Nissen dōsoron

Did You Know?

• The outlines of the theory can be traced back to mid-Edo period Kokugaku scholarship, with Hirata Atsutane using studies of the Kojiki and Nihon Shoki to claim intertwined Japanese and Korean history.
• Arai Hakuseki claimed that Japanese ancestors came from the Mahan confederacy and that Kumaso might have been Goguryeo.
• The theory led to a large influx of Koreans into Japan, whose descendants became Zainichi Koreans, now the second largest ethnic minority group in Japan after Chinese immigrants.

Overview

The precursor to Nissen dōsoron was first conceived by three Japanese historians—Shigeno Yasutsugu, Kume Kunitake, and Hoshino Hisashi—in their work Kōhon kokushi gan, published before the annexation. The book asserted that legendary figures such as Susanoo, Inahi no Mikoto, and Empress Jingū had ruled or invaded ancient Silla, based on connections found in the Nihon Shoki, Shinsen Shōjiroku, and Kojiki. Susanoo was said to have first arrived in Silla, Inahi no Mikoto was claimed as an ancestor to a Silla king, and Empress Jingū was linked to Amenohiboko, a Silla prince. The Japanese scholars focused on Silla because it unified the peninsula and formed the foundation for later Korean kingdoms, allowing them to argue that Japanese origins of Silla justified a Japanese foothold in Korea's formation. These views became widely accepted in Japanese scholarship and were presented in other Meiji-era works such as Ōtori Keisuke's Chōsen kibun (1885) and Hayashi Taisuke's Chōsenshi (1892). Japanese history revisionists used the story of Susanoo to link Japanese and Korean deities, claiming that the Korean god Tan'gun was actually Susanoo, based on accounts that Susanoo first emerged in Silla at a place called Soshimori before leaving for Japan.

Influence

The theory gained momentum by comparing the Japanese and Korean ethnic groups to the sibling deities Amaterasu and Susanoo. Amaterasu was depicted as serene and patient, embodying Japanese identity, while Susanoo was portrayed as unruly and dependent on his elder sister. Susanoo had been regarded as a foreign deity from the Asian mainland since the medieval period, but was re-evaluated by Japanese historians during the annexation. His impulsive behavior was said to be inherited by Koreans, making it Japan's task to redeem them from political turmoil and cultural barbarism as an elder sibling. This contrast between Susanoo's lack of self-control and Amaterasu's serenity modeled the colonial relationship, with Korea's alleged immaturity contrasted against Japan's modernization to legitimate colonial rule. Japanese physical anthropologists also played a role in the expansion and management of colonial Korea. An ancient view that Ōkuninushi was a foreign deity from Korea was later used as justification for Nissen dōsoron, though evidence is limited to the Kojiki and Nihon Shoki listing him as a descendant of Susanoo.

Reception

They insisted that Koreans were a unitary nation in blood and culture. Following the 1938 introduction of a volunteer draft system for Koreans during the Second Sino-Japanese War, most who volunteered did so under coercion, such as threats to business licenses, or to escape discrimination and gain Japanese citizenship. In contrast, the theory enjoyed broad popular appeal in mainland Japan, offering an enlarged version of the homogeneous nation theory applied to the entire empire. Unlike pan-Asianism, the theory only included Korea in the Japanese ethnic community, not other colonies like Manchuria or Taiwan, because Korea had been in close contact with Japan throughout history. Nissen dōsoron was the main pillar supporting the related concept Naisen ittai, or unity of the inland with Korea, where the character for inland replaced the usual prefix for Japan because Korea was seen as already part of Japan.

Historical accuracy

Contemporary historians have pointed to certain accounts suggesting a close relationship between the Japanese Imperial family and the Korean peninsula. Empress Jingū's claimed conquest of Korea is linked to her descent from Amenohiboko, a prince from Silla who settled in Japan. Some theorize that Jingū was fixated on Korea due to this ancestry, though the historical accuracy of her expedition is debated. Another example is Emperor Kanmu, whose mother Takano no Niigasa was of Korean descent and deemed unfavorable as a royal consort. To counter this, Kanmu emphasized the importance of Korean culture to Japan. The Jinnō Shōtōki by Kitabatake Chikafusa mentions a record claiming Japan's origin with Korea that was lost during Kanmu's time, indicating such intentions were highly regarded. Kanmu's Korean ancestry was passed to his descendants and spread to multiple clans during the Sengoku period. This influence was officially recognized in 2001 when Emperor Akihito told reporters he felt kinship with Korea because the Chronicles of Japan record that Kanmu's mother was a descendant of King Muryeong of Baekje, marking the first time a Japanese emperor publicly acknowledged Korean blood in the imperial line.