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I was practicing my scales on the piano and I started to wonder why the F major scale is written with a Bflat rather then an A#?

marked as duplicate by Dom May 1 '18 at 17:28

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    the convention is to use different note names for each scale degree so f,g,a,bflat,c,d,e.. if you would've used a# it would look like f,g,a,a#,c,d,e ... but now you have two a's. and that's not cool with the convention. – foreyez May 1 '18 at 17:57
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    @foreyez -- quite true; also, with A♯ there would be an augmented unison between the 3rd and 4th degrees of the F major scale, which isn't at all how we think of major scales. With B♭ instead there is instead a minor second between the 3rd and 4th degrees, and we can all breathe a little easier.... ;) – David Bowling May 1 '18 at 20:19

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