I7–IV7 in B♭ Major

Pattern: I7 – IV7 Chords: B♭7 – E♭7

Chord Breakdown

Numeral	Chord	Type	Function
I7	B♭7 (details)	dominant seventh	Tonic
IV7	E♭7 (details)	dominant seventh	Subdominant

Harmonic Analysis

This progression moves through B♭7 (Tonic) → E♭7 (Subdominant).

The most stripped-down blues movement: two dominant seventh chords rocking back and forth. This raw, minimal approach is the foundation of many one-chord and two-chord blues vamps.

Song Examples

Rollin' and Tumblin' — Muddy Waters
Crawling King Snake — John Lee Hooker

Chord Details

B♭7 E♭7

More Progressions in B♭ Major

I–IV–V–I I–V–vi–IV I–vi–IV–V ii–V–I I–IV–V I–♭VII–IV vi–IV–I–V I–V–vi–iii–IV–I–IV–V I–IV I–V IV–V IV–I