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B♭ 9♯11

chord·/chords/9-sharp-11/b-flat/

The B♭ 9♯11 chord contains the notes B♭, C, D, E, F, and A♭.

Notes: B♭, C, D, E, F, A♭ · Piano keys: B♭ C D E F A♭

Reviewed for accuracy · Last updated July 2026 · Maintained by Justin Evans

A♯ 9♯11
This is the same chord as A♯ 9♯11 — the same keys on the keyboard, spelled with sharps.
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B♭
B♭ – C – D – E – F – A♭

Practice B♭ 9♯11

Reading about it is one thing. Drilling it is what makes it automatic.

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Introduction

The B♭ 9♯11 chord is a six-note chord made up of B♭, C, D, E, F, and A♭.

Notes

Notes:B♭ – C – D – E – F – A♭

Key Signature

A chord has no key signature of its own, but the B♭ 9♯11 is the tonic (I) chord of Bb Major, whose key signature has 2 flats (B♭, E♭).

B♭E♭

Order of flats

Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.

B♭E♭A♭D♭G♭C♭F♭

Mnemonic: Battle Ends And Down Goes Charles’ Father

Chords in the Key of B♭ Major

These are the triads built on each degree of the B♭ major scale:

C1C2C3C4C5DFC6C7C8A#
I — B♭ Major (major)
DegreeNumeralChordQuality
1IB♭ MajorMajor
2iiC MinorMinor
3iiiD MinorMinor
4IVE♭ MajorMajor
5VF MajorMajor
6viG MinorMinor
7vii°A DiminishedDiminished

B♭ 9♯11 — Frequently Asked Questions

What is the B♭ 9♯11 chord on piano?
The B♭ 9♯11 chord contains the notes B♭ – C – D – E – F – A♭. On piano, play these notes together to sound the chord.

Related Tools

Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.

References & Further Reading

The note names, intervals, fingering, and harmony on this chord page are grounded in the following sources. Public domain treatises and scores are linked to their full text; primary data reflects piano.org's own interval-derived dataset.

  1. 1

    George Grove (ed.)(1900)

    A Dictionary of Music and Musicians

    Public domain treatise
  2. 2

    Jadassohn, Salomon(1883)

    A Manual of Harmony

    Public domain treatise
  3. 3

    Prout, Ebenezer(1889)

    Harmony: Its Theory and Practice

    Public domain treatise
  4. 4

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