Manual winding is the original mechanical-watch winding system. The wearer winds the crown 30-50 times per day; the action tensions the mainspring; the spring runs the watch for the next 24-72 hours depending on power reserve. The system is mechanically simple: no rotor, no auto-winding train, no extra components; the movement can be made thinner (no rotor mass on the back) and the case-back can show a clean view of the movement without rotor obstruction.
Automatic winding was invented by Abraham-Louis Perrelet in 1777 for pocket watches but became commercially viable for wristwatches only in the 1920s-30s. John Harwood patented the first commercial wristwatch automatic (1923, bumper rotor); Rolex Oyster Perpetual (1931) productionised the modern central-rotor automatic. The rotor sits on the back of the movement, swings with wrist motion, and winds the mainspring through reverser wheels (most calibres) or pawl systems (IWC Pellaton, Seiko Magic Lever).
"Wind it once a day. Look at the dial. Look at the wrist. Pretend, for thirty seconds, that you are not in a hurry."- Watch enthusiast on the manual-winding ritual
The practical difference for owners: automatic watches are convenient (worn daily, never wound; rest in a watch winder if multiple watches rotate); manual watches require daily attention (a 30-second winding routine each morning). Automatic watches are thicker by ~1-2mm because of the rotor; manual watches achieve the slimmest cases (sub-2mm haute-horlogerie ultra-thins).
Modern volume share: roughly 85% of mechanical watches sold are automatic. The volume tier (ETA 2824, Sellita SW200, modern Hamilton, Tissot, Tudor, Omega) is automatic-only; manual is reserved for specific aesthetic and engineering choices (ultra-thin dress watches, traditionalist chronographs, certain haute-horlogerie complications).
Manual chronographs retain a strong following in vintage-chronograph collecting: the Speedmaster Professional Moonwatch remains hand-wound (NASA-flight-qualified 1965 with manual Cal. 321; modern Cal. 3861 also manual); the manual Daytona 6263/6265 era runs through 1988. Manual dress watches: Patek Philippe Calatrava 5196, Lange Saxonia Thin, AP Royal Oak Jumbo Extra-Thin (Cal. 7121 manual). The manual choice signals traditionalism + slim case.