Abstract: A basic clockwork, initially arranged in such a way as to comprise two supplementary indicators, of the date and of the days of the week, which have been removed, is provided with an additional module carrying supplementary indicators, which can number two, three or even four. These indicators being separate from the basic clockwork, their position can be chosen very freely by a constructor. In order to prevent having to provide the clockwork with one or several supplementary control members, for the correction of said indicators, a correcting mechanism of the basic clockwork, comprising a control stem operating a sliding pinion is used. A shaft of the sliding pinion has been extended up to a frame of the additional module and carries a pinion meshing, according to the sense in which the control stem is operated, either with a wheel belonging to a correcting gear train of one of the supplementary indicators, or with a pinion belonging to a correcting gear train of another supplementary indicator.