Chord category
Extended chords
Extended chords stack thirds beyond the seventh: the ninth, eleventh and thirteenth. They are the foundation of jazz and bossa colour.
Theory
C9 is a C7 plus the ninth. Continuing upward you reach the eleventh (C11) and thirteenth (C13).
Formula and steps
Degrees
1 – 3 – 5 – ♭7 – 9
Steps (semitones)
4 – 3 – 3 – 4
How they are used
They add richness and sophistication. Because they have so many notes, some are often omitted (the fifth or eleventh) and the rest spread across both hands.
Progressions (roman numerals)
- ii9 – V9 – Imaj9
- Imaj9 – VI9 – ii9 – V9
Example sequences
- Dm9 – G9 – Cmaj9
- Cmaj9 – A9 – Dm9 – G9