Before you can exploit the I to IV movement, you need to know exactly what it is and where to find it in the blues form. This short lesson maps out the harmonic landscape so every other lesson in the course makes immediate sense.
What you’ll get out of this lesson: A clear understanding of the I to IV progression — what the two chords are, how they relate, and precisely where the change occurs within a standard 12-bar blues.
The I and the IV in context
In blues, the I chord is your home base — the tonic. The IV chord is built on the fourth degree of the same key. In the key of G, for example, the I chord is G7 and the IV chord is C7. That shift from G7 to C7 is one of the most characteristic sounds in all of blues music, and it happens twice in a standard 12-bar form.
Where the change falls in the 12-bar form
In a standard 12-bar blues, the first move to the IV chord happens at bar 5, and there is often an anticipation of the change in the second half of bar 4. The I chord returns at bar 7. Understanding these exact locations gives you a target to aim at when you are practising ways of outlining or anticipating the change — every technique in this course is designed to make that specific moment more musical and expressive.
Taking it further: Listen to a handful of blues recordings and count through the 12 bars, locating the I-to-IV move each time. Notice how different players handle bars 4 and 5 — some anticipate the change early, others land squarely on it. That variety is exactly what this course explores.
Your homework: Play through a 12-bar blues in one key slowly, calling out “I” and “IV” out loud as you hit each chord. Then loop bars 4 and 5 specifically and get comfortable sitting on the I chord right up to the change. This awareness of where the change is will make every subsequent lesson click into place faster.