Deciphering accidentals

I have had a number of questions about last week’s free arrangement of What a Friend We Have in Jesus so today I want to talk more about the harmony.

Let’s start with a definition. Diatonic chords are chords that are naturally derived from the key. In other words, all the notes in the chord are part of the scale of the key. If you are playing in Eb, a diatonic chord will contain some subset of the notes Eb, F, G, Ab, Bb, C, and D.

What that means is this: if you look at a song and you see a chord with no accidentals, it is diatonic. If you see a chord with accidentals, it is not diatonic.

In typical, simple music, the chords are diatonic. Diatonic chords can have dissonance but it is not complex dissonance. In fact, it is very hard to build complex music by today’s standards solely with diatonic chords. It can be done and you will see many piano arrangements that consist either entirely or almost entirely of diatonic chords. The free arrangement I put out two weeks ago (Be Still My Soul) is an example of that. It may be the only 99% diatonic arrangement I have ever published and is a result of me sort of challenging myself to do one like that. If you look at the next to the last measure, you will see that I failed. I just couldn’t stop myself.

In general though, when I look at music, at a quick glance, I can get an idea of the complexity of the harmony by seeing how many accidentals there are. It doesn’t mean it is good harmony, but the presence of accidentals in a song does mean something.

My arrangement of “What a Friend We Have in Jesus” has a high ratio of accidentals. Again, that does not make it good but it does indicate I went off the beaten path a bit more than normal. Every accidental is intentional and I want to talk about where they come from.


Let’s start with bar 4 and specifically the last two beats of the bar. The two chords you see there are Csus7 (formed by the C, F, and Bb) and C7 (formed by the C, E, and Bb). But yes, there are extra notes in the mix too. The Csus7 has a Db and the C7 has a Ab and Eb moving to Db).

The first thing I need to know when using these kinds of notes is what they actually are. In the context of a C chord, Db is the flat 9, Eb is the #9, and Ab is the b13. I can identify notes like that very quickly not because I am overly bright but because I have been doing this a long while. It may seem complex at first but with time, identifying notes within a chord because as simple as reading the newspaper.

The second thing you need to know is when these kinds of notes will work because they for sure don’t always work. For example, they would most definitely not sound good if the chord was Cmin7 instead of Csus7 or C7. If you study this arrangement, you will see that I most often use those kinds of notes on dominant chords because dominant chords like those kinds of sounds.

The third thing to know is how those notes affect the overall style of the piece. The use of these kinds of added notes moves the music toward complexity that is associated with jazz. There is nothing wrong with that of course but I always have to remember that the overall arrangement has to be consistent. Using one #9 in the middle of a mostly diatonic piece of music is going to be a bit strange. It is sort of all or nothing. And on top of that, there is a tension between complexity and accessibility. To me, it is silly to make music complex for the sake of complexity when your complexity is just serving to turn off the average listener. Again, to me, that is common sense, but probably 75% of all jazz pianists seem to fall into that trap and then subsequently wonder why no one likes their music.

Some non-diatonic notes are more on the edge than others. The b9 is fairly common and probably does not rub many people wrong. Nor does the b13. The #9 is another story. I don’t use it that much. The last non-diatonic note is the #11 and I use it very rarely. (An example of a #11 is bar 37 of Fairest Lord Jesus).

When a dominant chord contains both a b13 and either a b9 or #9, it is called altered. The last beat in the example above is called an altered C7. So is this run:



Like most runs, this is not as complicated as it looks. I think of it as a 6-note run consisting of #9, b9, 1, 7, b13, 3. It is quite easy to play if you work out the fingering. The left hand has 1 and 3 of the C7 chord.

This doesn’t explain all the accidentals you see in the arrangement but certainly accounts for a lot of them. For more information, see the original post where I talked about some of the other things going on.