A ball-jointed doll is any doll that is articulated with ball and socket joints. In contemporary usage when referring to modern dolls, and particularly when using the acronyms BJD or ABJD, it usually refers to modern Asian ball-jointed dolls. These are cast in polyurethane resin, a hard, dense plastic, and the parts strung together with a thick elastic. They are predominantly produced in Japan, South Korea and China. They commonly range in size from about 60 centimetres (24 in) for the larger dolls, 40 cm (16 in) for the mini dolls, and all the way down to 10 cm (4 in) or so for the tiniest of the tinies.
Though European and Egyptian articulated dolls made of wood and other materials date back hundreds of years, the modern era ball-jointed doll history began in Western Europe in the late 1800s. From the late 1800s through the early 1900s French and German manufacturers made bisque dolls with strung bodies articulated with ball-joints made of composition: a mix of pulp, sawdust, glue and similar materials. These dolls could measure between 15 and 100 cm (6 to 40 inches) and are now collectible antiques. The history of commercially produced Asian resin BJDs began in 1999 when the Japanese company Volks created the Super Dollfie line of dolls, which is still in production today.
The first Super Dollfies were 57 cm tall, strung with elastic, ball-jointed, and made of polyurethane resin; similar to garage kits, which were Volks' main product at the time. There are now roughly three main size categories for BJDs: large/full size, mini, and tiny. Although "Dollfie" is Volks' registered trademark, the size ranges used by Volks --Dollfie, Mini Super Dollfie and Super Dollfie--have come into colloquial use as a way to indicate the size categories of BJDs in general.
Large full size dolls, or SD (Super Dollfie) size, are around 60 cm. Roughly 1/3 scale, they usually represent fully grown teenagers or adult body types. There is also a range of even larger full size BJD, from about 70-90 cm tall.
Mini size dolls, or MSD (Mini Super Dollfie) size, are about 40 cm tall. There are two major categories of minis: those that are roughly in the same scale as the 1/3 full-size dolls and meant to look like children, and mature or slim minis which are meant to represent fully grown adults that are in 1/4 scale.
Tiny BJDs are under 30 cm tall. They are available in many different types and scales. While many BJD manufacturers' 1/6 scale lines are made to resemble children and toddlers in scale with larger BJDs (see for example Souldoll's "Soul-Little" line, Bobobie's "Petites", Angel of Dream's "Basic Tinies" ), a few tiny BJDs have mature bodies and are in the same 1/6 scale as fashion dolls like Barbie, about 21-30 cm tall. Asian companies making these mature tinies include Volks, Obitsu, SOOM, and Dollmore.
- Main article: Dollfie
Introduced in 1997--two years before the larger Super Dollfies--Volks' Dollfie was the first Asian line of 1/6 scale customizable dolls. As Dollfies are made from vinyl and hard plastic, not resin, they are sometimes excluded from the BJD category by resin purists, but it is more common to 'grandfather' them in on account of their history.
- Main article: Obitsu(brand)
Obitsu's 1/6 scale plastic figures are a 27 cm male, 27 and 25 cm females, and 21-23 cm males and females. They are aimed directly at the customizing hobby, with interchangeable parts, a wide range of options, and a unique structure built around a rigid internal 'skeleton'.
- Main article: SOOM
SOOM is a hugely popular Korean maker of resin BJDs offering one line of 1/6 scale/26 cm mature dolls, called "Mini Gems".
- Main article: Dollmore
This resin BJD company offers one 1/6 scale mature doll, available in an anonymous option or as a finished character doll called Melissa. Described as having a "well proportioned super model body", she is 32 cm tall and more fully articulated than the Mini Gems; she comes with two pairs of feet, flat and high-heel.