The bottom portion of a vessel, that comes in contact with the surface it rests on during normal use. A flat underside, lack any noticeable protrusions. Slightly concave bottoms can be counted in this category. During the T'ang and earlier periods, flat bottoms were the most fundamental and frequently seen base type. In later periods, they noticeable occurs on porcelain wares of the transitional period, mid 17th century, between the Ming and Qing dynasties.
See also: Shapes, ceramic