What is the significance of the '12-bar blues'?

The '12-bar blues' is significant because it serves as a foundational chord progression within blues music. This structure is characterized by a specific pattern of chords that typically follows a I-IV-V progression over twelve measures. This form allows musicians to improvise and express themselves within a defined framework, making it a staple in blues and influencing various genres, such as rock and jazz.

The distinguishing feature of the 12-bar blues is its predictable pattern, which helps both musicians and listeners establish a common ground in terms of musical structure. This progression provides a sense of stability and familiarity, encouraging improvisation and lyrical storytelling, which are central to the blues tradition. The repetitive nature of the 12-bar form also enables performers to experiment creatively, making it a fundamental aspect of many blues compositions.

In contrast to classical compositions, which often have more complex structures, or jazz, where improvisation may follow different formats, the 12-bar blues stands out as a straightforward and accessible musical framework. It is not a drum pattern, but rather a progression applied to various instruments, often featuring guitar or piano alongside vocal lines. Thus, its role as a common chord progression in blues music underlines its significance in the development of modern musical forms.