In May 1374 (the 23rd year of King Gongmin’s reign, Hongwu 7), Goryeo requested gunpowder and firearms from the Ming Dynasty, to which Emperor Hongwu responded positively. However, he also required Goryeo to send sulfur and saltpeter, the raw materials for gunpowder, to Ming. That year saw the assassination of King Gongmin and the incident involving the Goryeo envoy Kim Eui, who murdered and kidnapped a Ming emissary, leading to a break in diplomatic relations between the two nations for about a decade. During this period, gunpowder was not mentioned in Goryeo-Ming diplomacy. However, in later interactions between Joseon and Ming, there are frequent references to Emperor Hongwu bestowing gunpowder, and during King Sungjong’s reign, this became a pretext for the establishment of official trade in ox horns between Joseon and Ming. Emperor Hongwu, immediately after founding the Ming Dynasty, not only prioritized coastal defense to address the problem of Japanese pirates plundering China’s coastal regions, but also paid special attention to Goryeo’s coastal defense, consistently urging the reinforcement of coastal defenses in Goryeo-Ming diplomacy. In response, Goryeo used this as a pretext to request gunpowder from Ming. Given that Ming’s diplomacy with Japan, aimed at suppressing the pirates, was facing difficulties at the time, Emperor Hongwu partially accepted Goryeo’s request, sending a small amount of gunpowder and firearms. This event later became a diplomatic pretext for both Joseon and Ming in their interactions during the Joseon Dynasty.