Pentatonic scales

A pentatonic scale has five notes to the octave instead of seven. The two common ones are subtractions from scales you already know.

Major pentatonic

Take the major scale and remove degrees 4 and 7.

C major: C D E F G A B → C major pentatonic: C D E G A

Why those two? Because they are the notes involved in the major scale's two semitone steps — E–F and B–C. Remove F and B and no two remaining notes are a semitone apart. Nothing clashes.

Minor pentatonic

Take the natural minor and remove degrees 2 and 6.

A natural minor: A B C D E F G → A minor pentatonic: A C D E G

Same principle: the notes that produced semitone clashes are gone.

They are the same five notes

C major pentatonic is C D E G A. A minor pentatonic is A C D E G. Identical notes, different starting point — exactly the relative major and minor relationship, transferred to pentatonics.

This is why guitarists can play "the same box" over both a major and a minor progression a third apart.

Why they are so forgiving

With no semitones between adjacent scale notes, every note sits comfortably over the key's common chords. A wrong note is much harder to find, which is why pentatonics are the first thing most improvisers learn.

The trade-off is real: what makes them safe also makes them bland if that is all you use. The notes you removed are the ones that create tension and resolution, and music without tension is music without shape.

The blues scale

Add one note to the minor pentatonic — a flattened fifth — and you get the blues scale: A C D E♭ E G in A. That added note is a passing tone rather than a resting place; it is played through, not landed on.