The 12-Bar Blues

The 12-bar blues is the most-played form in popular music, and it is small enough to memorise on the spot. Twelve bars, three chords, three lines of four bars each: I · I · I · I, then IV · IV · I · I, then V · IV · I · V. In A that is four bars of A, two of D, two of A, then E–D–A–E. The final bar of V is the turnaround: instead of resting on home, it leans on the tensest chord in the key so the ear demands bar one again — the form resets itself. The full changes in every key live on the twelve-bar blues progression page, and the number system from the beginner path moves it anywhere.

Feel matters as much as the changes. Straight eighths split each beat exactly in half — "1-&-2-&", even and driving. A shuffle swings them: hear each beat as a triplet and strum only its first and last note — long-short, long-short, "1-trip-let". Same chords, completely different groove, and that lopsided feel is the one most blues (and early rock and roll) rides on. The blues style guide goes deeper on the feel and the players to steal from.

Now play it: the 12-bar blues routine below runs a condensed form with plain A, D, and E triads first, so you can concentrate on the changes — and, as its own tip says, the upgrade is swapping each chord for its seventh (A7, D7, E7) once the changes are automatic. Those are the dominant 7ths from step 3, and they give the blues its growl.

Practice this