An automatic watch is a type of timepiece that winds itself using the natural motion of the wearer's wrist. Inside the watch, a small rotor moves as the wrist moves, transferring energy to the mainspring, which powers the watch. This means that as long as the watch is worn regularly, it will keep running without the need for a battery. Unlike quartz watches, which rely on a battery for power, automatic watches are often favored by enthusiasts for their craftsmanship and mechanical complexity. They are part of the broader category of mechanical watches, which also includes manual-wind watches that require regular winding by hand.