On May 31, 2011, the National Diet Library released the Historical Recordings Collection, sound sources contained in Japanese records such as 78-rpm records from the early 1900s to around 1950 digitized by the Historical Records Archive Promotion Conference (HiRAC) on the premises (some are also provided on the Internet). Initially, about 2,500 sources are available. Contents are to be enhanced and about 50,000 sound sources including music and speeches will eventually be provided.