The Keicho Campaign (1597–1598) and Japanese Swords: How Toyotomi's Second Korea Invasion Impacted East Asian Sword Culture

Korean Invasions and Japanese Swords — Background of Two Campaigns

Toyotomi Hideyoshi conducted large-scale invasions of the Korean Peninsula twice: in 1592 (first year of Bunroku) and 1597 (second year of Keichō). The former is called the Bunroku Campaign, and the latter is called the Keichō Campaign. This article focuses particularly on the Keichō Campaign (1597–1598), exploring the traces this war left on the history of Japanese swords.

The Keichō Campaign was a renewed invasion following the collapse of ceasefire negotiations during the Bunroku Campaign. The Toyotomi forces mobilized over 140,000 troops, using Busan as a base to control the southern peninsula. However, with Hideyoshi's death in August 1598, the Japanese forces were forced to withdraw, and the war ended in a virtual stalemate.

Surge in Sword Demand During Wartime

The period of the Korean invasions saw the sword industry, which had matured throughout the Sengoku period, entering its final phase of mass production.

Mass Orders of Production Swords: From a logistics perspective, there was no room to equip individual samurai with high-quality custom-forged blades. Swordsmith groups centered in Bizen and Mino produced vast quantities of blades called "kazuuchi-mono" (production swords). Though individual quality varied, practical cutting performance was ensured.

Mobilization of Renowned Swordsmiths: Meanwhile, high-quality custom blades were supplied to daimyo and officer-class samurai. Some extant blades with signatures (mei) from the Keichō period bear dated inscriptions (such as "Keichō 2") reflecting the wartime demand of this period.

Japanese Swords Lost in Battle — Reality of Overseas Dispersal

Combat on the Korean Peninsula was intense, and numerous Japanese swords were left on the battlefield. The pathways of dispersal can be classified into several types.

Loss and Abandonment During Combat: Many blades were left behind on the battlefield during the withdrawal. Swords recovered by Korean and Ming forces were called "wado" (Japanese blades) and stored in Korean arsenals.

Seizure from Surrendered Troops and Captives: Swords carried by Japanese soldiers who surrendered in combat were confiscated.

Technology Transfer to Korean Swordsmith Craftsmen: Some records indicate that captured Japanese smiths were held in Korea and transferred their techniques. While records of craftsmen deported to Korea as "pottery ancestors" are famous in ceramics, similar cases are said to have occurred with blacksmiths as well.

"Wado" (Japanese Swords) Remaining in Present-Day Korea and China

Today, Korean national museums and folk museums preserve Japanese swords believed to date from the Keichō Campaign. These are classified as "wado," and some have been confirmed as works of Japanese swordsmiths.

In China as well, some Japanese swords recovered by Ming forces from combat in Korea survive and are said to be included in museum collections in Beijing and Nanjing. However, detailed research and public disclosure are limited, leaving many aspects unclear.

What the Keichō Campaign Left in the History of Sword Culture

Following the war's end, the sword industry underwent rapid change.

Collapse in Demand and Closure of Smithies: The swordsmith groups in Bizen, which had supported the mass production system, suffered devastating losses when wartime demand disappeared with the establishment of the Edo Shogunate in 1603, ushering in an "era of peace." At the same time, the Bizen and Osafune region suffered severe damage from floods in 1604 (Keichō 9), forcing many of the Osafune-school smiths to close their businesses or relocate.

Transition to the Shintō Era: From the late Keichō through the Genna period, sword styles transitioned from "koto" (old swords) to "shintō" (new swords). Some scholars argue that combat experience from the Korean invasions—particularly demands regarding cutting performance and blade shape—influenced this turning point.

Reciprocal Cultural Influence: While Japanese swords flowed out to the Korean Peninsula, many technologies and cultural items also came to Japan from Korea (ceramic technology, books, etc.). Though the influence on blades was largely unidirectional, cultural exchange overall possessed complex bilateral characteristics.

Conclusion

From the perspective of sword history, the Keichō Campaign can be positioned as "a war that accelerated the end of the koto era." The fact that vast numbers of Japanese swords dispersed overseas and remained on the Korean Peninsula and in China as "wado" demonstrates that Japanese swords constitute not merely domestic cultural property, but part of the broader cultural history of East Asia.