The Ionian mode (Major scale) is the foundation of Western harmony. It sounds bright, resolved, and happy. This is the "home" mode that all other modes are compared against.
Scale Formula
1 2 3 4 5 6 7 - all natural intervals. Semitone pattern: W W H W W W H
Fretboard (C Ionian)
Toggle between note names and interval labels to see how each degree sits in the shape. The root (1) is your anchor; the 3 and 7 define the major quality.
Common Chords
Major triad (1 3 5), Major 7th (1 3 5 7), Major 6th (1 3 5 6), add9 (1 2 3 5).
Diatonic Harmony
Improvisation Context
Play over major 7th and major 6th chords. The default choice for any major chord that functions as a I chord.
Characteristic Note
Ionian has no altered intervals - every degree is natural. The natural 4th is the one to watch: it clashes with the major 3rd in sustained chords, so treat it as a passing tone rather than a resting point.
Practice
Play the scale ascending and descending from any root, three notes per string. Then play only the chord tones (1 3 5 7) as an arpeggio and fill in passing tones between them. Finally, improvise over a static Cmaj7 vamp, aiming to resolve phrases on the root or the 3rd.