Power chord
A power chord (or fifth chord, written with the suffix "5", e.g. E5) contains only two different notes: the root and its fifth, sometimes doubled with an octave. Unlike a full chord, it has no third — and that absence is exactly what defines it: a power chord sounds neither major nor minor, it's harmonically neutral.
That neutrality is why the power chord became the backbone of rock, punk and metal, especially under distortion: without a third, the chord doesn't produce the harsh clashing harmonics that distortion exaggerates on a full chord.
A consequence rarely explained elsewhere: power chords work with either scale
Because it commits to neither major nor minor, the same power-chord riff can be improvised over with a minor pentatonic scale or its relative major, with no clash from the third. That's exactly the principle behind Guitarshelf's "metal" improvisation sheets: the minor pentatonic sits on top of the power-chord riff with zero conflict, where it would clash against a full major chord.
Guitarshelf's power chords library shows the movable shape across all 12 keys, and the power riff sheet type offers full ready-to-play sequences.
Practical tips and common mistakes
- Always mute the strings you're not using, especially neighboring low strings: that's the most common cause of a power chord sounding "dirty," far more often than a bad fingering.
- The "5" in E5, A5, and so on refers to the fifth interval, not a fret number — a common beginner mix-up that sends people looking for the 5th fret.
- Never add a third string thinking it enriches the chord: the missing third is exactly what defines a power chord — one more string turns it into a full chord, with the major or minor character a power chord specifically avoids.
- Practice sliding the same shape along the neck rather than memorizing each key separately: a power chord is a movable shape, the starting fret alone changes the key, nothing else.