‘Modern blues’ covers the history of blues from after World War II. The distinction between pre–and post–war blues could be demarcated by the use of electrification and amplification of instruments. This allowed smaller bands to compete with big band sounds. America's entry into World War II caused African Americans to move to the West Coast shipyards, and form a unique, electrified sound. Billboard started using the term ‘Rhythm and Blues’ (R&B), before rock ‘n’ roll arrived on the scene. This originally hurt blues artists until the folk–blues revival and folk rock genre opened new audiences. Blues today involves mastering historical forms and embracing the African American spirit.