A little background on Chronometers
To conquer and rule over the seas, imperial ships needed accurate clocks to perform celestial navigation. The word chronometer is attributed to British master watchmaker John Harrison, who combined the Ancient Greek words chronos and metron (the measure of time).
The Greewich Observatory was the first to run Chronometer competitions in 1766. In Switzerland, the Geneva Observatory was the first to launch Chronometer competitions in 1790.
By 1823, the British admiralty could pay up to £ 300 (£12,576 today) for the best Marine Chronometers. After 1873, competitions were run every year in Switzerland. Other countries followed the idea, like the Kew Observatory in 1884, the Besançon Observatory in 1885 and a little later the observatories of Neuchâtel, Hamburg and Washington. Miniaturization and the introduction of the anchor escapement allowed to fit movements into pocket and wrists watches, so some of these were also subjected to chronometer testing during the XX century.
The trend eventually stopped in the last quarter of the XX century, when the miniaturization of electronics led to the creation of Quartz watches which were by nature far more accurate than mechanical watches. The legend says that Seiko, whose first watches did perform poorly, made a quantum leap when they submitted a watch that would have surpassed all the Swiss ones. The competition was quietly discontinued and no results were published. A few watch manufactures also started to run more stringent tests internally, making the use of an external body redundant.
In Switzerland, the Contrôle Officiel Suisse des Chronomètres was created in 1973 as a non-profit organization responsible for delivering Chronometer certificates (now based on ISO 3159) on uncased movement.
Nowadays, accurate time is supplied by atomic clocks, either broadcasted through radio waves or enclosed in GPS satellites. Yet watchmakers still use Chronometer certification as a guarantee of manufacturing quality. Rolex has always been the COSC’s biggest client, as they submit all of their mechanical watches for Chronometer certifications. Brands like Breitling and Omega have started submitting more of their watches for certification. The COSC also runs certification on Quartz movements, which is more stringent that that for mechanical movements, and Breitling has started to submit movements for that category too.
but Jaeger-Le-Coultre boasts internal tests that are far more stringent than ISO 3159. Watchmaker François-Paul Journe even questions the legitimacy of a “Chronometer” label after he used the name one of his watches that never underwent testing by the COSC. The strongest criticism of COSC certification is that tests are performed on the movement alone, which is arguably not a good indication of how well the movement will perform once it has been manipulated for fitting into a watch case.
The watchmaking boom that preceded the Subprime crisis led to the revival of Chronometer certifications. In the XXI century, Finnish-born master watchmaker and AHCI member Kari Voutilainen was the first to submit watches for certification by the Besançon Observatory. Patek-Philippe veteran Laurent Ferrier also decided to submit his watches to testing by the French observatory.
In 2009, the Le Locle horological museum and the Besançon Observatory jointly launched a Chronometer competition which clause were cleverly written to rule out non-European watch submissions.