Bunroku Campaign (First Korean Invasion)

The Bunroku Campaign and the First Large-Scale International War for the Japanese Sword

In April of Bunroku 1 (1592), after achieving domestic unification, Toyotomi Hideyoshi—seeking to fulfill his ambition of continental conquest—dispatched a massive force of approximately 158,000 men to the Korean Peninsula. The "Bunroku Campaign" (1592–1598), the first of "the Bunroku and Keichō Campaigns," was not only the largest overseas military expedition in Japanese history, but also the first war in which Japanese swords were deployed on an international stage on a large scale.

The vanguard units under Katō Kiyomasa and Konishi Yukinaga advanced with lightning speed from Busan to Seoul (Hanseong), and further to Pyongyang. However, the Korean navy centered on Admiral Yi Sun-sin's turtle ships (geobukseon) threatened the Japanese supply lines, and a Ming relief force counterattacked to retake Pyongyang. Despite maintaining superiority on land, the Japanese forces were forced to withdraw due to supply difficulties, and the conflict shifted to ceasefire negotiations.

Hideyoshi's Ambition: Why He Sought Continental Conquest

Historians debate Hideyoshi's motivation for the invasion of Korea on several grounds.

First, the "continental conquest ambition" theory—after unifying Japan, Hideyoshi aimed at the conquest of Ming China, positioning Korea as a pathway to that goal. This vision, called the "invasion of the Tang" (唐入り), was Hideyoshi's dream in his final years.

Second, the "problem of accommodating Sengoku warriors" theory—after unification, redirecting the military power of warriors who had lost their battlefields overseas was intended to suppress discontent and prevent rebellion within Japan.

Third, the "hegemony over East Asian trade" theory—seeking the center of the developing East Asian trade in Korea and Ming China, this view emphasizes economic motives to control those interests.

Each theory carries some persuasiveness, and scholarly debate on the full scope of Hideyoshi's motives continues to this day.

Katō Kiyomasa and the "Tiger Hunt": A Hero Tale of the Bunroku Campaign

One of the most famous anecdotes of the Bunroku Campaign is the "tiger hunt" (虎狩り) by Katō Kiyomasa. According to legend, Kiyomasa advanced into Hamgyong Province and slew a Korean tiger with his spear. The spear said to have been used when Kiyomasa killed the tiger—a Japanese spear—and the tiger pelt said to have been brought back as a trophy became symbols of Kiyomasa's feats of valor.

Katō Kiyomasa was known for his distinctive helmet with the "serpent's eye" (蛇の目) emblem and its large eboshi-shaped crest, and his imposing figure was depicted in numerous paintings and woodblock prints (ukiyo-e). Many legends surrounding Kiyomasa's swords and spears remain in Higo (present-day Kumamoto Prefecture), where Kiyomasa was lord. Kiyomasa's family crest, the "serpent's eye," is preserved today in the seal of Kumamoto City, and Kiyomasa continues to be revered as a "hero" of Higo.

The Japanese Sword Against Korean and Ming Weapons: Cultural Exchange and Technological Impact

The Bunroku Campaign was the first war in which Japanese swords were deployed on a large-scale international battlefield. The primary weapons of the Japanese forces were the matchlock arquebuses (火縄銃), Japanese swords, and spears. In particular, the sharpness of the Japanese blade and the skill of Japanese swordsmen in close combat left a profound impression on Korean and Ming forces.

Korean records contain frequent references to the sharpness of the "倭刀" (Japanese sword), with surviving accounts noting that "倭兵 (Japanese soldiers) are skilled in swordsmanship and cannot be approached at close range." On the other hand, the blockade of maritime supply lines by Yi Sun-sin's fleet proved to be the decisive factor that ultimately forced the militarily dominant Japanese forces to retreat.

This war affected the swordsmanship and military technology on both sides. Some research suggests that Korean swordsmanship was influenced by Japanese blade techniques following the Bunroku Campaign. Conversely, Japanese master smiths brought back the renowned Korean craftsman Kim Dosu and others to Japan, influencing Japanese ceramic and lacquerware culture (referred to as the "pottery war" due to the abduction of Korean potters). It is said that Korean metalworking and forging techniques also flowed into Japan during this period.

Nagoya Castle (Nagoyajō in Hizen): The Base of Operations for the Korean Expedition

The launching point for the Japanese forces in the Bunroku Campaign was Nagoya Castle (名護屋城), constructed in Nagoya, Hizen Province (present-day Karatsu, Saga Prefecture). In April of Bunroku 1 (1592), Hideyoshi traveled to Nagoya, and daimyo from throughout the realm assembled around the massive fortress.

More than 130 daimyo residences stood in the vicinity of Nagoya Castle, and this military and administrative concentration was called "a second Osaka." The gathering of famous swords brought by each daimyo to Nagoya represented a major concentration point of Sengoku sword culture.

The Historical Significance of the Bunroku Campaign: The "International Debut" of the Japanese Sword

The Bunroku Campaign holds a special place in the history of the Japanese sword as the first war in which Japanese blades made a significant presence on a truly international stage. In close combat on land, the swordsmanship of Japanese soldiers and the sharpness of Japanese swords made an overwhelming impression on Korean and Ming forces. This experience, coupled with the name "倭刀" (Japanese sword), spread throughout East Asia, marking the moment when the Japanese sword established its international "brand."

At the same time, the Bunroku Campaign foreshadowed the "beginning of the end" for the age of the sword. In battles against Korean and Ming forces, firearms (arquebuses and cannons) played an important role, and Japanese arquebusier units contributed significantly to the assault on Korean fortifications. The modernization trend from "sword to gun" is evident in this campaign as well.

The seven-year Korean expeditions (Bunroku and Keichō Campaigns) brought enormous military and fiscal burdens on the Toyotomi regime and became one of the remote causes of the regime's collapse after Hideyoshi's death (1598). The rivalries among the daimyo generated by this "reckless" Korean invasion are deeply embedded in the background of the Battle of Sekigahara (1600).