The root left to the bass player. Frees a finger for a tension.
Bb13 is Bb, D, F, Ab, C and G — Bb9 with the thirteenth added on top.
It sounds big and open. Six notes will not fit under four fingers: the fifth goes first, then the ninth, and the third, flat seventh and thirteenth stay.

| Bb | D | F | Ab | C | G |
|---|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | 9 | 13 |
Dominant — the full V chord.
Also written Bbdom13 or Bb dominant 13. The same chord either way; which spelling you meet depends on who wrote the chart.
Leave the root to the bass player. In a band nobody misses it, and the ear supplies it from the guide tones anyway.
The finger it frees goes to a tension, which is why these sound richer than the shape they came from rather than thinner.
Bb13 has 26 of them, on the top four strings, the middle four strings and strings 5-3-2-1, from open position up to the 13th — every inversion the chord has: D in the bass, F in the bass, Ab in the bass, C in the bass and G in the bass. The one to learn first is the D shape at the nut, which is the easiest grip here.
9 of them sit on the top four strings, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with x10133 — no barre and 1 open string. 2 of the 10 shapes here sit in open position. 7 of the 10 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x10133 | open position | Bb, root position | G | 1 open string |
| 111133 | 1st fret | F, 2nd inversion | G | barred |
| 635334 | 3rd fret | Bb, root position | Ab | barred |
| 650044 | open position | Bb, root position | Ab | 2 open strings |
| 655564 | 4th fret | Bb, root position | Ab | barred |
| 666788 | 6th fret | Bb, root position | C | barred |
| 686786 | 6th fret | Bb, root position | Bb | barred |
| x-13-12-13-15-15 | 12th fret | Bb, root position | G | all fretted |
| x-13-12-13-13-15 | 12th fret | Bb, root position | G | barred |
| 13-13-13-13-15-15 | 13th fret | F, 2nd inversion | G | barred |
The same notes rebuilt from scratch give 3 shell, 13 drop 2, 9 drop 3 and 4 open string voicings, each on its own page.
Tensions. A shell of Bb13, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (E).
Bb13 is the V of Eb, and that is where it goes if it goes anywhere: the third and the flat seventh are a tritone apart, and both resolve by a semitone into Eb.
Voice by voice, Bb13 → Eb. 2 voices move by a semitone, and 2 notes are common to both chords.
| In Bb13 | Moves | In Eb |
|---|---|---|
| Bb, the root | stays where it is | Bb, the fifth |
| D, the major third | rises a semitone | Eb, the root |
| F, the fifth | falls a whole tone | Eb, the root |
| Ab, the flat seventh | falls a semitone | G, the major third |
| C, the ninth | falls a whole tone | Bb, the fifth |
| G, the thirteenth | stays where it is | G, the major third |
In which keys. Every note of Bb13 belongs to C minor (the ♭VII) and Eb major (the V, the dominant).
Every note of Bb13 is in Bb mixolydian and Bb lydian dominant.
Change one note of Bb13 and you have Bbmaj13 (the flat seventh becomes a major seventh), Bb69 (drop the flat seventh), Bb9 (drop the sixth) or Bb9#11 (the sixth becomes a flat fifth).
Bb13 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On Bb13’s sound and use this page follows Ted Pease & Ken Pullig, Modern Jazz Voicings (Berklee Press, 2001). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.