Tian-qi: Year 6, Month 1, Day 27
23 Feb 1626
Sun Yuan-hua, a secretary in the Ministry of War, memorialized requesting permission to use the Western Ocean platform cannon devices (西洋臺銃法) ... An Imperial order was issued noting: "Examine the existing Western Ocean cannons to determine whether or not they can be used, and investigate whether or not the instructors have taught people how to fire the cannons. Then make arrangements for defending the city walls." * Further, untranslated references to "Western Ocean" cannons can be found at Xi-zong juan 68.30a-31a and juan 69.20b.
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 131, page 3203