Mozart's sonata K545, Bar 36, bass clef, the urtext edition from sheetmusic2print shows a natural sign ♮ in front of the F rather than its preceding G (see picture, in red circle), why would the F need the natural sign? On the other hand, the edition I got from free-scores has the natural sign ♮ in front of the G that precedes the F (see arrows in the red circle), which would make sense since the previous two G's have #. HOWEVER, in all the videos I've seen on youtube, the performers played that as G#.

So, if the urtext from sheetmusic2print is correct, why the need for natural sign ♮ for the F? Or could it be a printing error and should belong to the preceding G? Anyone has a trusted urtext edition not from sheetmusic2print to verify? Thanks.

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1 Answer 1


The natural sign before the F is a "courtesy accidental". Because of the F# in the right hand's ascending scale on beats 1 and 2, the natural sign in question is included to avoid ambiguity.

  • Thanks, didn't know the right hand is a concern... So my free-scores edition has yet another mistake! Glad I have asked, or I'd have continued playing the wrong note. Dec 30, 2020 at 0:16
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    Strictly speaking, the right-hand is not a concern. Accidentals only apply to the specific staff line/space they appear on. However, to be on the safe side, many editions will include the courtesy accidental. BTW, sites like free-scores are notoriously unreliable. For things like Mozart, you're generally much better off with a site like IMSLP, where you can also download for free.
    – Aaron
    Dec 30, 2020 at 0:20
  • Thanks. I chose the free-scores because it has fingering and also more readable print (many on IMSLP are scanned copies, not very readable). I think after getting familiar with the fingering I'll use a reliable edition. P.S. in my free-score edition, some parts have an octave higher than it should be, some have an octave lower! Dec 30, 2020 at 0:27
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    It's very unusual to see courtesy accidentals that 'correct' changed notes from other octaves - and other staves. Players at that level shouldn't need them anyway. Instead of helping, it's confused at least one - the OP!
    – Tim
    Dec 30, 2020 at 11:09
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    Just checked Henle Urtext. The "courtesy accidental" is there, so presumably Mozart's notation. Speculation: the rule wasn't codified at that point in time.
    – Aaron
    Dec 31, 2020 at 1:49

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