The story
Brief history
The Kōyaren evolved from the All-Japan Secondary School Baseball Federation (全日本中等学校野球連盟 zen-nihon chutōgakkō yakyu renmei), which was formed in 1946 to oversee the National Secondary School Baseball Championship organized by Osaka Asahi Shimbun before the war.
Due to the outcome of World War II, in 1947 the school system was overhauled, and "secondary schools" became "high schools". Thus the federation was renamed to the All-Japan High School Baseball Federation.
In 1963, the federation became a private foundation separate from the Ministry of Education.
Timeline
1915.08 National Secondary School Baseball Championship first held (organized by the Osaka Asahi Shimbun)
1924.04 National Secondary School Baseball Invitational Tournament first held (organized by the Osaka Mainichi Shimbun)
1924.08 Koshien Stadium completed and becomes host to both tournaments
1946.02 All-Japan Secondary School Baseball Federation founded
1946.12 Japan Students Baseball Association becomes the parent organization
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1947.04 In accordance with the school system reform the name changes to the All-Japan High School Baseball Federation
1956.08 National High School Soft-baseball Tournament first held
1963.02 Accompanying the privatization, the name becomes the Japan High School Baseball Federation
1978.08 National High School Soft-baseball Tournament renamed to the Japan High School Soft-baseball Championship
From Wikipedia’s article on Japan High School Baseball Federation, shared under CC BY-SA 4.0.4