What use is knowing how many sharps or flats a key signature has?

Books and articles I've read on learning key signatures seem to focus on mnemonics that tell you how many sharps or flats the key has, but I don't understand how knowing B Major has 5 sharps helps you to play in B Major - don't you still need to know which sharps?

• Sure you need to know which sharps if you want to play. OTOH, if you just want to know the key quickly by looking at some sheet music, counting is faster and quite sufficient. – leftaroundabout Jun 17 '14 at 23:36
• When you look at a die which has landed 5 up, you don't count the dots. The pattern tells you.It's the same with # or b. Eventually you just know (and which they are). – Tim Jun 18 '14 at 6:25
• "don't you still need to know which sharps?" Yes, but they start at F# and continue though fifths, so it's always F#, C#, G#, D#, A#. So there's a degree of "memorize the result" versus "memorize enough of the process to reconstruct the result". Of course, the keys also progress like that. C (0 sharps), G (1 sharp), D (2 sharps), etc., so you can reconstruct how many sharps B should have as well. Memorization is rarely strictly necessary if you know why something is the way it is. Bob Broadley's answer covers this well. – Joshua Taylor Jun 18 '14 at 13:18
• Doesn't the mnemonic you use TELL you which sharps? You learn 'F C G D A E B.' Not 'G=1, E=3' – Laurence Payne Jan 11 '18 at 19:50

The sharps and flats are always "added" in a particular order. So, if you know how many there should be for a key, you can work out what they are. The mnemonics you refer to can help you to remember the order sharps and flats are added in.

To be honest, though, I tell music pupils of mine, that learning key-signatures by using mnemonics is only partially helpful. Eventually most musicians will just know all of the key-signatures. So, another way to learn them, is in the same way you learn individual facts. You could learn them in the same way you learn, say, the capital cities of countries (the capital of Peru is Lima; the capital of "this" is "that"); no mnemonics are going to help you with that.

So…

• Day 1: learn that C Major has no sharps or flats in the key signature; G Major has an F#; F Major has a Bb.
• Day 2: check what you learnt the day before; learn that D Major has two sharps, F# and C#; learn that Bb Major has two flats, Bb and Eb.

And so on, up to 7 sharps (C# Major) and 7 flats (Cb Major). (Of course, there is no need for these to be learned in a week! I could have said, Week 1: learn… Week 2: learn…)

There are, of course, patterns and rules for the sharps and flats used in different key-signatures, but if you have learnt the key-signatures, you can then look for and understand these patterns and rules.

BTW, I am certainly not advocating learning by rote without understanding. But this approach comes from experience. Often I have tried to explain the cycle of fifths and how you can work out key-signatures, to pupils just starting to learn music theory, and then realised that it is easier for them to learn a few key-signatures first, and then apply the rules later, to help them learn the rest.

Yes, the rules and patterns are important, but eventually a musician needs to know key-signatures without having to recite a mnemonic, so why not learn them this way to start with? Another similar example of learning aspects of music is the mnemonics for learning the notes on the stave (eg. Every Good Boy Deserves Fruit). This might be useful when you are just getting started, but it makes sight-reading very slow!

As a reference, this is the list of major key-signatures:

• C Major (no sharps or flats)

"Sharp" Keys:

• G Major (1 sharp - F#)
• D Major (2 sharps - F#, C#)
• A Major (3 sharps - F#, C#, G#)
• E Major (4 sharps - F#, C#, G#, D#)
• B Major (5 sharps - F#, C#, G#, D#, A#)
• F# Major (6 sharps - F#, C#, G#, D#, A#, E# - enharmonically the same as Gb Major)
• C# Major (7 sharps - F#, C#, G#, D#, A#, E#, B# - enharmonically the same as Db Major)

"Flat" Keys:

• F Major (1 flat - Bb)
• Bb Major (2 flats - Bb, Eb)
• Eb Major (3 flats - Bb, Eb, Ab)
• Ab Major (4 flats - Bb, Eb, Ab, Db)
• Db Major (5 flats - Bb, Eb, Ab, Db, Gb)
• Gb Major (6 flats - Bb, Eb, Ab, Db, Gb, Cb - enharmonically the same as F# Major)
• Cb Major (7 flats - Bb, Eb, Ab, Db, Gb, Cb, Fb - enharmonically the same as B Major)

And, of course, each major key has a relative minor key, which shares its key-signature. You can easily work out the relative minor of any major key; the relative minor is a minor-third (three semitones) lower than its relative major key:

• A Minor is the relative minor of C Major (both have no sharps or flats)
• E Minor is the relative minor of G Major (1 sharp)
• B Minor is the relative minor of D Major (2 sharps)
• F# Minor is the relative minor of A Major (3 sharps)
• C# Minor is the relative minor of E Major (4 sharps)
• G# Minor is the relative minor of B Major (5 sharps)
• D# Minor is the relative minor of F# Major (6 sharps)
• A# Minor is the relative minor of C# Major (7 sharps)
• D Minor is the relative minor of F Major (1 flat)
• G Minor is the relative minor of Bb Major (2 flats)
• C Minor is the relative minor of Eb Major (3 flats)
• F Minor is the relative minor of Ab Major (4 flats)
• Bb Minor is the relative minor of Db Major (5 flats)
• Eb Minor is the relative minor of Gb Major (6 flats)
• Ab Minor is the relative minor of Cb Major (7 flats)

(Again, the same enharmonic relationships exist as for major keys.)

Finally, rather than using mnemonics, you can combine the "factual-learning" and "pattern-learning" approaches:

• as you go up a fifth from C Major, each new key signature adds a sharp, and this sharp is the note a semitone below the new key; eg. G Major adds an F#; D Major adds a C#…
• as you go down a fifth from C Major, each new key-signature adds a flat, and this flat is the note which is the same as the next key down-a-fifth; eg. F Major adds a Bb; Bb Major adds an Eb; Eb Major adds an Ab…

The order for adding sharps is: F# C# G# D# A# E# B#

The order for adding flats is the same reversed: Bb Eb Ab Db Gb Cb Fb

Learn the key-signatures as "facts". Learn patterns within the key-signatures as "facts". Only use the mnemonics (if you really need to) to get you started...

• used to play hand-written big band stuff where the writer would put 2# anywhere, on the stave, for the key sig. It didn't really matter, as one knows that two sharps can only mean Dmaj. (or Bmin.) and the sharps could only be F# and C#. – Tim Jun 18 '14 at 5:20
• Have you, or anyone else, come across the practice of signing key signatures, as in Eb - 3 fingers pointing down, G - 1 pointing up ? Very useful for busking and for deps who have no charts etc. – Tim Jun 18 '14 at 5:25
• You don't even have to memorize the entire order. Just the first two. For sharps, you start with F# and C#. Then go one up sequentially for the following pairs (3rd is one up from F# => G#, 4th is one up from C# => D# etc.). For flats, you start with Bb and Eb, then go one down sequentially for the following pairs. – awe Jun 18 '14 at 7:56
• @Tim, I think my neighbour keeps telling me to play in D Major... – Bob Broadley Jun 18 '14 at 22:52
• C#'s relative minor is actually A# minor. Bb minor is the relative of Db. # and b tend not to get mixed. THAT'S nitpicking !! – Tim Jun 19 '14 at 9:20

For me personally, I play bass guitar. Sight reading with guitar and bass (and other similar stringed instruments) can be really tricky because we have so many places on the instrument to play the same note. Being able to see two flats at the beginning of the piece and quickly say to myself "Ok - key of Bb. Bb and Eb" allows me to find my position and get going without too much thought.

Knowing exactly how many isn't the important part, since the accidentals are always in the same order according to the circle of fifths/fourths. Seeing the consistent marking of two flats, or 4 sharps, and knowing what they represent immediately is what helps quick understanding and successful reading. (Hope that made sense, there).

• On guitar/bass, I never think about any fret/string as being a sharp, flat or natural. Like you probably do, I position my hand, and the appropriate (if I'm lucky!) notes for that scale/mode/arp.are there ready. Whereas on keys, the sharps/flats are the signposts that help me find my way.E.g. D is always between the two black notes. On gtr/bass, there are no such patterns, and indeed the exact same note can be found in many different places.The 2#, 4b etc help in very different ways from keys to gtr/bass.But I will keep practising !! – Tim Jul 7 '14 at 16:19

Because the sharps and flats always come in the same order: F#, C#, G#, D#, A#, E# and B#, in that order. The flats are exactly the opposite: Bb, Eb, Ab, Db, Gb, Cb, Fb. So, if you know there are five sharps, then you also know that those five sharps must be F, C, G, D, and A.

Speaking of mnemonics, the order of sharps and flats can be memorized with the invertible sentence:

Father Charles Goes Down And Ends Battle

for sharps, and:

Battle Ends And Down Goes Charles' Father

for flats.

For some instruments, say chromatic percussion, it is helpful to know if a key has odd or even number of sharps/flats, since it could help with working out the sticking, because, with two hands, if a key has even number of sharps/flats, the cross-sticking (or the lack of) is symmetrical in the lower and upper part of the scale.

"Sharp" Keys:

• G Major (1 sharp - F#)
• D Major (2 sharps - F#, C#)
• A Major (3 sharps - F#, C#, G#)
• E Major (4 sharps - F#, C#, G#, D#)
• B Major (5 sharps - F#, C#, G#, D#, A#)
• F# Major (6 sharps - F#, C#, G#, D#, A#, E# - enharmonically the same as Gb Major)
• C# Major (7 sharps - F#, C#, G#, D#, A#, E#, B# - enharmonically the same as Db Major)

I can see a relationship here. If I saw some sheet music with, say, 3 sharps I could work out that it was A Major. Or if the music 4 sharps I could say it was in E major.

However, for music written with flat keys; if I saw a piece of music written with three flat, example, I couldn't tell you what key it was in.

"Flat" Keys:

• F Major (1 flat - Bb)
• Bb Major (2 flats - Bb, Eb)
• Eb Major (3 flats - Bb, Eb, Ab)
• Ab Major (4 flats - Bb, Eb, Ab, Db)
• Db Major (5 flats - Bb, Eb, Ab, Db, Gb)
• Gb Major (6 flats - Bb, Eb, Ab, Db, Gb, Cb - enharmonically the same as F# Major)
• Cb Major (7 flats - Bb, Eb, Ab, Db, Gb, Cb, Fb - enharmonically the same as B Major)

The requirement to learn this incredibly complicated set of scales only arises because we use a stave that doesn't contain all the notes and we play on a piano that is illogically laid out.

There are 12 notes in an 'octave' not 8.

A major scale plays these eight notes 1/3/5/6/8/10/12/1.

A minor scale plays these eight notes 1/3/4/6/8/9/11/1

If we wrote music with a stave of 12 notes not 8 and played a piano with 6 white keys alternating with 6 black keys, you wouldn't need to know what flats and sharps there were because there wouldn't be any (and playing Rachmaninov's piano concerto would be possible for people with small hands).

Sharps and flats don't really exist: they are just a (bad) way of referring to the 12 notes in the 'octave'. The fact that a note is called eg Bb doesn't mean that somehow you are playing B flat. Nor to the ear does a scale that is full of sharps or flats somehow sound more complicated.

So, first thing, don't worry about sharps and flats. It's not your fault. It is the fault of musical history.

Just remember those gaps above.
A major scale plays notes 1/3/5/6/8/10/12/1.

A minor scale plays notes 1/3/4/6/8/9/11/1

If you feel you must learn the sharps and flats, just write out a 12 by 12 table (excel spreadsheet is best). Label the columns A, A# etc. Colour the columns 2/4/7/9/11 as black notes (OK colour them yellow notes to be able to read them) and fill in the cells on the first row starting with A, then A#, using the numbers/intervals above. Then do the next row (A#) shifting the row of numbers one column to the right of course.

Get that picture in your head, and life becomes much easier, and you start seeing the scales of black and white notes.

If you are playing a scale with an 'ordinary' name (e.g. G), other than F, or a sharp, the black notes are called sharps. If you are playing a 'flat' scale or F then the black notes are called flats.
That's only done because otherwise you end up missing out letters (e.g. D# scale is D#,F,G,G#,A#,C,D,D#; it's easier to talk instead about Eb scale as Eb F G Ab Bb C D Eb). Shows how ridiculous this musical notation is. If we gave the twelve notes separate names (e.g. M,N,O,P,Q,R,S,T,U,V,W,X) the problem wouldn't arise.

One day, maybe, someone will revolutionise musical notation. Probably a robot. It will be like going from thinking the sun goes round the earth to the earth goes round the sun: suddenly you'll make sense of your scales instead of all this nonsense about sharps and flats. The other side of the coin is that everyone would have to relearn sight-reading and piano playing. But not violin playing.

Dunno if that helps. At least it gives you something to argue about with your teacher.

• "If you are playing a 'flat' scale or F#" Do you mean "or F"? I'm also pretty troubled by your claim that "sharps and flats don't really exist"... – Richard Mar 26 '18 at 0:00

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