Just begining to learn to read musical scores. I don't understand why there is a natural on the second note of the 9th measure, since there is no previous sharp or flat?

I assume the natural in the 7th measure cancel the flat of the previous measure even though they are cancelled by being in a different measure etc.

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2 Answers 2


It is a courtesy accidental. This is an extra, unneeded accidental that the composer or publisher has added because they think that a mistake is likely. Here, with many of the Es flattened, including in the immediately preceding measure, the E natural may be a surprise. Many of the Bs are also flattened so the player might be tempted to switch into a B flat gear.

As you say, it is not needed but it is not forbidden either and it may help. Somewhat like adding (sic) in a document where you think that the reader may otherwise assume that you have made a mistake.


I read your question a little too quickly and concentrated on the natural in the 7th measure. As guidot says, the one the in 9th measure is a little unusual. Accidentals (unlike key signatures) apply only to the octave in which they are used. This particular B has not been flattened so it is in even less in need of a courtesy natural. I am not quite sure but I think that I have seen the occasional courtesy accidental in another octave. If B is frequently flattened (as here), the performer might be tempted to think that the key has changed and all Bs will be flattened. They might, like Tim, recognize the blues style but, if they don't then they may suspect that the piece has modulated to B flat.


  • While I agree with the explanation, the courtesy accidental is strange here, since on-the-fly accidentals are octave-dependent and the whole excerpt has no b on this position.
    – guidot
    May 27, 2019 at 13:09
  • 1
    @guidot A good point. I was actually looking at the wrong measure and I commented on one of the earlier Es. I'll amend my answer. I still guess that since there are some many B and E flats, there was a fear that the player may think that the piece has modulated to B flat.
    – badjohn
    May 27, 2019 at 13:20
  • Yes, it could be mistaken for being in Bb. However, thankfully, a lot of musos use their ears well, so it would only be a mistake first time round. Although, playing it on bass, a pattern should emerge - it's the same for each bar, just starting on a different note - C, F or G! And, that natural in bar 9 is so unnecessary!
    – Tim
    May 27, 2019 at 16:51
  • As I commented to your answer, I failed to mentally (or really) play it. If I had then I would have recognized it. I very much doubt that I would have needed that courtesy natural but maybe someone living in a cave has not heard it before.
    – badjohn
    May 27, 2019 at 17:29

One of the most used bass lines in a 12 bar blues! Since it's written in C, but uses the notes from C blues, with the b7th on all the riffs, on the C bars, it's B♭, on the F bars it's E♭, neither in the key sig. Thus accidentals needed. However, there's always a possibility that a reader will forget which notes have been changed, or when they change back (as if!!) so the publisher has printed natural signs which courteously remind that reader that the written notes are naturals, not like the changed notes in the previous bar, which actually get cancelled by the following bar line anyway. It is better to print them thus: (♮), as a way of saying 'you probably know anyway, but here's a reminder!'.

  • I concentrated on the question without (mentally) playing it. I am not much of a bass guitarist but even I have played that. I don't think that I have ever played it in the key of C and I don't think that I have seen it written down.
    – badjohn
    May 27, 2019 at 9:51

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