A Half-Diminished — Complete Guitar Arpeggio Guide Overview A Half-Diminished is a seventh arpeggio containing 4 notes: A, C, Eb, G. The formula 1-b3-b5-b7 defines its interval structure. Dark, sophisticated — the ii chord in minor ii-V-i. This arpeggio belongs to the tense, unstable diminished family and is commonly used in Jazz, Classical, Film Score music. Music Theory The A Half-Diminished arpeggio uses the intervals Root (1), Minor Third (b3), Tritone (b5/#4), Minor Seventh (b7). Starting from A, each note is a specific interval above the previous degree. The A Half-Diminished arpeggio is constructed using the interval formula 1-b3-b5-b7, which means it contains the intervals Root (1), Minor Third (b3), Tritone (b5/#4), Minor Seventh (b7) above the root A. The notes are A, C, Eb, G. An arpeggio differs from a scale in that it uses only the chord tones — the notes of the underlying chord played sequentially rather than simultaneously. The diminished arpeggio stacks minor thirds, creating maximum tension. Key characteristics: Jazz, Classical, Film Score. Sound & Character A Half-Diminished sounds tense, unstable, and angular. The symmetrical interval pattern creates a disorienting quality that strongly demands resolution. The emotional feeling is anxious, suspenseful, and unsettling. Used in jazz for complex harmonic exploration and in classical music for dramatic tension. Musical Applications A Half-Diminished is most commonly found in Jazz, Classical, Film Score music. This advanced arpeggio opens up sophisticated harmonic possibilities. Common uses include outlining iiø7 and creating melodic lines. Practice Recommendations Start with 5-minute sessions playing each note slowly and cleanly. Gradually increase to 10-minute metronome exercises, then 20-minute improvisation sessions. At 30 minutes, explore multiple fretboard positions and connect them smoothly. Record your practice to identify areas for improvement.