In the conduct of prewar Japanese foreign relations, political associations (seiji kessha) – we might also call them pressure groups – exerted considerable political influence, particularly on Japan's relations with China and other Asian nations. One of the best known of these political associations is the Kokuryūkai (the “Amur Society,” also known as the “Black Dragon Society”), which was founded in 1901 and, in 1946, was banned as an ultranationalist association by the American occupation authorities. The Kokuryūkai was also identified as the center of an expansionist conspiracy to steer Japan towards war with the Western powers.

In the absence of detailed studies of the Kokuryūkai, this article aims to clarify the organization's political views and activities and to demonstrate its influence on Japanese foreign relations and involvement in East Asia in the early twentieth century. Drawing on primary sources such as the association's publications and its leaders' memoranda and letters, I show that the Kokuryūkai engaged in intensive networking activities and the accumulation of social capital involving not only Japanese but also Chinese and Korean politicians and diplomats. Nevertheless, I conclude that the association's influence on the origins of the Asia-Pacific War should not be overstated, since its activities reached a climax in the late 1910s and effectively ended with the death of founder Uchida Ryōhei in 1937.