When you play music on the rhythm guitar that has a constant tied-triplet feel with long and short notes, it’s called a shuffle or, more specifically, an eighth-note shuffle. In this case, rather than notate the music with continuous triplets and ties, the score is simplified by using plain eighth notes, but with a special performance note that instructs you to play them all in a long/short shuffle manner.
Take a look at the example below. It appears to be plain eighth notes, but the little equation at the top left instructs you to play each pair of eighth notes as if they were a triplet with the first two parts combined into one longer note (two eighth-note triplets combined to make a quarter note).
This makes the notation less congested and easier to read. You can even count the eighth notes in a normal manner, “1 and, 2 and, 3 and, 4 and”; just keep in mind that they’re always played with a shuffle feel.
When eighth notes are not shuffled and are played in their normal, evenly spaced manner, the music feel is called straight time.
Sometimes eighth notes are stretched a bit, creating a slight long/short feel called a swing. The harder a piece swings, the more it sounds like a shuffle, but a true shuffle is metrically fixed to triplet figures.
The next example uses the shuffle rhythm along with some chord changes. The sign in every other measure instructs you to repeat the measure before it. In all, you play each chord for two measures. It works well to use alternating downstrokes and upstrokes, but you can use all downstrokes, too. The Beach Boys’ “California Girls” is set to a shuffle rhythm and features a very similar chord progression.
Next, you see a chord progression set to a shuffle rhythm that mixes quarter notes and tied eighth notes. You count it “1, 2 and, and, 4” and strum it “D DU UD,” but with a shuffle feel the whole time. You can hear the shuffle time demonstrated here. “All My Loving” by The Beatles features multiple guitar tracks, including one following the same pattern with similar chord changes, but at the rate of 154 BPM.
No discussion about shuffle rhythms would be complete without mentioning its prevalent use in blues music. This is a rhythm guitar example based on an E root with an alternating fifth and sixth. It’s very reminiscent of the Grateful Dead’s “Truckin’” and many other shuffle-based, blues songs.
Shuffles are fairly common in popular music. A few more examples include “Hound Dog” by Elvis Presley, “Think It Over” by Buddy Holly, “Don’t Stop” by Fleetwood Mac, “Fool in the Rain” by Led Zeppelin, “Hide Away” by Freddie King, “Cold Shot” by Stevie Ray Vaughan, and “Roadhouse Blues” by The Doors.
It’s possible to play a sixteenth-note shuffle as well. In this case, each eighth note is split into three. In the same way that you can think of regular sixteenths as being twice the rate of eighths, you can think of a sixteenth-note shuffle as an eighth-note shuffle at twice the rate, playing the sixteenths with the same kind of lilting feel that shuffled eighths have. A few examples include Toto’s “Rosanna” and Bob Marley’s “Stir It Up.”