Splash-glazed wares were made in the Tang dynasty primarily in Henan province, where several kilns that produced them have been found. The earliest discoveries were the kilns of Huangdao in Jiaxian, after which these wares are ofen named, though other kiln sites have been found in the area of Jiaocheng, Shanxi province. See Fen Xianming et al., Zhongguo taocishi, Beijing, 1982, p. 213. As can be seen on this jar, the brown glaze applied to the body typically stops short of the base. The pale blue splashes were applied after glazing, often poured onto the pot held in a sideways or an inverted position.
A similar jar is illustrated by R. Ward and P.J. Fidler (eds.), The Nelson-Atkins Musuem of Art: A Handbook of the Collection, New York, 1993, p. 294.