From May 22, 1948 to October 13, 1958, multiple charts were published, which explains the overlap in the dates of the charts. Previously,
Harlem Hit Parade, created in 1942, had listed the “most popular records in Harlem" and another chart, "Race Records Juke Box", was created in 1945; in 1948, a parallel chart was added: "Race Record Best Sellers". (The term "
race music" originally came from within the black community, but was deemed offensive in the postwar world.) All of these were renamed as R&B charts in 1949. A third, "Jockeys" chart, based on radio airplay, was introduced in 1955, and a unified chart was only introduced in 1958. Because of the existence of multiple charts, some dates had more than one number-one song during the week. ==Gap in the chart==