NHK Radio 1 (NHKラジオ第1放送, NHK Rajio Dai-ichi Hōsō) is Japan's oldest radio station operated by the public broadcaster, NHK. Its programming output, which consists of news, current affairs, and information programming is broadly similar to the BBC's Radio 4. NHK Radio 1 is available mainly on AM. The callsign is JOAK in Tokyo. It started broadcasting on March 22, 1925. During World War II, it often broadcast official announcements.