Treatise on Armament Technology, Volume 239

When Song Yangqian submitted his memorial to the throne, it was found to be at odds with the consensus of the imperial court. Consequently, he resigned from his post claiming illness, and Sun Kuang was appointed as his successor.

At this time, the envoy Naitō Jōan referred to in the text as Xiaoxifei (小西飛), a subordinate of the Japanese general Konishi Yukinaga returned to report on his mission and formally requested that the investiture of the Japanese leader Toyotomi Hideyoshi proceed. However, because the Japanese original: wo (倭) forces were still entrenched in Busan, the Emperor summoned the envoy to the court for questioning.

Naitō Jōan prostrated himself literally "bowed his head to the ground" (稽顙) and said:
"The army remains there only to await the arrival of the Imperial Envoy who brings the investiture; they do not harbor any other intentions."

The court then ordered a royal seal to be cast and dispatched Li Zongcheng (the eldest son of the Marquis of Linhuai) as the primary envoy, with Vice General Yang Fangheng as his deputy, to travel there and complete the investiture.

At this time, Shen Weijing believed that because of his many achievements, he should have been appointed as the sole envoy. He felt that even if he were not the lead, he should at least have been the official assistant. Instead, neither role was granted to him. Furthermore, Li Zongcheng was a pampered youth literally "silk trousers" (紈袴), a term for incompetent children of the nobility who understood nothing of affairs of state. He frequently insulted and berated Shen Weijing.

Shen Weijing looked for a way to place Li Zongcheng in a difficult position. Since the Japanese were still clinging to their stronghold in Busan and were unwilling to leave easily, the two envoys were effectively detained in the Japanese camp for an entire year. Sensing Li Zongcheng's distress and anxiety, Shen Weijing used alarmist talk to terrify him. Li Zongcheng eventually became so frightened that he abandoned the imperial decree and the seal and fled.

The imperial court subsequently ordered the arrest of Li Zongcheng and appointed Shen Weijing to serve as deputy to Yang Fangheng. It was only at this point that the Japanese generals Konishi Yukinaga original: Xingzhang (行長) and Katō Kiyomasa original: Qingzheng (清正) finally began to withdraw their troops.