Also known as Adjustment. Optimizing the timekeeping of a movement at various temperatures and in various positions. Depending on the movement’s quality and on the degree of precision desired of it, various kinds of regulation can be performed. The regulation of most decent-quality watches is conducted in two positions (dial up and crown up). Running deviations between these two positions generally do not exceed 30 seconds per day. For precision regulation in conformance with official criteria, such as those of COSC, a movement must be regulated in five positions and at three different temperatures (8°, 23° and 38° C). If the testing is performed by an officially recognized institution and if the movement achieves or surpasses certain minimum values, then the timepiece earns the right to bear the designation “officially certified chronometer.” (See “chronometer”)

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