According to “The Age of Xia, The Records of the Grand Historian (Shiji)” of Sima Qian, the Xia Dynasty lasts about four hundred years from 2138 BCE to 1751 BCE. The Erlitou Culture found in Yensi Hsien of Honan Province in 1975 has been confirmed to be the Xia Dynasty. From the available Xia Dynasty jade artifacts found, we can see the rich variety of Xia Dynasty jade artifacts. They include jade ring, jade ax, notched zhang, notched bi-disk, arched plaques most of which are rather large and thin in size and have symmetrical lines. Parallel and intersection incised thin lines are used to form simple and concise motif. Moreover, many Xia jades have the trellis design consisting intersecting straight lines to form close and inseparable rhomboid shape that further to generate the exaggerated effect and the feeling of the mystery and solemnest that these ritual artifacts are carrying.
Although the existence of Xia Dynasty is still doubted by some typical historians disregarding the existence of “The Age of Xia, The Records of the Grand Historian (Shiji)”. In addition to “The Age of Xia, The Records of the Grand Historian (Shiji)”, the Chinese classic book Classic of Mountains and Seas (Shan Hai Jing) also contain some clues to its existence. Recently, some sources from the internet mentioned that the characters of the Xia Dynasty have a system different from the oracles of Shang Dynasty.
There are some sources claimed the characters based on the scripts from some doubtful jades. Both the jades and the characters cannot be verified before an objective authentication process has been done. The starting period of Xia Dynasty falls in the range of later period of Hongshan Culture around 2000 BCE. There are some jade artifacts have motifs of Hongshan Culture with ancient characters different from the oracle of Shang Dynasty. Those jade artifacts may be identified as Xia Dynasty jades or Hongshan Culture jades. It is possible that the Xia Dynasty was established by the offspring’s of Hongshan people. Some source claims that Xia Dynasty relates to the Liangzhu Culture. Sample Xi Dynasty jades are as follows: