A minor
A minor key with no key signature; relative minor of C major.
What it means
A minor is the minor key whose natural scale is built on the root A: A–B–C–D–E–F–G–A. It uses only the white keys of the piano and therefore requires no key signature.
Its relative major, the major key sharing the same key signature, is C major. Both keys share the same pitch collection but differ in tonic and character: A minor sounds darker and more introspective than the bright C major.
In the notation
A minor is notated without a key signature, just like C major. In practice, however, individual notes are frequently altered with accidentals: in the harmonic minor scale the seventh degree (G) is raised to G♯, and in the melodic minor scale the sixth degree (F) is additionally raised to F♯, in each case only in the ascending direction.
Musical use
As the minor key with no sharps or flats, A minor is often the first minor key learners encounter on piano or guitar, since it connects directly to C major. It is frequently regarded as a serious, plaintive, or melancholic key and appears in many well-known works for tragic or reflective passages.
Well-known examples include numerous folk songs and compositions built around the open A string of string instruments.
Performance practice
Practice the natural A minor scale over two octaves before adding the harmonic and melodic forms. Pay particular attention to the characteristic augmented second between F and G♯ in the harmonic minor scale, which feels technically different from the even whole- and half-step motion of the major scale, and intonate the raised leading tone G♯ deliberately close to A.