All of these ceramic pieces were made between the late 16th century and the 19th century. The purpose of these bowls and jars were to hold tea or other foods and drinks. They are very plain, with little texture. I think the artist that created these ceramic pieces were more focused on the shape of the bowls, more than the color and texture. The ones made in the 16th and 17th century were more of a simple shape that was narrow at the bottom and wide at the top. As the years went on they started making vases\bowls with a curve and went from narrow to wide back to narrow. They also got a lot taller. Some artist would of got more detailed and painted to but others still choose to make theirs simple. Although the vases aren't painted in colorful, it is the shape that is unique about each different piece.