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.
C#13 is C#, E#, G#, B, D# and A# — C#9 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.

| C# | E# | G# | B | D# | A# |
|---|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | 9 | 13 |
Dominant — the full V chord.
Also written C#dom13 or C# 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.
C#13 has 1 of them, only on strings 6-4-3-2, all of them at the 3rd fret — all in one inversion, so the bass note never moves. The one to learn first is the A# shape at the 3rd fret.
Start with x43302 — no barre and 1 open string. 1 of the 8 shapes here sits in open position. 6 of the 8 need a barre. Together they cover the neck from the 2nd fret to the 11th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x43302 | open position | C#, root position | Gb | 1 open string |
| x43466 | 3rd fret | C#, root position | A# | all fretted |
| x43446 | 3rd fret | C#, root position | A# | barred |
| 444466 | 4th fret | G#, 2nd inversion | A# | barred |
| 968667 | 6th fret | C#, root position | B | barred |
| 988897 | 7th fret | C#, root position | B | barred |
| 9-9-9-10-11-11 | 9th fret | C#, root position | D# | barred |
| 9-11-9-10-11-9 | 9th fret | C#, root position | C# | barred |
The same notes rebuilt from scratch give 2 shell, 13 drop 2, 9 drop 3 and 25 rootless voicings, each on its own page.
Tensions. A shell of C#13, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (F##).
C#13 is the V of F#, 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 F#.
Voice by voice, C#13 → F#. 2 voices move by a semitone, and 2 notes are common to both chords.
| In C#13 | Moves | In F# |
|---|---|---|
| C#, the root | stays where it is | C#, the fifth |
| E#, the major third | rises a semitone | F#, the root |
| G#, the fifth | falls a whole tone | F#, the root |
| B, the flat seventh | falls a semitone | A#, the major third |
| D#, the ninth | falls a whole tone | C#, the fifth |
| A#, the thirteenth | stays where it is | A#, the major third |
In which keys. Every note of C#13 belongs to Eb minor (the ♭VII) and F# major (the V, the dominant).
Every note of C#13 is in C# mixolydian and C# lydian dominant.
Change one note of C#13 and you have C#maj13 (the flat seventh becomes a major seventh), C#69 (drop the flat seventh), C#9 (drop the sixth) or C#9#11 (the sixth becomes a flat fifth).
C#13 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On C#13’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.