Classic Chord Progressions in Songs by the Beatles
The most important chords in any key are the I and V chords, and in rock music, the IV chord is close behind. The V chord creates a sense of tension that pulls your ear back to the I chord, so you’ll often hear that chord played before a progression returns to the I, as in Example 3 (where the V chord leads back to I on each repeat). You’ve probably heard this chord progression countless times; it’s similar to the one in the Beatles’ version of “Twist and Shout.” We call it a I–IV–V (“one–four–five”) progression, following the Roman numerals assigned to each chord.
Another popular progression is I–vi–ii–V (“one–six–two–five”), which you’ll find in songs like the Beatles “That Boy” and “Yes It Is” (Example 4).
Excerpted from Acoustic Rock Essentials