Early in 354, Zhang Zuo declared a clear break from Jin—a move that none of his predecessors had dared to do.
He completely repudiated the Jin era name Jianxing (declared by Emperor Min of Jin and used in at least some facility by every Zhang patriarch since his grandfather Zhang Shi (張寔)) and changed the era name to Heping.
Later that year, Zhang Zuo nevertheless sent his general Wang Zhuo (王擢) to assist the Jin general Sima Xun, who was commanding an auxiliary force in conjunction with the main force commanded by Huan Wen against Former Qin.
Zhang Zuo's rule, according to traditional accounts, was one filled with debauchery, cruelty, and extravagance.
He was said to not only had an affair with Princess Dowager Ma, but committed incest with all of Zhang Chonghua's daughters.
The news leaked, however, and Zhang Guan turned his army against the capital Guzang (姑臧, in modern Wuwei, Gansu).