Large bowl with carved vegetal design on exterior, flat base without foot. Five spur-marks.
According to Stevenson (1997: 234), this type of alms bowl was used to receive offerings of food that begging monks obtained. More commonly made of wood or unglazed clay, this type may have been used by monks of high rank.

References:
Stevenson & Guy, Vietnamese Ceramics, A Separate Tradition, 1997, p.234, cat.110
Stevenson, Wood, Truong, Dragons and Lotus Blossoms », Vietnamese Ceramics from the Birmingham Museum of Art, 2011, p.110 cat.60