Cheng-hua: Year 16, Month 1, Day 7
17 Feb 1480
Military personnel and civilians in the Yun-nan border regions were prohibited from having communication with the external yi . At this time, the Regional Commander and Qian-guo Duke Mu Cong had memorialized: "Jin-chi and Teng-chong are strategic passes to the various yi. Recently, many native persons have violated the prohibitions and traded goods with the yi for precious stones. It is thus requested that a further prohibition be promulgated." The request was approved.
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 47, page 3491/92