Busan’s role as a transit corridor linking colonial Taiwan, Japan, and Korea

The colonial networks that Japan built across Northeast Asia between 1895 and 1945 did not function through administrative intention alone. They required physical infrastructure, such as ports capable of handling industrial volumes of cargo.

This included rail lines connecting interior agricultural regions to coastal terminals, shipping routes disciplined enough to move people and goods on predictable schedules, and the bureaucratic machinery to coordinate movement across territories that spanned thousands of miles of ocean and continent.

Busan, positioned at the southeastern tip of the Korean peninsula where the Korea Strait narrows toward the Japanese home islands, occupied a specific position in that network as a primary transit point connecting Japan to its colonial territories on the continent and, through the broader maritime system, to Taiwan.

The geography that made Busan central to the colonial network was not created by empire. It was organized by it. The Korea Strait at its narrowest point between Busan and Shimonoseki is approximately 200 kilometers wide. That crossing was the primary maritime link between Japan and the Asian continent throughout the colonial period.

The distance is short enough to be navigated reliably in all but the worst weather conditions, and deep enough to accommodate the commercial and military vessels that the colonial economy required. Everything moving between Japan and Korea — administrators, soldiers, laborers, agricultural products, manufactured goods — passed through that corridor.

Busan was the Korean end of the crossing, the point where the maritime route from Japan met the land-based infrastructure that extended north through the Korean peninsula toward Manchuria and the Chinese interior.

The Kampu Ferry service, which connected Busan to Shimonoseki beginning in 1905, formalized the crossing as a scheduled and managed operation within the colonial transportation system. The service ran continuously through the colonial period, and what it carried reflected the full range of the empire’s human and commercial traffic.

Colonial administrators traveled the route in both directions as postings were filled and rotated. Military personnel moved through it as strategic requirements shifted. Migrant workers, Korean laborers recruited or conscripted for industrial and agricultural work in Japan, crossed in large numbers during periods of peak labor demand. Students from Korea and other parts of the empire traveled the route toward Japanese universities.

Commercial cargo moved in both directions, with Korean rice and other agricultural products heading toward Japan, with Japanese-manufactured goods and capital equipment moving in return. The ferry route was not incidental infrastructure built to supplement other connections. It was the primary physical link between Japan’s home islands and its largest and most integrated colonial territory.

Taiwan’s connection to the colonial network operated through a different mechanism. The island’s relationship to the broader imperial system ran primarily through maritime shipping rather than the land-based rail infrastructure that connected Korea to Manchuria and the Chinese interior.

Taiwanese agricultural exports essential to the imperial economy, like sugar, rice, and camphor, moved north from Keelung, the island’s primary colonial-era port, on Osaka Shosen vessels that stopped at Moji/Shimonoseki on the northern Kyushu coast, before continuing to Busan and then to Dаіrеn on the Manchurian coast. Moji/Shimonoseki functioned as the maritime hub where Taiwan’s northbound cargo and passenger traffic entered the continental corridor.

In a single month during the Taisho era, 60 passenger ships departed Moji/Shimonoseki for destinations spanning Korea, China, India, and Europe. The Osaka Shosen network tied Keelung, Moji/Shimonoseki, Busan, and Dаіrеn into a single connected system. That meant a passenger boarding at Keelung could reach Dаіrеn without leaving the same shipping company’s network.

Busan functioned within this larger system as a waypoint and intersection, the center where a continental portion of the colonial network, running north through Korea toward Manchuria, met the maritime routes that connected Japan to Taiwan and the broader Pacific. The three territories were not linked in a simple triangle. They were connected through a hub-and-spoke system centered on Japan’s home islands, with Busan serving as the critical transfer point where the continental and maritime portions of the network converged.

The crossing processed that human traffic continuously throughout the colonial period, in volumes that reflected the scale of an empire managing millions of people across a wide arc of Asia. The physical infrastructure that made Busan central to the colonial network was built in phases that reflected the empire’s expanding ambitions. The port facilities that existed at Busan before the Japanese annexation of Korea in 1910 were developed and expanded under Japanese administration into one of the most significant cargo handling operations in Northeast Asia.

Railway connections from Busan north through the Korean peninsula to the Manchurian border, and onward through Manchuria to the Chinese interior, were completed and extended across the colonial period, creating a continuous route from the Shimonoseki strait to the borders of the Soviet Union. The combination of the maritime crossing from Japan and the rail network extending north from Busan produced a transportation spine that the colonial economy ran along for four decades.

The Korean War transformed the corridor’s function. When North Korean forces crossed the 38th parallel on June 25, 1950, and drove south with speed that compressed the Republic of Korea’s defensive perimeter to a small area around Busan in the southeast, the city became something it had not been during the colonial period. It was the last point of defense rather than a point of transit.

The Busan Perimeter, held from August to September 1950, was the geographic boundary within which the Republic of Korea and United Nations forces consolidated before the Inchon landing reversed the war’s momentum. The port that had spent decades moving colonial traffic in both directions became the entry point through which American and allied forces supplied and reinforced a desperate defense. That transformation sits at the hinge between two histories. Between the colonial network that built the port, and the war that could have ended Taiwan’s isolation from the world it had been severed from in 1895.

The port of Busan itself did not change. The water between it and Shimonoseki is the same 200 kilometers it has always been. What changed was who needed the crossing and why. The same port that moved Korean laborers toward Japanese factories and Taiwanese sugar toward Japanese markets spent two months in 1950 as the last open door on the peninsula.

Had the perimeter broken, the invasion by Soviet-backed North Korea would have ended differently. A unified communist Korea had the power to change the military geography of the western Pacific, including Taiwan, already dependent on American commitment that had not yet hardened into policy. The Busan Perimeter held, and with it, the military geography that kept Taiwan’s future an open question rather than a hard conclusion.