Learn › B9 Chord on Piano (B Dominant 9th)
New Released in April 2026
B9 Chord on Piano (B Dominant 9th)
The B dominant 9th chord (B9) uses the piano keys B, D#, F#, A and C#: the dominant seventh B7 plus the 9th, C#. Expect a sound that is full and bluesy-bright, tension that still sounds smooth.
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- MIDI keyboard
- Digital or acoustic piano
- Guitar
- Computer, phone or tablet
Where your hand goes for B9
Same notes, different order. Pick the position closest to the chord you just played.
Both hands: B A D# F# C#
Rootless, 3rd on the bottom: D# F# A C#
Rootless, 7th on the bottom: A C# D# F#
Left hand alone: B A
Fingering
| Left hand | B A | 5 1 |
|---|---|---|
| Right hand | D# F# C# | 1 2 4 |
B9 and D#m7b5
Above the root B sit four notes that form D#m7b5: D# F# A C#. A pianist can play B with the left hand and D#m7b5 with the right, and the result is B9.
How B9 is built
Formula 1 3 5 b7 9. Count from B and every number is a step of the B major scale, and a b lowers it by one key.
Start chord: B7
| Note | Step | Interval | Keys from B |
|---|---|---|---|
| B | 1 | root | 0 |
| D# | 3 | major 3rd | 4 |
| F# | 5 | perfect 5th | 7 |
| A | b7 | minor 7th | 10 |
| C# | 9 | major 9th | 14 |
Practise B9 in four steps
- Find B, then add the other notes one at a time: B, D#, F#, A and C#.
- Play B7, then B9, then B7 again, and hear what the 9th adds to the seventh.
- Alternate root position and a rootless shape with the 3rd on the bottom, keeping shared notes still.
- Then test it in random order among other chords: recall under time pressure is what sticks.
Five minutes a day is enough to make B9 feel easy.
When to play B9
- B9 is the V chord of E major: it pulls home to E.
- Many pianists play B9 whenever B7 appears, because the 9th makes the same pull sound richer.
Turn B9 into a reflex
In ChordRunner every correct chord moves your runner forward. Plug in a MIDI keyboard or let the microphone listen to your piano. Dominant 9ths appear in the later boss challenges, next to major and minor 9ths.
Play the demoCommon questions
How do you play B9 on the piano?
Press B, D#, F#, A and C# together. Left hand plays B A (fingers 5 and 1), right hand D# F# C# (1, 2, 4).
What is the difference between B9 and B7?
B7 is B D# F# A. To get B9, add C# above the seventh.
Where is B9 used?
B9 is the V chord of E major: it pulls home to E. Many pianists play B9 whenever B7 appears, because the 9th makes the same pull sound richer.
Can I practise B9 with a MIDI keyboard or a real piano?
Yes. In ChordRunner a USB MIDI keyboard is detected automatically, and an acoustic or digital piano works through the microphone. The game checks that B, D#, F#, A and C# sound together.
Your instrument is the controller.
ChordRunner is a browser game that teaches piano and guitar chords: a chord appears on screen, you play it on a real instrument, and your runner jumps. MIDI keyboard or microphone, both work.
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