In the thousand years covered by this volume the shih reached its highest level of development. A lyric form which, using a predominantly four-character line, had earlier been employed in the Confucian Book of Odes, it rose to prominence once more in the period under discussion. The new shih, which differed from the original form only in its use of a five- or seven-character line, became the best known and most characteristic of Chinese poetic forms.