A major (key)

Basic characteristics

• Scale and pitch content: The A major scale follows the pattern whole–whole–half–whole–whole–whole–half and contains the pitches A, B, C♯, D, E, F♯, and G♯. See a general description of the major scale.
• Key signature: Three sharps (F♯, C♯, and G♯); summary information on key notation is available at key signature.
• Relative and closely related keys: The relative minor is F♯ minor (linked concept: relative minor); common close keys for modulation include E major, D major, and F♯ minor.
• Scale degrees: Tonic A, supertonic B, mediant C♯, subdominant D, dominant E, submediant F♯, leading-tone G♯.

Harmonic features and technical notes

A major permits straightforward diatonic harmony but also creates specific notational and harmonic situations. For example, a Neapolitan-sixth chord built on the flattened supertonic in A major will involve accidentals that introduce both a flat and a natural in the same area of the staff — a notational curiosity sometimes noted by theorists. Its dominant (E) and tonic (A) relationship is central, and secondary dominants and modulations to D or E are common.

Instrumental considerations

Strings and winds behave differently in A major. The violin benefits from open strings tuned to G, D, A, E, so A major frequently produces strong sympathetic resonance; performers and commentators have often observed that the key lies comfortably on the violin. For wind and brass instruments written in concert pitch or transposing instruments pitched in A (or with parts in A), literature in A major can exploit particular fingerings and timbres. In orchestral practice, timpani tuning for a work in A major is typically set to A and E (a fifth apart), which differs from the more common fourth-apart setting found in many other keys; historical sources and modern orchestral practice both reflect this approach. See also general notes on timpani.

History and repertoire

A major has been a favored key for a range of Classical and Romantic works. While fewer symphonies are written in A major than in certain other keys such as D major or G major, notable examples from the later repertoire include Beethoven's Seventh Symphony, Bruckner's Sixth, and Mendelssohn's Fourth. Mozart used A major effectively for clarinet literature: his well-known Clarinet Concerto and Clarinet Quintet are composed in this key, reflecting how the key relates to the sonority of the clarinet. Prominent chamber and solo works in A major include violin sonatas by composers such as Brahms, César Franck, and Gabriel Fauré, and important pianistic and violin repertoire such as Beethoven's Kreutzer Sonata is often discussed in relation to the key's effects on the instrument. Other composer references: Beethoven, Bruckner, Mendelssohn, Mozart (see also Clarinet Concerto and Clarinet Quintet).

Affective associations and commentary

Writers on musical aesthetics have long attributed characteristic moods to keys. Eighteenth- and early nineteenth-century commentators associated A major with feelings of openness, innocent love, and bright confidence; one historic description links it to youthful cheerfulness and trusting optimism. Such associations are culturally conditioned and vary by period and writer, but they help explain why composers sometimes chose keys deliberately to match a movement's expressive aims.

Practical examples and distinctions

In practice, A major is versatile: it sits comfortably for chamber groups, solo repertoire, and orchestral passages that exploit brightness without extreme brilliance. Compared with keys that use fewer accidentals, A major balances accessibility for many instruments with a slightly sharper sonority. For keyboard players the three sharps are straightforward to negotiate, while for string players the open-A and open-E strings can enhance projection. For more on theoretical concepts related to key relationships and scale construction consult introductory resources on the major scale and key theory, or specialized entries on pitch and tonic.

The key of A major thus occupies a steady place in the tonal repertoire: neither the most common symphonic key nor an exotic choice, it has produced many celebrated works and continues to be prized by performers for its sonority and practical advantages.