A drive mechanism for two coaxial calendar members meant to rotate in stepwise manner about their common axis in a watch movement, comprising a drive member provided with two finger-pieces for actuating one of each of the calendar members, a calendar wheel connected to the gear-train and coaxial with the drive member, a coupling with angular play between the calendar wheel and the drive member, a cam rigidly connected to the drive member, a lever operating in concert with the cam, and a spring acting on the lever such that it will ensure an instantaneous jump of the two calendar members by rotation of the drive members after the latter has been brought into a given orientation by the calendar wheel. The invention is further characterized in that the contour of the cam is provided with a retaining notch operating in concert with the lever and limiting the rotation of the drive member under the influence of the spring.

A day-date mechanism which includes an annular "day" ring and an annular "date" ring having adjacent circles of pointed drive teeth and with an associated viewing window for display of day and date side by side. A rotary index pawl coupled to the drive train by a one-way intermittant motion transmitting connection produces an active stroke of movement once every 24 hours. Detent springs for the respective rings engage the drive teeth for completing each step of indexing movement. A manual reset lever is separately engageable with the respective rings for indexing the rings individually into set positions. The nature of the drive connection permits indexing of the rings by the manual reset lever at any time regardless of the position of the index pawl.