 The relationship between father and son further deteriorated when, on a visit to Yulin, they hunted together—as Emperor Yang's guards were able to kill few animals, they blamed Yang Jian's guards for taking all of the animals, which made Emperor Yang further irritated at Yang Jian.Emperor Yang began to investigate Yang Jian's faults.Soon, one incident gave Emperor Yang the excuse to investigate further—as one of Yang Jian's favorite officials, Huangfu Xu () the county magistrate of Yijue County (伊闕, a suburb of Luoyang), was taken by Yang Jian to Fenyang Palace (汾陽宮, in modern Linfen, Shanxi) in contravention of regulations that county magistrates were not allowed to leave their counties without good cause.