Music Theory: Identifying the key of a piece
- Anne Lam Music
- Mar 31
- 4 min read
Hello everyone, welcome back to another music theory lesson! Today we're going to be talking about how to figure out the key of a piece. More specifically, when we see the key signature, how do we know that it's actually in the corresponding major key, or if it's actually in its relative
minor? We're going to go through a few examples together to learn about this topic.
Now, obviously, if you're someone who has either perfect pitch or really, really strong relative pitch, when you look at a score of music, you can already kind of hear what it sounds like in your head. Just based on that alone, you can hear whether a piece is major or minor, without actually playing it. However, what we're going to focus on today is actually learning how to determine whether a piece is in its major or relative minor key by looking at the elements within the score.
Example 1:
The first example we're going to look at is Serenade by Schubert.
As you can see, there is a B flat in the key signature. This key signature corresponds to F major. However, we can't ignore the fact that relative minors exist as well. (If you need a refresher on what relative minors are and how to determine them, you can check out my lesson on that topic first, and then come back to this one.) The relative minor of F major is D minor. Now, we have to determine: is this piece in F major or in its relative minor, D minor? How can we tell?
If you look at the very first measure, for example, you will see that the notes form the D minor chord, which is the tonic triad of D minor. Now, this is not to say that all you have to do to figure out the key of a piece is look at the first chord, but it's usually a pretty good indicator. Other things to look for are accidentals within the piece itself. For example, there is a C# in m4. And if we think about D minor, you should know that for each minor key there are three different types of scales. (Again, if you need a refresher on the different types of minor scales, you can check out my lesson on that before coming back to this one.) They are: D minor natural, D minor melodic, and D minor harmonic. If you go through the scales, you will come to realize that the D minor harmonic scale has a C sharp, because that's the raised seventh of that scale. So the C# in m4 corresponds to that D minor harmonic scale. This is yet another indicator that this piece is in D minor, the relative minor of F major.
Still looking at m4, you can see that the notes of this bar form the A major triad. What is the relationship of A major to D minor? It is the major dominant. So, as you can see from just this one line of music, we already have the very first bar indicating the tonic minor chord for us. Then, in the fourth bar, we have the use of the raised seventh in the harmonic minor scale. We also have this dominant major chord of the minor key.
Example 2:
The next example we're going to look at is a very famous piece. This is the Turkish March by Mozart. I'm sure a lot of you have already heard this piece before, and just based on the sound, we can already tell that it's minor. Having said that though, let's analyze it anyway.
There is nothing in the key signature, which corresponds to C major, since the scale has no flats and no sharps. The relative minor of C major is A minor. Putting the sound of the tune aside, how can we tell just based on looking at the score that it's an A minor and not C major? If you look at the first full bar, ignoring the pickup, the notes in that bar form the A minor triad, which is the tonic triad of A minor. Also, if you look at some of the accidentals here, we see F#s and G#s. Are there any A minor scales that have these accidentals? Yes. The A minor melodic scale has F# and G# in its ascending half. Once again, the accidentals correspond to one of the relative minor scales, just like in the previous example.
Example 3:
The last example we're going to go through is the Hungarian Dance by Brahms, which is another very well-known piece. Again, if you've heard the tune before, then you already know it is minor.
Looking at the key signature, we can see three sharps, which corresponds to A major. So, can we tell that this piece is actually in F# minor? If you look at the first two bars, the notes spell out the F# minor chord, which is the tonic triad of F# minor. In m3, we can also see that there is an E#, and in the F sharp harmonic minor scale, the raised 7th is an E# as well. So once again, the accidental is corresponding to one of the minor scales.
Hopefully, you're starting to get the idea. As mentioned earlier, you cannot always rely on that very first chord. That's why it's important to look at the accidentals to see if they indicate that the piece might be in the relative minor instead. If you want more information and more exercises on identifying the key of a piece, you can definitely check out the RCM level 7 theory book. Aside from the concept discussed in today's lesson, there are also many other areas that this book covers, such as rhythm, intervals, transposition, chords and harmony, melody writing, music history, and even form and analysis.
Thank you so much for reading until the end! If you guys have any questions at all, feel free to drop them down in the comments section below. If you feel like you need more personalized help, please contact me to inquire about one-on-one lessons.
Comments