Learn › Amaj9 Chord on Piano (A Major 9th)
New Released in April 2026
Amaj9 Chord on Piano (A Major 9th)
To play the Amaj9 chord on the piano, press A, C#, E, G# and B. It is the major seventh Amaj7 plus the 9th, B. Its sound: soft, dreamy and very open.
No account, no download. The demo has limited content. Advanced features are in ChordRunner Premium.
- MIDI keyboard
- Digital or acoustic piano
- Guitar
- Computer, phone or tablet
Where your hand goes for Amaj9
Each picture is still Amaj9. Move only the notes that must move.
Both hands: A G# C# E B
Rootless, 3rd on the bottom: C# E G# B
Rootless, 7th on the bottom: G# B C# E
Left hand alone: A G#
Hands and fingers
| Left hand | A G# | 5 1 |
|---|---|---|
| Right hand | C# E B | 1 2 4 |
The chord hiding inside Amaj9
Look at the four top notes of Amaj9: C# E G# B. They form C#m7. So Amaj9 is A in the bass with C#m7 on top, an easy way to find it fast.
How Amaj9 is built
Formula 1 3 5 7 9. Count from A and every number is a step of the A major scale, and a b lowers it by one key.
Start chord: Amaj7
| Note | Step | Interval | Keys from A |
|---|---|---|---|
| A | 1 | root | 0 |
| C# | 3 | major 3rd | 4 |
| E | 5 | perfect 5th | 7 |
| G# | 7 | major 7th | 11 |
| B | 9 | major 9th | 14 |
Practise Amaj9 in four steps
- Find A, then add the other notes one at a time: A, C#, E, G# and B.
- Play Amaj7, then Amaj9, then Amaj7 again, and hear what the 9th adds to the major seventh.
- Try Amaj9 in a rootless shape with the 3rd on the bottom, the position that sits closest to your last chord.
- Last, meet Amaj9 mixed with chords you already know, in an order you did not plan.
Five minutes a day is enough to make Amaj9 feel easy.
Where Amaj9 is used
- Amaj9 is the I chord of A major and the IV chord of E major.
- It replaces Amaj7 when a song wants a softer, wider sound.
Play Amaj9 in a game
Chord symbols arrive one after another and the game checks every note you play, with MIDI or the microphone. Major and minor 9ths have their own level, "Ninth Chords".
Play the demoCommon questions
What notes are in the Amaj9 chord?
Amaj9 has 5 notes: A, C#, E, G# and B. Formula 1 3 5 7 9.
What is the difference between Amaj9 and Amaj7?
Amaj7 is A C# E G#. To get Amaj9, add B above the major seventh.
Where is Amaj9 used?
Amaj9 is the I chord of A major and the IV chord of E major. It replaces Amaj7 when a song wants a softer, wider sound.
Can I practise Amaj9 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 A, C#, E, G# and B 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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