How do you play the C 9(#11)/C# chord?

To play the C 9(#11)/C# chord on piano, play the C 9(#11) chord (C, E, G, A#, D and F#) with C# as the lowest bass note. Place the C# note below the other chord tones. Slash chords specify a particular bass note different from the chord root.

What is a slash chord?

A slash chord (or compound chord) is written as Chord/Bass and specifies both a chord and a bass note. The note to the right of the slash is played as the lowest note. The C 9(#11)/C# chord means a C 9(#11) chord with C# in the bass.

C 9(#11)/C#

Q: What notes are in the C 9(#11)/C# chord?

The C 9(#11)/C# chord uses the 6 notes of the C 9(#11) chord — C (Perfect unison), E (Major third), G (Perfect fifth), A# (Minor seventh), D (Major ninth) and F# (Augmented eleventh) — with C# played as the bass note in the lowest register.

The C 9(#11) chord consists of the C (Perfect unison), E (Major third), G (Perfect fifth), A# (Minor seventh), D (Major ninth) and F# (Augmented eleventh) notes, with C# as the bass note.

Piano keyboard showing the notes for a C 9(#11)/C# chord

How to play the C 9(#11)/C# chord

Play C# as the lowest bass note in the left hand
Find C (Root) on the piano keyboard
Add E (Major third) — 4 semitones above C
Add G (Perfect fifth) — 7 semitones above C
Add A# (Minor seventh) — 10 semitones above C
Add D (Major ninth) — 14 semitones above C
Add F# (Augmented eleventh) — 18 semitones above C
Press all 7 notes simultaneously to sound the C 9(#11)/C# chord