An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful.
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.
An open string left ringing against a fretted grip. It costs no finger, so it can sound a note the closed shape has none left for: a tension on top, or a pedal root underneath.
These belong to their key rather than to a shape: they cannot be moved up the neck. D, A, G and E have many; E♭ has a handful.
Bb13 has 4 of them, on strings 6-4-3-2-1, the bottom four strings, the top four strings and strings 6-4-3-2, from the 3rd fret up to the 4th — every inversion the chord has: D in the bass and Ab in the bass. The one to learn first is the Ab shape at the 3rd fret, which is the easiest grip here.
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 26 rootless 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.