Watch hacking, also referred to as the seconds hand halt mechanism or seconds stop function, is a feature that allows the watch wearer to stop the movement at will. In the case of our Orient in house caliber, this is achieved by pulling the crown out to the time setting position. Doing so causes the hacking lever to stop the balance wheel and gear train of the watch. Whereas an automatic watch will continue to run whether the crown is pulled out completely or not, this results in the seconds hand to completely stop.
Although it is now a more prevalent feature in today’s watches, the hacking movement was widely used in the early 20th century, particularly with military timepieces-- it was especially useful and advantageous to coordinate watches during wartime. Nowadays, this feature is useful in maintaining timekeeping accuracy. For example, wearers can synchronize their watch with a more accurate clock (such as an atomic clock) in order to track time deviations and ultimately develop a basic understanding of a movement’s “performance“.
Another kind of “hacking” that you may experience or read about is called “back hacking”, which is a common occurrence for automatic watches. As mentioned, pulling the crown out to the time setting position does not stop the seconds hand on a generic automatic movement. “Back hacking” involves moving the hour and minute hands counter clockwise which in turn causes the seconds hand to move backwards as well. This is a well-documented method to attempt synchronization of an automatic watch with another clock. And while “back hacking” is sometimes unavoidable, doing it repeatedly is not recommended. Why? Because it puts unnecessary stress on the gear train, balance wheel and escapement. Regular mechanical watch hacking stops the gear train and balance wheel completely. “Back Hacking” forces them to move in the opposite direction, which is something they were not specifically built to do. That said, avoiding any kind of strain on the movement will improve its lifespan.