One of the key developments in medieval history was the creation of gunpowder weaponry. Throughout the medieval world, it would greatly change how war was waged. The Annals of King T’aejo includes an account of how gunpowder weapons were introduced to Korea.

The Veritable Records of the Chosŏn Dynasty (Chosŏn wangjo sillok) is a comprehensive historical record documenting the reigns of Korea’s Chosŏn Dynasty kings (1392–1897). Compiled by court historians, it provides a detailed, daily account of political events, diplomatic affairs, military campaigns, and governance. The records were written with strict historiographical principles, aiming for accuracy and impartiality, and even the Korean kings could not alter them.

The records began with the reign of King T’aejo (1392–98), the founder of the Chosŏn Dynasty. The Annals of King T’aejo covers only seven years but runs nearly 800 pages in English translation. It offers a vast amount of information, ranging from simple weather reports to plans put forward by government officials. Within its pages, you can also find a record of Korea’s earliest use of gunpowder weapons.

An entry from the year 1395 begins by noting that Ch’oe Musŏn, assistant grand councilor-without-portfolio, had died. It then goes on to offer a short biography of the man and his interest in military tactics and technology.

Years earlier, Korea was occasionally raided by Japanese pirates. Musŏn lamented, “There is nothing better than gunpowder for suppressing Japanese marauders, but in our country no one knows about it.” Determined to acquire this technology, he sought its secrets from Chinese merchants. When he met a merchant who had some understanding of gunpowder weapons, Musŏn brought the man to his home and spent several weeks learning from him.

It took several years before Musŏn could convince government officials to build these weapons, but his persistence finally led to his appointment as the first superintendent of the Superintendency for Gunpowder Weapons. The annals then note:

The manufacture of gunpowder soon led to the manufacture of a number of gunpowder weapons of various names. The names of the artillery are these: general-in-chief (taejanggun), two generals (ijanggun), three generals (samjanggun), six-stone ball cannon (yukhwa sŏkp’o), fire cannon (hwap’o), and trusty cannon (sinp’o). The other fire weapons operated by gunpowder are these: gunpowder tube (hwat’ong) and rocket-launched arrows of different names, such as hwajŏn, ch’ŏllyŏngjŏn, and p’iryŏngjŏn. In addition, there are shrapnel bombs and grenades called chillyŏp’o and ch’ŏlt’anja, the incendiary five-dragon arrow named ch’ŏnsanoryongjŏn, and arrows of flying fire and rockets of various names, such as yuhwa, chuhwa, and ch’okch’ŏnhwa. When these weapons were made, everyone who saw them was surprised and greatly admired them.

Musŏn would get to test out these new weapons in 1380 when a Japanese fleet of 300 ships attacked the southwest corner of Korea. He was appointed assistant military commander and sent there with ships equipped with gunpowder weapons. The annals continue:

Unaware that the Koreans possessed gunpowder weapons, the Japanese marauders clustered their ships together and fought back. However, Musŏn’s cannons devastated their fleet, completely destroying them. Having lost their ships, the Japanese enemies came ashore and plundered the inland areas while fleeing, until they reached Chŏlla and Kyŏngsang Provinces and finally assembled at Unbong in Chŏlla Province. At this time, the king [T’aejo], who had become supreme commander of our army, completely wiped them out with the help of other commanders. Thereafter, the invasion of Japanese marauders gradually decreased, and some of them voluntarily surrendered to our authorities one after another, so our people on the seacoasts were able to recover their livelihood. Though this happened due to the help of Heaven granted to our virtuous king, Musŏn’s contributions were no less significant.

When T’aejo ascended to the throne in 1392, he honored Musŏn with a prestigious rank in recognition of his contributions. After Musŏn passed away, his son Hae-san was given a book when he turned 15—a guide to manufacturing gunpowder. Later, Hae-san would rise to the position of vice director of the Directorate of Armaments.

The Annals of King T’aejo: Founder of Korea’s Chosŏn Dynasty is translated by Choi Byonghyon. Click here to learn more about this book.