Asahi Shimbun, a Japanese newspaper, sponsors the first National High School Baseball Championship. It is an instant success and will continue every August (except during World War II) to the present. It will often be called the Koshien Tournament, after the stadium near Osaka where the games will be played starting in 1924.

This Day In Baseball

On August 18, 1915 — Asahi Shimbun, a Japanese newspaper, sponsors the first National High School Baseball Championship. It is an instant success and will continue every August (except during World War II) to the present. It will often be called the Koshien Tournament, after the stadium near Osaka where the games will be played starting in 1924.

Source:
Baseball Reference August 18
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