In notating a key change that applies to a repeating section, does the key signature go before or after the bar line? For example, I have a piece that starts out in C major, then switches to F major. The software I'm using (EasyABC) seems to be able to write it out both ways:



I need to fudge my ABC source to make it use one or the other, but I'm not sure which notation is correct.

  • Also be aware that a cancellation of the last key sig. is usual, at the end of that section, before the new one. It's a number of natural signs corresponding to the # or b in the old key sig. Difficult when the old key is C...
    – Tim
    Commented Nov 6, 2016 at 7:40
  • For questions of this ilk, it's well worth looking at a random sample of 10 or 50 pieces at IMSLP . (imslp.org) Commented Nov 7, 2016 at 12:43

3 Answers 3


The key signature will go after the barline, whether it's a single, repeated, double barline, etc.; thus your second example is the correct one.


As Richard said, the key signature goes after the barline, but strictly speaking the "start repeat" mark is not a barline! For example, start and end repeat marks often occur in the middle of a bar, without interrupting the rhythm of the music.

At the start of a system, there is no barline between the key signature and the first note or rest, but there may be a "start repeat" mark in that position.

You will never see the key signature after the start repeat at the start of a system. Usually, there will be a "cautionary" key signature after the last barline in the previous system - i.e. right at the end of the previous system.

In the middle of a system, the correct notation is this: enter image description here

However there are published scores which (incorrectly, by the modern "rules") omit the "double bar" at the key change, and put the key signature after the "start repeat" sign.

If the music before the key change is also repeated, the key signature goes between the "end repeat" and "start repeat" lines:

enter image description here


Not after a repeat barline. And we generally dispense with "cancellation" accidentals these days, except when moving into C major.

Back-to-back repeated sections with a key change can be inelegant. Part of the copyist's skill lies in trying to avoid such problems mid-line.

The "classical" rules aren't always appropriate for songs with complex repeats, DC al coda etc. structures. Just try to be clear. If you want a laugh, find an orchestral part from one of the multi-section Strauss waltzes. I defy anyone to navigate them at a sight-read, let alone quibbling over key-signature placement!

  • Heh. I've played a couple Strauss pieces. Then there's the mad juggling of keys in Peter and The Wolf, too. Commented Nov 7, 2016 at 12:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.