AMONG ZHANG HENG'S 張衡 (78– 139) major work in the fu genre, two themes stand out. He writes about Han capitals in a way to rival Ban Gu's 班固 (32– 92) celebrated pieces of the same topic. In fact, any study on Zhang Heng's “The Two Metropolises” (Er jing fu 二京賦) cannot be complete without a comparison with and reference to Ban's “The Two Capitals” (Liang du fu 兩都賦). Zhang Heng's mastery of the details of the Han capitals is also demonstrated in “The Southern Capital” (Nan du fu 南都賦).

His works on the second theme include three fu in the general area of “Feelings and Aspirations” (zhi 志), which is a category in the Wen xuan 文選. Both the “Contemplating the Mystery” (Si xuan fu 思玄賦) and the “Reply to Criticism” (Ying jian 應間) are included in his biography in the Hou Han shu 後漢書. The former also appears in the Wen xuan, along with his third fu on aspirations, the “Returning to the Fields” (Gui tian fu 歸田賦).

These six fu represent the best of his extant fu pieces, although there are at least ten other fu titles attributable to him. Most of these ten are either fragments collected in various leishu 類書 or completely lost with only titles mentioned in commentaries of other works. Even though the six fu are placed in two separate categories in the Wen xuan, they are for the most part united by their shared reliance on the use of hidden messages to convey his political ideals. Through his careful choice of words and subtle arrangement of contrasts, both between lines that are close-by and lines that appear in the opening and at the end with far distance in between, Zhang Heng composes fu that often contain significant messages. Here he seems to be following Yang Xiong's principle that the fu ought to contain rectifying messages behind its attractive surface— though the messages are sometimes so well hidden that they might also fall prey to Yang Xiong's criticism that the political messages of the fu are often buried in their rhetoric.