By Yang Sung-jin
When a small North Korean submarine was found entangled in a fishing net off the South’s east coast in June, the conservatives here were duly piqued. They raised their hawkish voice calling for stepped-up military operations to block such a provocative infiltration. Given that South Korea and North Korea remain technically at war, having signed no treaty at the end of the 1950-53 Korean War, it is understandable that military preparedness receives top priority.
History also shows that whenever the country’s military power waned, a neighboring nation invaded the Korean peninsula, mowing down innocent people and causing immeasurable damage. The Japanese Invasion of 1592 and the Manchu Invasions of 1627 and 1636 are cases in point.
These examples, however, do not mean that Choson’s military strength was inferior in East Asia. The history of weapons development is the key to understanding Choson’s overall defense system.
Most military weapons were either long-ranged or short-ranged. The former indicated bows and arrows, various cannons and rocket guns. The latter are mainly swords and lances.
The Koreans have long favored bows and arrows — remember the gold medals of South Korean archers in the Olympics? — and that preference was fully reflected in the general military strategy of the Choson Dynasty.
While the long-range military weapons were vigorously developed, the Choson officials saw the development of short-range armory as much less important. In contrast, the Japanese greatly appreciated the use of swords, thereby enhancing their hand-to-hand fighting skills.
In addition to conventional weapons, the Choson soldiers also utilized gunpowder in order to launch a powerful attack by hauling arrows, stones and cannonballs.
Interestingly, gunpowder first appeared in the early 14th century in both Asia and Europe. As related technology advanced, the gunpowder-geared weapons replaced other conventional armory, eventually transforming the social structure. In China, Ming Dynasty united the entire country with the help of gunpowder; and in Europe feudalism fell apart as the eye-opening power of gunpowder undermined the role of knights in the Middle Ages.
Secret Formula Decoded
Gunpowder already had been used in Sung and Yuan China, but the manufacturing formula was top secret. It was Choe Mu-son who introduced gunpower for the first time in Korea in the late Koryo Dynasty.
According to a brief biography recorded in the Annals of the Choson Dynasty, Choe stressed the necessity of developing gunpowder in an effort to fight back the seaborne Japanese marauders. However, there was nobody who knew how to make it.
To find the secret, Choe met numerous merchants returning from China after trade and one of them replied he knew a little bit about the formula. The merchant was invited to Choe’s house and stayed for several days, providing rough, basic information.
Choe, a man of minor official status, asked the Todang (State Council) of the Koryo government to help him experiment with gunpowder, which resulted in scoffing and slandering.
Years later, he finally succeeded in persuading the Koryo court to establish “Superintendency for Gunpowder Weapons” in 1377, which functioned as an engine generating gunpowder weapons and a variety of cannons.
“Choe Mu-son was appointed as the director of the Superintendency for Gunpowder Weapons and he made a wide range of cannons employing gunpowder, including
hwa-po,'sin-po,’ and `chu-hwa'(a kind of rocket launcher). As the cannons were made, all the onlookers were deeply surprised and impressed by the power,” the Annals says.
In the fall of 1380, Japanese marauders aboard close to 300 ships invaded Chinpo in Cholla province. The Koryo government immediately appointed Choe Mu-son as the deputy commander in a mission to counterattack the Japanese and test the effectiveness of gunpowder.
Unaware of the existence of gunpowder, the Japanese pirates mounted an attack on the Koryo fleet approaching the port city of Chinpo. The result was devastating. At the order of Choe, the Koryo fleet showered explosives at the Japanese ships, all of which were burned down as a result.
Some of the Japanese pirates made it ashore and began to pillage town after town. A high-ranking Koryo general, Yi Song-gye (King Taejo), who later founded the Choson Dynasty, chased after and cleared the remaining marauders. In order to honor Choe’s prominent achievements, King Taejo gave Choe a high-ranking position in the government after taking power through a coup.
Choe had a son named “Hae-san.” Before Choe Mu-son died, he gave a book to his wife, saying “Give this book to the child when he becomes an adult.”
The widow kept the book and gave it to Choe Hae-san when he reached the age of 15 and was able to read. The book in question was about the secret formula to manufacture gunpowder. Choe Hae-san acquired the skills detailed in the book and worked for the weapon-developing agency in the government.
Another article dated on Oct. 18, 1409, mentions the name of Choe Hae-san. On that day, King Taejong, Choson’s third king, paid a visit to the test launching of “hwacha” (`fire cartwheel’) and gave a horse each to two inventors, Choe Hae-san and Lee To.
Hwacha was a movable launcher mounted on a cartwheel, from which gunpowder released dozens of arrows equipped with iron-made wings. This gadget had searing fire-power, highly effective in striking the enemy.
The hwacha was greatly upgraded and positioned in the frontier in 1451. Later the movable launcher was utilized against the Japanese Invasion of 1592, a token of what Choe and his son contributed to the advancement of firearms and weaponry.
A considerable number of articles related to the development of gunpowder-oriented weapons followed the time period when the Choe family cracked the secret code.
The most important factor in formulating gunpowder was to secure its basic material “yomcho” (kalium). Other essential ingredients included sulfur and charcoal. While sulfur was imported from Japan, specialists possessing the secret code of gunpowder produced yomcho only in Seoul.
On Sept. 19 in 1418, the weapon-making agency requested King Sejong to allow them to produce more yomcho: “We have so far reserved 3,316 kun (1989.6 kg) of yomcho, but we need roughly 4,000 kun for the year. Considering that there will be a shortage early next year, an increase is inevitable.”
Because of his keen interest in developing gunpowder weapons, King Sejong occasionally organized a test firing of a new type of cannon. On May 16, in 1424, an official of the Astronomical Observatory unknowingly reported that a national disturbance took place. The report said, “a sound of cannon fire was heard from the northern part of the palace at dawn.”
The astronomer, as expected, was severely chided by the king, not least because King Sejong himself made great efforts to enhance the level of gunpowder cannons, often missing sleep in order to work.