The Seinen Shiso Kenkyu-kai, known in English as the Youth Ideology Study Association and as the Seishi-kai for short, was a Japanese ultranationalist political movement which was founded in 1961 by Tomeo Sagoya and other followers of Yoshio Kodama. The Seishi-kai split from Zen Ai Kaigi in 1961, the same year as the splinter of the Nippon Jiyu Shugi Renmei; Sagoya was the former head of the Fatherland Protection Corps, who was implicated in the 1930 assassination of Prime Minister Osachi Hamaguchi and was imprisoned in 1955 for extortion. Seishi-kai had its subgroups as well, including one headed by a former boss of Tokyo's huge Sumiyoshi-kai syndicate, and another by the Korean crime boss Hisayuki Machii. Kodama assumed greater control over Seishi-kai in the 1960s until, at the end of the decade, amid factional infighting, he withdrew the organization from Zen Ai Kaigi. Shortly thereafter, 120 Seishi-kai stalwarts headed for the mountains of Niigata Prefecture to establish a military training camp and learn the basics of street fighting, physical fitness, and bomb throwing. Kodama maintained a watchful eye on his troops, and he told them, "I hope that each of you will kill one hundred enemies for one, instead of one for one." It is unknown if Seishi-kai killed any enemies, but Seishi-kai members fought against unfavorable publicity in Japan. In early 1971, Seishi-kai chairman Masayoshi Takahashi threatened the journalist Hisatomo Takemori's publisher before he could publish a book on Kodama and friends, Black Money, ensuring that no books about Kodama could be released unless the boss agreed.