<Li> "Mean Old World" by T - Bone Walker, recorded in 1942, is an early classic by this hugely influential guitarist, often cited as the first song in which he fully found his sound . B.B. King credits Walker as inspiring him to take up the electric guitar, but his influence extended far beyond the blues to jazz and rock and roll . Among other innovations, "Mean Old World" has a two - string guitar lick where Walker bends notes on the G string up to the notes on the B string, which would be used by Chuck Berry in "Johnny B. Goode" and other songs . </Li> <Li> "Caldonia", first recorded by Louis Jordan and then by Erskine Hawkins and others, seems to have been the first song to which the phrase "right rhythmic rock and roll music" was applied, by Billboard magazine in 1945 . Jordan, by the time of his recording of the song, was an established star, whose novelty performances had been influenced in particular by Cab Calloway . Jordan's 1944 disc, "G.I. Jive", had been the first record by a black performer to top both the pop and R&B charts . Big bands became increasingly less economically viable, and smaller groups such as Jordan's Tympany Five became more popular . Many of his recordings, including "Choo Choo Ch'Boogie" (recorded in January 1946) and "Let the Good Times Roll", were hugely influential in style and content, and popular across both black and white audiences . Their producer Milt Gabler went on to produce Bill Haley's hits, and Jordan's guitarist Carl Hogan, on such songs as "Ain't That Just Like a Woman" (also 1946), was also a direct influence on Chuck Berry's guitar style, and specifically Berry's solo in "Johnny B. Goode". </Li> <Li> "Rock Me Mamma" by Arthur "Big Boy" Crudup, recorded on December 15, 1944, was the blues singer's first and biggest R&B chart hit, but in later decades became overshadowed by his--at the time, much less successful--1946 recording of "That's All Right", later to be covered by Elvis Presley in 1954 as his first single . </Li> <Li> "Strange Things Happening Every Day" by Sister Rosetta Tharpe, recorded in 1944 with pianist Sammy Price, was a boogie - woogie flavored gospel song that "crossed over" to become a hit on the "race records" chart, the first gospel recording to do so . It featured Tharpe on an electric guitar and is considered an important precursor to rock and roll . </Li>

Describe what you believe makes rock rock and not jazz pop classical or country music