Bowls like these were used to mix pigmented lacquers (which were) then applied to utilitarian bowls or boxes. Once the bowl built up a large residue of lacquer they were rendered useless to lacquer workers and were burnished and polished by (or for) collectors.
These works became popular for collectors during the 20th century. The bowl is 12 1/2" in diameter & 2 1/2" in height. I added some photos from a book on these lacquer pieces for further context.The condition of the bowl reflects use.