Here’s the third secret in our power chord secrets series—and it’s one that’ll really open up your ears.
We’re talking about guitar thirds.
While power chords give you that raw, driving sound, guitar thirds add a completely different flavor. They’re still just two notes, but they create a richer harmony that’s been used in countless classic rock songs.
What Are Guitar Thirds?
A third is the interval between the root note and the third note of a scale. There are two types:
- Major third – bright, happy sounding (4 frets apart)
- Minor third – darker, more melancholic (3 frets apart)
When you play these two notes together, you get a harmony that’s fuller than a power chord but not as thick as a full chord. It’s that sweet spot that works perfectly for melodic riffs.
The Zoo by Scorpions
One of the best examples of guitar thirds in rock music is the intro to “The Zoo” by Scorpions. That haunting, melodic riff? It’s built entirely on thirds.
The song is in G major (or E minor—same notes), and the riff walks through thirds from the scale. Here’s what makes it work:
The beauty of this approach is that you’re playing two notes at a time on adjacent strings, creating that signature Scorpions sound. Rudolf Schenker knew exactly what he was doing when he wrote this one.
Brown Eyed Girl – Van Morrison
Here’s another classic that uses guitar thirds beautifully. The intro riff uses a G-C-D progression, but instead of strumming full chords, you can play it using thirds on the higher strings.
Try playing just the notes on the 2nd and 3rd strings while following the chord progression. You’ll hear those classic double-stops that make the song so recognizable.
String Position Matters
Here’s something important to know: the spacing between strings on the guitar isn’t uniform. Most string pairs are tuned a fourth apart, but the 2nd and 3rd strings (B and G) are only a major third apart.
This means:
- On most string pairs, you play thirds with a one-fret difference between the two notes
- On the 2nd and 3rd strings, you play them at the same fret for a major third
Once you understand this, you can move guitar thirds shapes around the neck and always know whether you’re playing a major or minor third.
Putting It Together
Guitar thirds are incredibly versatile. You can use them for:
- Melodic intros and riffs
- Adding harmony to a melody line
- Creating movement within a chord progression
- Building up to a full chord entrance
Combined with the other techniques from this series—power chord inversions and inverted fourths—you’ve now got a complete toolkit for creating more interesting rhythm guitar parts.
These two-note voicings might seem simple, but they’re the secret sauce behind some of the most memorable guitar parts in rock history. Now you know how to use them too.
For more on expanding your chord vocabulary, check out our complete guide to guitar chords.