Blues is a foundational American music genre that emerged among African‑American communities in the Deep South during the late 19th century. It’s built around a cyclical I–IV–V chord progression—most famously the 12‑bar blues form—and features “blue” notes (flattened 3rds, 5ths, and 7ths), swung rhythms, and a call‑and‑response structure between vocals and instruments. Lyrically, blues songs often express personal hardship, longing, and resilience, giving voice to life’s struggles. Instrumentation typically includes guitar (acoustic, electric, and slide), harmonica, piano, upright bass, and drums. From its earliest rural Delta styles to electrified urban variants like Chicago blues, the blues has profoundly influenced jazz, R&B, rock ’n’ roll, and virtually every strand of modern popular music.