maj9

A maj9 chord, also written maj9 or M9, is a major seventh chord extended by a ninth. It contains the root, a major third, a perfect fifth, a major seventh, and a major ninth above the root. In integer intervals, the chord comprises 0, 4, 7, 11, and 14 semitones from the root.

Notation and naming: common spellings include Cmaj9, CM9, or CΔ9 (Delta denotes major seventh). The ninth is the note a whole step above the root an octave higher, yielding a colorfully extended major sound without requiring alterations to the triad’s basic quality.

Voicing and construction: in practice, players may voice a maj9 with or without the fifth. A typical piano voicing places the root, major third, and major seventh in proximity, then adds the ninth, while the fifth may be omitted to reduce clutter. On guitar, common shapes emphasize the seventh and ninth to preserve the characteristic color, again sometimes omitting the fifth. Because the ninth can clash with other tones in certain textures, some voicings omit or redistribute notes to achieve a smooth balance.

Usage and function: maj9 chords are widely used in jazz and contemporary music for a lush, open color that enhances major harmony. They are common as tonic colors or as enriched variants of maj7 chords, adding brightness and a sense of forwards motion without implying dominant function.