B♯7♭9 Chord: Guitar, Piano and Notes
The B♯7♭9 chord is a altered dominant seventh chord built on the root note B♯. Its notes are B♯, D𝄪, F𝄪, A♯ and C♯. It's enharmonically the same chord as C7♭9.
Dominant seventh flat nine chords sound dark and urgent. Stacking a minor ninth on a dominant seventh tightens the tension already built into the tritone, which makes the chord a strong pull toward a minor tonic.
- Notes
- B♯ · D𝄪 · F𝄪 · A♯ · C♯
- Formula
- 1 · 3 · 5 · ♭7 · ♭9
- Semitones
- 0 · 4 · 7 · 10 · 13
- Note
- B♯
- Quality
- Dominant 7♭9
- Symbol
- B♯7♭9
B♯7♭9 on piano
5 notes
Switch to the interactive diagram to hear the chord, change voicing and swap finger numbers for note names.
To play B♯7♭9 on piano, place your right hand with your thumb on B♯, index finger on D𝄪, middle finger on F𝄪, ring finger on A♯ and little finger on C♯. Press the keys together and listen for an even sound. On the keyboard A♯ and C♯ are black keys and B♯, D𝄪 and F𝄪 are white, the keys you'd normally call C, E and G. Practice moving in and out of the chord slowly, then bring in a metronome.
- B♯1
- D𝄪3
- F𝄪5
- A♯♭7
- C♯♭9
B♯7♭9 on guitar

Switch to the interactive diagram to hear the chord, change voicing and swap finger numbers for note names.
On guitar, B♯7♭9 is commonly played with the voicing shown above. This one is a barre at fret 2: keep the index finger flat across the strings and curve the others so they don't mute the strings next to them. Don't play string 6.
B♯ · D𝄪 · F𝄪 · A♯ · C♯
Play B♯7♭9 on the online piano
Free, in your browser: play with the mouse, your computer keyboard or a USB MIDI keyboard. No sign-up.
B♯7♭9 chord notes
Also known as C7♭9
| Degree | Interval | Semitones | Note | Hear |
|---|---|---|---|---|
| 1 | Root | 0 | B♯(B#) | |
| 3 | Major third | 4 | D𝄪(D##) | |
| 5 | Perfect fifth | 7 | F𝄪(F##) | |
| ♭7 | Minor seventh | 10 | A♯(A#) | |
| ♭9 | Minor ninth | 13 | C♯(C#) |
How to use the B♯7♭9 chord
The B♯7♭9 chord is built from a root, a major third, a perfect fifth, a minor seventh and a minor ninth. Start at the root B♯ and stack the intervals to get the whole chord: B♯, D𝄪, F𝄪, A♯ and C♯. The same formula gives you the chord in any other key.
Dominant seventh flat nine chords are the classic altered dominant of bebop and gospel, most often the V7 of a ii-V-i in a minor key. Gospel piano voices this chord thick under the vocal line right before it resolves.
How B♯7♭9 differs from similar chords
B♯7♭9 is B♯7 with a minor ninth, a half step above the root, where B♯9 has a major ninth. Leave out the root and the other four notes form a diminished seventh chord a major third up. That is why it pulls so hard towards a minor chord a fifth below.
Where B♯7♭9 is used
No progression is shown for this spelling
Every key B♯7♭9 would have a function in has a tonic that needs a double accidental, which is not a key this library teaches. The enharmonic spelling carries the same chord in a key that exists.
Questions people ask
- What notes are in the B♯7♭9 chord?
- The B♯7♭9 chord contains B♯, D𝄪, F𝄪, A♯ and C♯ (B#, D##, F##, A# and C# in plain text).
- Is the B♯7♭9 chord major or minor?
- B♯7♭9 is a altered dominant seventh chord. Dominant seventh flat nine chords sound dark and urgent. Stacking a minor ninth on a dominant seventh tightens the tension already built into the tritone, which makes the chord a strong pull toward a minor tonic.
- How do you play B♯7♭9 on piano?
- Place your fingers on B♯, D𝄪, F𝄪, A♯ and C♯ and play them together. The root usually goes to the little finger of the left hand, the upper notes to the right. On the keyboard A♯ and C♯ are black keys and B♯, D𝄪 and F𝄪 are white, the keys you'd normally call C, E and G.
- How do you play B♯7♭9 on guitar?
- Use the fingering in the diagram above. This one is a barre at fret 2: keep the index finger flat across the strings and curve the others so they don't mute the strings next to them. Don't play string 6.
- What is another name for the B♯7♭9 chord?
- B♯7♭9 is enharmonically equivalent to C7♭9. Both chord names describe exactly the same notes, but the spelling depends on the key you are playing in.