During the Nara period (8th century), Japanese ceramists sought to imitate Chinese sancai tri-color glazed ceramics created in the Tang dynasty (618–907). The resulting Nara sansai works, as they are known in Japanese, have gray, slightly yellowish clay bodies that are fired to a higher hardness than other works created up to that point. Ceramists first coiled clay cords to form a general structure, then shaped the vessel further using a potter’s wheel, smoothing out the surfaces using a flat wooden tool (rib). This stout, rounded pot has a wide shoulder that curves generously inwards towards the vessel bottom. The rim of its mouth is slightly raised and tilted inwards, with the top surface flattened. The vessel bears a widely flared base, at the bottom of which are three faint spur marks left behind by the kiln spur on which it sat to prevent it from touching and sticking to the kiln during the firing process. After firing, its external surface was painted over in white clay to form a ground of slip. Tri-color glaze was then applied to its outer body, while its inner surface and base were covered in a greenish transparent glaze. The shiny tri-color glaze is achieved by applying mainly green glaze over transparent glaze, then filling some of the gaps in using brown glaze.
Tang tri-color glazed ceramics came to Japan mostly in the Asuka period (6th–8th century), and heavily influenced the ceramics industry in the subsequent Nara period, giving rise to Nara sansai ceramics. Today, these are being excavated all over the nation, with many being discovered in and around Nara, where the capital was located at the time. In addition, the Shōsōin Imperial Repository has fifty-seven Nara sansai works in its collection, passed down through the ages. Although in China, Tang sancai ceramics were funerary goods created to be buried in graves, Japanese Nara sansai vessels were created for practical use, taking the vessel forms already found in pre-existing ceramic types such as haji and sue stoneware, as well as metal vessels. This jar, in particular, is notable for being one of the few extant works still fully intact.