The three Cs: Chronograph, Chronometer and Certification are among the most discussed words in the horology industry but not always well understood by the broader public. In fact, the first two Cs are often confused – both words start with “chrono” which comes from Greek and means nothing more than “time”. However, the second part of the word is what makes the drastic difference in meaning. Chronometer, in fact, refers simply to the measure (Greek “metron”) of time (Greek “chrono”) and is used to identify watches with high accuracy. On the other hand, chronographs are part of the so called movements with complications and are intended to feature not only hours and minutes but also other measures (generally on secondary sub-dials). This means that a chronometer might be associated with a chronograph but this last might not necessarily be a chronometer. Finally “certification” generally applies to the chronometers and we will see specifically which one, how and why.



The basic expectation for a watch is to be able to measure the passage of time and generally via indicating hours and minutes. All other measures beyond those last are achieved via the so called “complications”. The chronograph is one of those complications. In fact, a chronograph is a mechanism that helps measuring elapsed time and it is often called stopwatch. Those kind of watches generally have extra sub-dials to indicate the new measures and extra button(s) to operate the complication (start, stop and reset functions).

The word chronograph means writing (Greek “graphe”) time (Greek “chrono”) and the first watches of this kind were actually indicating the elapsed time via writing on the dial so that the length of the mark would indicate how much time had elapsed. Notably this is the only thing they were capable of doing and only in a second phase the chronographs have been integrated with a standard watch movement.

There are mainly two types of mechanism used in a chronograph movement: the column wheel and the coulisse lever.

The column wheel is so called because the presence of an element that looks like the turret of a castle. This element is very small and complicated hence relatively expensive to manufacture and assemble. For this reason this kind of chronographs are generally the more expensive. When the chronograph pusher is actuated the column wheel turns and engages or disengages the gears that run the chronograph. In this context it is important to underline the technical difference between a mono-pusher and two-pusher chronograph. The mono-pusher is based on the use of a single button to operate the chronograph and it will need three ratchet teeth in between each element of the turret for the three functions: start, stop, reset. On the other hand the two-pusher is operated by two buttons and it will only need two ratchet teeth (start-stop) as the rest is done via a separate mechanism. As said, this mechanism tends to be used only on the high end watches like Rolex, Zenith (El Primero) and Omega.

The coulisse lever mechanism is sometimes referred to as cam-actuated chronograph. This type of mechanism leverages a series of lever and cam elements instead of the turret – those are generally easier to manufacture and assemble hence the lower cost and prestige associated to this kind of movement. In this type of chronograph the pusher actuates the cam, a heart shaped element (the coulisse) to starts, stop or reset. This kind of mechanism is available also on more accessible movements like the ETA/Valjoux 7750.

No matter whether based on the column wheel or the coulisse lever, the chronographs have invaded the horology world since their inception. They became very quickly the first choice for pilots, astronauts, runners and racers but they are also very appreciated by a broad consumer audience for their look.

A very interesting characteristic of a chronograph is also the fact that once people can measure elapsed time they can also measure many other things. For example via the use of a fixed bezel/secondary indication the watch might become a tachymeter and help the wearer measuring the speed; it can help measuring the heart’s pulse rate (see Longines Pulsometer Chronograph) or it can become a telemeter and help measuring the distance from an event that is possible to see/hear (see Junghans Meister Telemeter). Notably two chronograph mechanisms can be combined within the same movement to measure two events simultaneously – this is the famous rattrapante complication.   

column wheel and rattrapante


It is a general expectation for the watches to be accurate. However, due to the intrinsic structure of the movements, the many moving parts and different forces that act of them, mechanical watches are not always that accurate. Over time the need for precision, led to the development of more sophisticated watches and movement complications aimed at improving accuracy (e.g. tourbillon – see our post Tourbillon – King of watch “Complications”). The subsequent introduction of quartz movements (with fewer moving parts) further increased the availability of even more accurate watches at accessible price point. However, the passion for mechanical movements led to further innovation and some good modern chronometers might now be even more accurate than some quartz watches.  

The first chronometer seems to be credited to John Harrison (1761) who developed a so called marine chronometer meant to determine longitude by means of celestial navigation and accurate measure of time. Interestingly the word seems to come from Jeremy Thacker, a direct “competitor” of J.Harrison. The development of the first chronometers led to the introduction of the balance wheel and spiral spring still nowadays used in the mechanical movements. Over the years the original chronometer saw multiple innovations and improvements like, for example, the introduction of a nickel-steel alloy to manufacture the balance spring in order to compensate temperature variations.

As mentioned, many mechanical chronometers have then been replaced by the quartz movements. Those having less moving parts are less subject to the multiple forces hence they are generally more accurate. However, even the quartz watches are subject to the effect of temperature and aging of the quartz crystal which might impact the accuracy. Low temperature tends to make quartz watches run slower, conversely hot temperatures lead to the opposite. For this reason both mechanical and quartz chronometers accuracy is tested not only in respect to movement and shock but also in respect to changing temperatures. Notably considering the already relatively high accuracy of a quartz movement, it is very rare to find a “certified” quartz chronometer – conversely there are lots of watchmakers that seek certification for their mechanical chronometers.



Some watchmakers want to underline the high accuracy of the movements they manufacture – the chronometers – and in order to do that they work with third party/neutral organization in order to “certify” the movements. The most recognized organization, in this context, is the Contrôle Officiel Suisse des Chronomètres (COSC). Founded in 1973 by five cantons (Bern, Geneva, Neuchâtel, Solothurn and Vaud) together with the Federation of the Swiss Watch Industry (FHS), the COSC is a non-profit organization that tests Swiss-made chronometers. This does not mean that chronometers from other countries would not pass their certification but only that one of the requirements for achieving this badge is about having a Swiss-made chronometer.

Each movement submitted to the COSC is uniquely identified by a number (generally engraved on the movement) and it is thoroughly tested. If the movement passes the test successfully then it gets a certification number. The watches either pass or fail the test which lasts 15 days and is run with movements in five positions and at three different temperatures. Currently three laboratories test the movements (Bienne, Saint-Imier and Le Locle) and a couple of those location focus on the many Rolex submissions. In fact Rolex submits the largest number of movements by far - followed by Omega, Breitling, TAG Heuer and Panerai. However, despite the interest around this certification, only about 3% of Swiss watches are official chronometer certified.

Few watchmakers that want to further raise the bar then refer to the ″Fleurier Quality Foundation″ (created 2001). This is another organization that provides even stricter certification. Their certification, in fact, is based on five conditions: the watches should be manufactured 100% in Switzerland, they should first pass the COSC test, meet some aesthetic criteria, pass the Chronofiable test and the Fleuritest wear simulation test. As curiosity, Fleurier is a city in the Neuchâtel canton (Switzerland) which lives and breathes watchmaking since ever. In a similar way also Geneva has created a certification of excellence named Geneva Seal or Poinçon de Genève (French) – this refers essentially to the finish and decoration of watches made in the canton of Geneva. Chopard was the first watchmaker able to achieve the three certifications (COSC, Fleurir Quality and Geneva Seal) in the same watch L.U.C. triple Certification Tourbillon . It is also worth mentioning the METAS (Swiss Federal Institute of Metrology) certification which builds on top of the COSC. This certification is achieved by the watches that pass also some tests that simulate real life wearing conditions (like the Fleuritest) and demonstrate resistance to water and magnetic fields. This test has been developed in collaboration with Omega and their co-axial Globemaster is the first watch achieving this certification.  

Watches made in other countries have also similar kind of certification. The Japanese tend to follow a stricter standard with in-house testing while the Germans have similar standards and have a specific testing facility in Saxony at the Glashütte Observatory. French had for a while a similar kind of certification but nowadays is very seldom used.

watch certificate

In conclusion, chronographs and chronometers are quite different and one would not exclude the other within the same watch. On the other hand certifications relates to the chronometers and/or other characteristics of the watch like place of manufacture and aesthetic features. 



PS: if you want to know more about the different elements of a watch you can start from our post 17 Luxury Signs of World’s Most Expensive Watches


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