A ball-jointed doll is a doll that is can have its arms and legs moved because of a ball joint. During the 1930, artist Hans Bellmer, made dolls that had ball-joints and used them in photography. In 1980, Japanese traditional doll artists used ball joints with dolls. In 1999, Japanese doll company, Volks, popularized the ball-jointed doll made of urethane.
The main feature of the ball-jointed doll is its joints. These joints are round and can be taken apart. So you can assemble the joints and body parts to make a doll. There are double-joints and triple joints that can make doll more delicate.
The eyes, wigs, clothes and make-up on the dolls can be changed and people can design their 'own' doll.
Volks is the most popular company. There is also U-noa (Japan), D.O.D (Dream of Doll)(Korea), Luts (Korea), Blue Fairy (Korea), Iple House (Korea) and DZdoll (China).