The hammer spring is fitted.
This the hammer part and the flat surfaces at the upper and on the left will strike the chronograph runner hearts to reset the counters. These are buffed.
And the hammer fitted.
Finally, the hour recorder yoke that will transmit the actuation to the dial side of the movement is fitted. It extends through the plate and will be seen on the dial side later. This side is complete.
The movement is turned over to fit the dial side components which control the hour recorder.