Understanding “Thirds” – how standard chords are built!

Hi folks!

In order to understand tutorials on piano playing, it is essential that you know some basic terminology from the world of music theory.  So here’s an important video on “major and minor thirds.”

If you aren’t clear about major and minor thirds, you might want to watch this.  Afterward, you can read the rest of this article, using your newfound vocabulary!

Stacked Thirds

Chords are often understood and learned as a series of “stacked thirds.”  For example, a major seventh chord can be seen as the following stack:

Major third, Minor third, Major third.

Let’s look at the CMaj7 (C Major Seventh) chord as an example of stacking thirds to build a major seventh chord from any root.  The notes of the CM7 chord are C, E, G, and B.  Starting from the root C, we can stack thirds to create the chord.  First we pile on the E, which is a major third above C.  Then we put a G on top of the E.  The musical distance (interval) from E to G is a minor third.  Finally, we top off the stack with a B, which is a major third above the G.  We now have a really tasty sandwich!

OK so here’s the vid with some tips on finding major and minor thirds on your keyboard, starting from any piano key.

Questions, comments? Please jump in. Let’s make this a community!

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