“Radio broadcasting began in Japan in 1925 with the establishment of stations in the three major cities of Tokyo, Osaka and Nagoya. In August of the following year, the present Broadcasting Corporation of Japan [NHK] was organized as a ‘corporate juridical person’ with the above-mentioned stations as its nuclei and was placed under the supervision of the Ministry of Communications.
“… Nowhere in the world are radio programs as rich in variety as in in Japan – in musical, dramatic and other forms of entertainment, as well as in programs of educational value … Perhaps one of the most interesting features of broadcasting in Japan is what is known as ‘radio calisthenics’. When the call is sounded from the Tokyo studios, millions of people in every corner of the land, old and young, rich and humble, almost instinctively rally around the speaker, at home, at school or at work, to join in the daily exercises designed to promote national health. For ten minutes and three times a day, these millions of health-conscious people exercise their bodies according to the instructions broadcast by the calisthenics director.
“A veritable institution in this country, radio calisthenics has made more progress and attained greater national importance than anywhere else in the world. It is one of the developments in Japan which surprised the thousand foreign delegates to the World Education Conference held in Tokyo two summers ago.”
– “Japan Calling”, Travel in Japan, Vol. 5 No. 3, 1939
“From the wiki: Although radio sets were already in use overseas and radio broadcasts were due to begin in Japan in 1925, no radio sets were being manufactured in the country. Sensing that the age of radio was about to dawn, Tokuji Hayakawa [founder of Sharp Electronics] saw his own fortunes as inextricably linked to the future of radio.
“Through efforts such as these, Japan’s first working crystal radio set was assembled in April 1925. On June 1, the JOBK radio station [now NHK (Japan Broadcasting Corporation) Osaka] made Japan’s first successful radio transmission from a test station at the illustrious Mitsukoshi Department Store. When a clear voice was picked up for the first time, the members of the development team embraced each other in celebration.”