Blues singer and pianist, who recorded for Brunswick in 1929-1930 and for Decca in 1934.
John Oscar may have some connection with the Decca recordings by Oscar's Chicago Swingers [...] The John Oscar Trio is a pseudonym on Supertone for Charlie McCoy [i.e. Charlie McCoy (2)] and Bo Chatman. (Blues and gospel records 1890-1943 (1997), p. 694)