Grand Seiko caliber 9R96
Caliber 9R96 is a self-winding movement with column-wheel chronograph and GMT function, based on Seiko's Spring Drive technology.
As in conventional mechanical watches, the sole power source of Spring Drive is a mainspring that can be wound by the motion of an oscillating weight or by winding the crown. And just as in mechanical watches, the mainspring drives a series of gears that rotate the hour, minute and second hands. A rotor, connected to the end of these gears, generate a small electrical charge that activates an electronic circuit and quartz oscillator.