnual CalendarA calendar complication that automatically accounts for months of 30 and 31 days, requiring correction only once a year at the end of February.See editorial statusCalendar & astronomyPerpetual CalendarA calendar complication that correctly tracks date, day, month and leap years without manual correction (other than for the rare centurial exceptions to the leap-year rule), for as long as the watch runs continuously.See editorial statusCalendar & astronomyDay-DateA calendar display combining a numerical date with a spelled-out day-of-the-week indication, typically shown side by side or in a double aperture at the top of the dial.See editorial statusCalendar & astronomyMonth IndicationA calendar display, usually a small subsidiary dial or aperture, showing the current month, generally as part of a triple (day-date-month) or perpetual calendar.Calendar & astronomyMoon PhaseA display, usually a rotating disc showing two moons behind an aperture shaped like the sky, indicating the current phase of the moon across the synodic (lunar) month.DisplayPower Reserve IndicationA dial display, usually an arc or subsidiary dial with a hand, showing how much running time remains before the mainspring fully unwinds.DisplayUp-and-Down IndicatorAn early, chronometer-associated form of power reserve indication, showing the winding state of the mainspring as 'up' (fully wound) through 'down' (run down) on a graduated arc.See editorial statusStriking & chimingAlarmA mechanism that sounds an audible signal at a pre-set time, using a separate striking train and hammer independent of the main timekeeping train.See editorial statusStriking & chimingQuarter RepeaterA repeating watch that, on demand, strikes the current time to the nearest quarter hour: hours on one tone, quarters on a different tone or two-tone combination.See editorial statusStriking & chimingFive-Minute RepeaterA repeating watch striking hours, then the number of completed five-minute intervals since the hour, offering finer time resolution than a quarter repeater without the full complexity of a minute repeater.See editorial statusStriking & chimingMinute RepeaterThe most refined common repeating grade, striking hours, quarters, and then the exact number of minutes elapsed since the last quarter, giving the time to the minute on demand.See editorial statusStriking & chimingGrande SonnerieA striking complication that automatically sounds the full hours and quarters as they pass, in addition to being repeatable on demand — combining the functions of a clock-style striking watch and a minute or quarter repeater.See editorial statusStriking & chimingPetite SonnerieA striking complication closely related to the grande sonnerie, automatically sounding the hours at each hour and a single tone at each quarter, but without repeating the full hour count at every quarter.See editorial statusStriking & chimingCarillon (Repeater)A repeating or striking watch using three (or more) gongs and hammers to strike the quarters in a melodic, multi-tone sequence rather than the simple two-tone pattern of a standard quarter repeater.See editorial statusPrecisionTourbillonA rotating carriage housing the escapement and balance, typically completing one revolution per minute, designed to average out positional timekeeping errors caused by gravity acting differently on the balance in different vertical orientations.PrecisionKarruselA rotating-carriage escapement mechanism, similar in purpose to the tourbillon, that averages positional timekeeping errors but rotates the carriage at a different and typically slower rate driven from a different point in the train.Time zonesWorld TimeA display showing the current time in every major time zone simultaneously, typically via a rotating 24-hour ring read against a fixed ring of city or time-zone names.See editorial statusTime zonesDual Time / GMTA complication showing the time in a second time zone in addition to local time, typically via an independently adjustable additional hour hand, a 24-hour hand referencing a rotating or fixed bezel, or a subsidiary dial.See editorial statusCalendar & astronomyEquation of TimeA display showing the difference between mean solar time (the constant time kept by clocks) and true (apparent) solar time (as read from a sundial), which varies through the year due to the Earth's elliptical orbit and axial tilt.Calendar & astronomySidereal TimeA display of time measured against the fixed stars rather than the sun, running slightly faster than solar time (a sidereal day is about 3 minutes 56 seconds shorter than a mean solar day), used for astronomical observation.See editorial statusCalendar & astronomyAstronomical IndicationsA broad category of complications displaying astronomical phenomena beyond calendar and moon phase, including sunrise/sunset times, zodiacal position, planetary positions, star charts and celestial coordinates.See editorial statusDisplayJump HourA display in which the hour is shown in a numbered aperture (rather than by a conventional hand) and changes instantaneously — 'jumping' — from one hour to the next at the top of the hour, rather than creeping.See editorial statusDisplayRetrograde IndicationsA display in which a hand sweeps across a scale (rather than a full circle) and then jumps instantaneously back to its starting point once it reaches the end, used for dates, seconds, day or other indications.PrecisionDeadbeat SecondsA seconds display that advances in a single, sharp, discrete step once per second, as opposed to the small tremor of an ordinary lever-escapement seconds hand or the smooth glide of a high-frequency escapement; historically associated with the deadbeat escapement used in precision pendulum clocks.DisplayWandering HoursA display in which the current hour numeral itself travels along an arc of the dial, passing a fixed pointer or aperture that indicates the minutes, so that a single rotating hour numeral (rather than a hand) reads the time.See editorial statusTimingFoudroyante (Jumping Fractional Seconds)A hand that completes one full revolution of its own subsidiary dial per second, divided into fractions (commonly fifths, sixths or eighths of a second), jumping abruptly between each fraction rather than sweeping or ticking once per second like an ordinary seconds hand.See editorial statusCalendar & astronomyBig Date (Grand Date)A date display enlarged well beyond the size of a conventional single date window, typically achieved with two separate discs — one for each digit — rather than a single printed date ring, to improve legibility.See editorial statusCalendar & astronomyTriple CalendarA calendar complication displaying day, date and month simultaneously (often alongside moon phase), but without the perpetual calendar's automatic leap-year and month-length logic, so it requires manual correction after every short month.See editorial statusCalendar & astronomyZodiac CalendarAn astronomical calendar indication showing the sun's position against the twelve signs of the zodiac through the year, typically displayed as a rotating ring or disc printed with the zodiacal symbols and a fixed pointer marking the current sign.See editorial statusCalendar & astronomyLunar and Religious CalendarA calendar display tracking a lunar or lunisolar calendar system — such as the Islamic Hijri calendar or the Hebrew calendar — rather than, or alongside, the Gregorian civil calendar, typically used to indicate religious dates and observances.See editorial statusCalendar & astronomyTide IndicationA display showing the state of the tide — typically high, low, and the direction of change — for a given location, calculated from the relative positions of the sun and moon rather than from direct tidal measurement.See editorial statusCalendar & astronomySunrise/Sunset IndicationA display showing the times of sunrise and sunset for a given date and location, usually via two hands or discs read against a 24-hour scale, or a shaded day/night sector whose boundary shifts through the year.See editorial statusDisplayDay/Night IndicatorA subsidiary display, typically a rotating disc shaded to represent day and night (often with sun and moon or star motifs), that shows whether the main time display currently refers to the AM or PM half of the 24-hour day.Calendar & astronomyPlanetarium / Orrery IndicationA display modelling the relative positions and orbital motion of the sun, moon, earth and other planets, in the manner of a mechanical orrery, miniaturised into a watch or clock dial rather than presented as a standalone scientific instrument.See editorial statusPrecisionLinear and Double Power ReserveVariants of the power-reserve indication that depart from the common semicircular fan-shaped gauge, including linear (straight-line) scales and displays tracking two independently wound barrels rather than a single mainspring's state of wind.Striking & chimingSonnerie au Passage (Passing Strike)A striking mode in which the watch or clock sounds the hours (and sometimes quarters) automatically as each one passes, without being triggered on demand, distinguishing it from a repeater, which strikes only when activated by the wearer.