Many people played by EAR and did NOT read actual notated music. ... Jazz... C - E - G - Bb ... omitting the root, letting the bass guitar play the 5th and all you play is the discordant tri-tone. ... In AMERICA, my guess is you need to look through all the music. ... 1890 with ragtime, then 1900 folk blues & classical jazz. 1920 had hot jazz, boogie blues and chicago style. 1930 depression brought in swing & classic blues & gypsy jazz. 1940 began the Be-Bop rhythm and the blues vocalese. 1950 brought us to mainstream jazz, but it's all about KNOWING YOUR SCALES.