Tian-qi: Year 3, Month 4, Day 26
24 May 1623
As the "bay yi" were to instruct in the use of firearms, the Minister of War Dong Han-ru and others memorialized three proposed arrangements: "1. On guarding against spies. In the places where the training is to be given, we should have the ward-inspecting censor assign officers from the warden's office, who will regularly carry out patrols to ensure that the outsiders are not able to spy and that secrets do not leak out. 2. We must lay a heavy burden of responsibility on those training. We should have the military headquarters select 100 crack troops from the Capital Training Divisions, and the various yi should be commanded to instruct them in the methods for making the gunpowder, loading and firing. We should also have two squad leaders supervise them in the training day and night. Idleness or laxness must not be permitted. 3. It is proposed that expenses be provided daily to the yi chieftains, interpreters and attendants, and that these be liberal. They should be supplied from the silver remaining from that set aside for Imperial rewards in previous years. The saltpetre, other materials and tools should be purchased at their appraised value." The Emperor approved this.
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 128, page 1729