The chronograph is a mechanism serving to measure time intervals. An addition to a watch’s traditional timekeeping functions, it is controlled via one or several pushbuttons, generally located on the side of the case. Successive presses thus serve to start, stop or zero-reset the chronograph hands.

Chronograph displays have given rise to countless interpretations, chiefly governed by the space available on the dial. Housed in wooden boxes, the first timers – capable of measuring short times only – provided a surface large enough to bear one dial per measured function: seconds, minutes, hours, as well as fractions of a second and a split-second hand. With the appearance of pocket chronographs and subsequently wrist chronographs, watchmakers faced the challenge of ensuring legibility within a small area. It is rare these days to see more than three additional counters on a watch face. On some models, one even sees two indications – such as the minutes and hours – appearing on the same portion of the dial, fitted on a shared axis. Especially since most chronographs have a small seconds hand also called “permanent” or “running” seconds. Directly linked to the going train of the watch, it testifies to the smooth running of the movement.

The large chronograph seconds hand is therefore often positioned in the dial center, for reasons of convenient reading. Once the mechanism is triggered, it moves in step with the balance and hairspring assembly, for example at a rate of six jumps per minute corresponding to a frequency of 3 Hz, or 10 jumps per minute meaning 5 Hz. This jerking motion has caused this hand to be referred to in French as the trotteuse (trotter). Meanwhile, the hand showing the measured minutes can move in three ways: “dragging”, “semi-instantaneous” or “instantaneous”. The first type moves slowly and regularly from one graduation to another; the second variety begins to move when the chronograph seconds hand reaches about the 58th second, driven by a mechanical fingerpiece; and the third kind jumps abruptly to the following graduation when the hand reaches the 60th second. Finally, if the hours are measured, the display moves slowly to perform a complete turn in 12 or 24 hours.

Over time, the chronograph has adapted to its various usages. Sport science and aviation inspired the development of lightning seconds (also referred to in English as flashing seconds), flyback and split-seconds functions. The existing interpretations also include regatta chronographs featuring a countdown version. Some mechanisms are also associated with measurement scales: tachymeter, telemeter, pulsometer, asthmometer and slide rule. A separate description is provided of all these versions.

Technically speaking, the chronograph mechanism can be either built into the watch movement, or mounted on the latter in the form of an add-on module, also called a “plate”. The former solution is considered nobler and involves greater development costs, while reducing flexibility when it comes to production; while the latter is less expensive and enables the use of a single base movement to which various complication plates can be added. But while the construction may vary, the operating principle remains the same: a control system (pushers, levers and control wheel) commands a coupling clutch, which engages or disengages the chronograph with the movement going train. The coupling clutch may be either horizontal – also known as lateral – or vertical. As for the control system, which transmits orders to the various levers, it is comes in two varieties: column wheel (the traditional technique) or cam-type (a more rational system). Zero-resetting is done via hammers that strike ‘heart cams’ fixed to the chronograph hand arbors.

Finally, one must be careful not to confuse the terms ‘chronograph’ and ‘chronometer’. The latter refers to a watch with a movement whose precision is certified in accordance with official standards. A chronograph may therefore be chronometer-certified, but not all chronometers are chronographs.

The chronograph is one of the most recent watchmaking inventions. The first modern version dates back to circa 1861 and we owe it to Henri-Ferréol Piguet, a watchmaker in the Vallée de Joux. On behalf of Nicole & Capt, he developed a pocket watch equipped with an additional seconds hand that could be started, stopped or reset to zero via a pushbutton built into the crown.

This invention was naturally preceded by a series of technical developments, starting with that of deadbeat seconds. When the seconds hand was introduced on pocket watches in the latter half of the 18th century, watchmakers’ efforts focused on a device serving to immobilize it in order to perform measurements. The first solution consisted in stopping the entire movement, as seen in the ‘deadbeat seconds watch’ by Jean Romilly (1754). In 1776, Geneva watchmaker Jean Moïse Pouzait became the first to start/stop the chronograph seconds hand at will, by means of a second going train and without disturbing the running of the movement. Nonetheless, this type of ‘independent deadbeat seconds’ watch still required the user to note the start of the measurement and to calculate the measured time.

A significant step was taken in 1816, when Parisian horologist Louis Moinet developed what he called a compteur de tierces. Well ahead of its time, this pocket timer – which by definition did not 

tell the time – displayed sixtieths of a second by means of a central hand, seconds and minutes on two separate dials, as well as hours on a 24-hour dial. Beating to the rhythm of 216,000 vph (30 Hz) – an extraordinary feat for the time –, it was also equipped with two pushers to start, stop and reset the mechanism. Described in Louis Moinet’s 1848 Watchmaking Treatise, this timer designed for astronomical instruments subsequently vanished until 2013.

In 1821, unaware of the work done by his fellow countryman, Nicolas Mathieu Rieussec – watchmaker by appointment to the King of France – unveiled at an equestrian competition a device capable of measuring the time taken to complete a horse race. Accurate to the nearest fifth of a second, it placed on demand a drop of ink on a rotating enamel dial housed inside a wooden case. This solution was developed in the absence of a zero-resetting device and gave rise to the name ‘chronograph’ (from the Greek for ‘writing time’). Today, the term ‘chronoscope’ (Greek for ‘observing time’) would be more appropriate, given that ink is no longer dropped on the dial. Nicolas Mathieu Rieussec was considered the father of the chronograph until the 2013 rediscovery of Louis Moinet’s compteur de tierces.

Continuous progress was made thereafter, focused on two main areas: miniaturization and precision timekeeping. In 1822, Frédérick Louis Fatton, a former student of Breguet, transformed Rieussec’s invention into a pocket timer. The first wrist chronograph, whose existence is confirmed by a Swiss registered design application in 1909, is the work of A. Ducommun-Muller and was soon followed by Heuer. Strongly involved in sport, the latter manufacturer would subsequently file a large number of patents in the field of high frequency. In 1916, its Mikrograph counter indicated hundredths of a second; and even through electric timing was definitively officialized in 1930, the race for precision has continued until the present day, including with the 2011 launch of the TAG Heuer Mikrotimer Flying 1000 (500 Hz) concept; and the 2012 introduction of the Mikrogirder concept, featuring a balance-wheel beating at 7,200,000 vph, meaning 1000 Hertz – and thus providing a mechanical indication of two thousandths of a second.

One should also note the 1969 launches of the first self-winding chronograph movements: the Chronomatic, produced by Dépraz-Bürgen for Breitling and Heuer-Leonidas; and the El Primero from Zenith, the first self-winding chronograph to beat at 36,000 vph