Zheng-tong: Year 12, Month 3, Day 12
28 Mar 1447
In Yun-nan, the Xiao Dian police office was established in He-qu Subprefecture and the Gan-hai-zi police office was established in Nan Dian County, each with an establishment of one police officer. The following offices were abolished: Pu-piao, Zhen-yi Pass, Guan-shi Pass, Shan-da Pass, and that at Yu-nan Pass at Yong-ping, all under the Jin-chi Command, as well as that at the West Pass under Chu-xiong Guard.
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 29, page 2961