A chord progression is a series of chords played one after another. Because we write chords as (see chords in a key), a progression works in every key: I–V–vi–IV is G D Em C in G major and C G Am F in C major.
Pick a key and listen. Each one is strummed on the guitar, one chord per to keep it short. In a real song each chord usually lasts a or more (the 12-bar blues gives each chord a whole bar).
The ii–V–I is usually played with seventh chords in jazz (ii7–V7–Imaj7), and the 12-bar blues uses the dominant seventh on every step (I7, IV7, V7). The dominant seventh is named after the V chord, the dominant, where it naturally occurs. These are four-note chords, which we look at next in seventh chords.
A phrase is a musical sentence. Its last two chords are called a cadence, and they decide how it feels: finished, softly settled or left hanging. Three endings everyone knows:
The strongest ending: the V chord pulls back to I. Countless songs end like this. Its proper name is the perfect (or authentic) cadence.
A softer ending. Hymns sing "A-men" to it, which gave it its nickname. Its proper name is the plagal cadence.
The V chord promises home, but the music lands on vi instead, so it feels unfinished. This is the deceptive cadence.
To play a progression smoothly, choose close together, so your hand barely moves. Here are grips for one progression, picked that way, each chord shown once. Open grips come first where they fit. The shapes named after a letter (like "E shape") are the and CAGED shapes from Chords on the Guitar.
Build your own progressions in the progression tool.
Next: Seventh Chords