in 689, empress dowager wu made zhang acting "nayan" (納言) -- the head of the examination bureau (鸞臺, "luantai") and a post considered one for a chancellor. later that year, she made him acting "neishi" (內史) -- the head of the legislative bureau and a post also considered one for a chancellor. he was considered capable at both positions. however, his fall would come in the fall of that year. xu jingzhen (徐敬真), the younger brother of xu jingye the duke of ying, who had led an unsuccessful rebellion against empress dowager wu in 684, had been exiled to xiu prefecture (繡州, roughly modern guigang, guangxi), but fled from the place of exile and intended to flee north to eastern tujue. when he went through the eastern capital luoyang, the officials gong siye (弓嗣業) and zhang siming (張嗣明) gave him money to use in flight. when xu went through ding prefecture (定州, roughly modern baoding, hebei), he was captured and brought back to luoyang for interrogation. gong committed suicide, but both xu and zhang siming, in interrogation, implicated many officials, hoping that by doing so they could ingratiate empress dowager wu and her secret police officials so that they could be spared. zhang siming, in particular, claimed that when zhang guangfu was attacking li zhen, he secretly consulted fortunetelling books to try to see what the future might hold, and intentionally slowed down to see whether li zhen's rebellion had any hope. as a result of zhang siming's claims, zhang guangfu was arrested and executed with xu and zhang siming, and his assets were seized.