(14) Facts and Faulty Myth About Kobukson

By Yang Sung-jin

Last week, numerous events and ceremonies were held across the nation to commemorate the 400th anniversary of the death of Admiral Yi Sun-shin (1545-1598), one of Korea’s most respected military heroes. Yi was born on April 28th.

Admiral Yi is widely admired by the Korean people because he defeated the Japanese forces in the 1592-98 Hideyoshi Invasion. Furthermore, most Koreans are proud of the historical fact that Admiral Yi invented the iron-clad fighting battleship named “kobukson” (turtle ship in Korean), which greatly helped beat off the Japanese naval forces during the war.

But there is a faulty myth behind the worship of Admiral Yi, even though he certainly deserves respect. In particular, the kobukson is at the center of myth-making by historians.

When asked on how many kobuksons might have existed around the Hideyoshi Invasion, ordinary Koreans are likely to put the figure around dozens or more.

But, only three kobuksons were assembled and employed for the actual sea battles against the Japanese. Even this figure is not entirely rock-solid.

Some historians argue the Choson naval force had at least five kobuksons at that time.

Another fact to remember is that the kobukson, or at least its prototype can be found in documents far earlier than the Japanese invasion of the late 16th century.

In the CD-ROM Annals of the Choson Dynasty, the first ever reference to the word “kobukson” is found in an article dated Feb. 5, 1413.

King Taejong, then passing by Imjin Island, was reported to have watched a mock battle between a kobukson and an imitation of a Japanese battleship.

Also, in 1415, official Tak Shin reported to the king that the turtle ship should be developed further because it is almost indestructible from collision with enemy’s ships.

Some scholars go so far as to put the origin of the kobukon around the late period of the Koryo Dynasty (918-1392), as part of a bid to counterattack the Japanese seaborne marauders who pillaged the seashore villages of the Korean peninsula.

Most troubling is the lack of credible historical documents, which has long intensified disputes over the origin and actual look of the kobukson, providing little academic foundation to authentically restore the iron-clad battleship.

The most authoritative record about the kobukson to date is an article of the Choson Annals dated on May 1, 1592. The document reveals that Admiral Yi made the kobukson in the course of building up the military force.

According to the document, the kobukson was covered with thick wood blocks, with the cross-shaped narrow paths grooved on top. In the space between the paths stood sharp swords and pikes. These life-threatening weapons were camouflaged with a sheet or grass so that the enemy could mistakenly jump on the cover to death.

The ship also bore the head of the dragon, the legendary creature of Asian culture, through which a cannon fired. Moreover, six cannons were installed on each side of the ship, while the soldiers could hide behind the sturdy shield with utmost safety. The tail of the ship was equipped with a firearm, as well.

The speed of the kobukson seemed fairly quicker than other ships. The same document states, “The kobukson dashed into battle at will, destroying enemy ships as if the wind tossed them upside down.”

Historical Prediction

Admiral Yi started developing a new type of kobukson as soon as he was appointed as left naval station commander of the Cholla province in 1951, just one year before the devastating war broke out.

According to the diary written in 1952 by Admiral Yi himself, he received hemp clothes for the kobuskon on Feb. 8 and tested the firearms on the new battleship on March 27.

Coincidence or not, Admiral Yi conducted the final test of other cannons using the kobuskon on April 12, completing the kobukson project. And the very next day, the 200,000 strong Japanese army aboard 700 battleships across the sea moved in to attack the Choson Dynasty.

It was about two months after the breakout of the war that the kobukson went out to the sea near Tangpo to confront the Japanese naval force for the first time. In the sea battle directed by Admiral Yi, the kobukson proved its strategic power, spearheading the historical victory of the Choson naval force, while crushing some 30 Japanese battleships.

But why was the kobukson so effective in gaining the upper hand in the sea battle over the Japanese forces? First of all, the structure of the kobukson covered with the lethal pikes and swords on top prevented the Japanese army from moving too close, which led to the Choson’s victory in the end.

At the time, the Japanese army was superior at hand-to-hand fighting through numerous battles during the 100-year-long Japanese internal war known as the “Warring States Period.” Such tactics were also applied to the sea battle: the Japanese soldiers jumped on the deck of the enemy ships and began the deadly hand-to-hand fighting.

Furthermore, it was the highest honor to be designated as the first person allowed to jump on the enemy ship.

But when it came to the kobukson, the honorable jumping meant an immediate death.

Even scarier was the incredible speed of the kobukson hitting and scuttling the Japanese ships. The secret of the nimble movement lied in the flat bottom of the main body in contrast to more streamlined boats. As a result, the kobukson was able to gyrate freely.

More importantly, the firearms equipped on the kobukson were far more sophisticated and powerful that those of the Japanese naval force. With the Choson soldiers invisible behind the shield, the kobukson launched its deadly attack on the Japanese army, who were extremely scared, thinking that the fire-spouting kobukson was a sea monster.

Deadly Sea Monster

The strange appearance and destructive charging of the kobukson did much to deal a blow, both psychological and real, to the Japanese army. A Japanese soldier named Soto Oka dubbed the kobukson as a “blind boat,” suggesting its indiscriminate collision with the Japanese battleships.

Interestingly, once the Japanese naval forces came to know the kobukson better, they ran away as soon as spotting it, calculating there was no possibility in winning a battle. Unlike the widespread perception that the kobukson was utilized throughout the war, it was not used at all when the Japanese mounted another large-scale attack on the Choson in 1598. It seems the Choson naval forces also knew the kobukson lost its strategic edge against the escaping Japanese.

Another mistaken notion to be cleared up is that the kobukson was an iron-clad battleship, the first ever invention of its kind in world history. And while it still may be, historians admit the possibility that the kobukson’s cover shield could have been made of material other than iron.

There is a 17th century painting preserved in the Korea Naval Academy Museum, depicting the appearance of the iron-clad kobukson with a highly realistic touch. The painting, however, cannot be used as evidence for the existence of the iron-clad turtle ship because it greatly differs from the drawings of the kobukson in the 1795 compilation of Admiral Yi’s writings and related materials, which do not mention iron in explaining the kobukson.

Yet, there is a word meaning iron-clad armor related to the kobukson in an official letter written in 1748 by Yi Un-sup, then left naval force commander of Kyongsang province. The letter was designed to call for the construction of more kobuksons in order to replace conventional battleships.

“Although Admiral Yi’s kobukson draws keen interest from scholars, existing documents and materials are far short of public expectations. The problem is that scholars have been slow to conduct a scientific study of the kobukson, fearing it might undermine national pride and fantasy around the turtle ship,” said Lee Nam-hee, senior researcher of the Korean Studies Database Institute.