Button chart

B/C button accordion

The B/C box is the button accordion of Irish music. Its two rows are a semitone apart, B outside with eleven buttons and C inside with ten, and between them they give you almost every note across three octaves. There are no accidental buttons because none are needed.

Like a melodeon, each button gives one note on the push and another on the pull, and the home notes are on button 3 from the chin end.

Each button shows its push note on the left and its pull note on the right, with the octave (middle C is C4). Buttons are numbered from the chin end; a ′ marks the inside row, as in English tab.

Every button

B row, the outside row
Button	Push	Pull
1	D♯₃	G♯₃
2	F♯₃	A♯₃
3	B₃	C♯₄	home note
4	D♯₄	E₄
5	F♯₄	G♯₄
6	B₄	A♯₄
7	D♯₅	C♯₅
8	F♯₅	E₅
9	B₅	G♯₅
10	D♯₆	A♯₅
11	F♯₆	C♯₆

C row, the inside row, written with a ′ in tab
Button	Push	Pull
1′	E₃	A₃
2′	G₃	B₃
3′	C₄	D₄	home note
4′	E₄	F₄
5′	G₄	A₄
6′	C₅	B₄
7′	E₅	D₅
8′	G₅	F₅
9′	C₆	A₅
10′	E₆	B₅

Range

The treble side runs from D♯₃ to F♯₆, a little over three octaves. Inside that range only three notes are missing: F₃, D₆, F₆.

Notes you can play two ways

These notes are on more than one button, often one on the push and one on the pull. That choice is what lets you avoid a change of bellows in the middle of a run, and it's where different fingerings come from.

Note	Where to find it
B₃	3 push, 2' pull
E₄	4 pull, 4' push
B₄	6 push, 6' pull
E₅	8 pull, 7' push
B₅	9 push, 10' pull

The bass side

Eight basses in chord and bass pairs. On the push the outer row gives G and C, and the pull gives D and G. The inner row has E on the push with A on the pull, and C on the push with F on the pull.

Row	Button	Push	Pull
Outer	Chord	G	D
	Bass	G	D
	Chord	C	G
	Bass	C	G
Inner	Chord	E	A
	Bass	E	A
	Chord	C	F
	Bass	C	F

Other versions of this layout

Bass layouts vary more than the treble. This chart shows the traditional one. Some makers put D and F where this has C and F on the inner row.

Boxes with 23 buttons add one at the chin end of each row, which moves the home notes to button 4.

A C♯/D box is the same layout a whole tone higher, with the C♯ row outside and the D row inside.

Scales on this box

Each of these has its own page, with the buttons for every note and a way through the octave. Which keys suit a B/C compares all of them.

Where this chart comes from

This is the B/C layout built into Squeezebox Studio. Before it went into the app it was checked note for note, octaves included, against these independent charts:

Other charts: D/G melodeon, G/C melodeon, D/G melodeon, Anahata layout.