Watches have been in use for centuries and in some fundamental ways, they haven’t changed all that much. The core differences boil down to their internal movements.
The way a watch moves is in effect the engine that helps it to run and keep time. Watch movement (or “caibre”) is the powerhouse of a watch and supports its functioning as well as all its features. Watch movement is the internal mechanics of the watch, which moves the hands, keeps time and also powers additional features like an annual calendar, chronograph or dual time zone functioning.
Clearly, watch movement or calibre drives all of the functions of the watch and is essential to both its overall operation and ability to keep time. There are a wide variety of different specific watch movement iterations that have been created by watch designers and manufacturers over the decades; yet while there are countless patented proprietary designs and innovations in watch movement, there are actually only two main categories: mechanical and quartz.