Each of the four plain bowls measures about 11.1cm in height, 21.1cm in mouth diameter, and 7.9cm in bottom diameter. Their light white color shows that glaze was well applied. Each of their inside bottom shows inscribed Chinese characters “天” (cheon), “地” (ji), “玄 (hyeon), and “黃” (hwang). At that time, there were warehouses with the same names, where such bowls were kept, inside Gyeongbokgung Palace. Thus, it is believed that these names may be associated with them. It appears that they were made in a state-run kiln in Gwangju, Gyeonggi-do as those to be supplied to the royal court based on the fact that they were made from very carefully selected soil, their glaze was applied evenly, they display a pure white color, and their bottoms appear to be neat and even.