Bjd (ball joint doll) means "ball joint doll" or "ball joint humanoid". Refers to all kinds of exquisite spherical joints (humanoid dolls). Because the key parts are equipped with spherical joints, humanoid can make many postures close to real people.

BJD is mainly produced by East Asian countries (such as South Korea, Japan and China). The space for shaping dolls is very broad. BJD dolls can change clothes, make up, change hands, feet, hair and eyes. The charm of BJD to players is endless, and it gives players a free space to show their personality.