• A Study On The Major Key

    in Chords & Progressions,Piano,Theory

    In this lesson, we’ll be doing a study on the major key.

    Most times within the company of musicians, it’s common to hear phrases like “The Key of C major,” “A Major” etc. If you’re not really into music per se, you can literally think it’s a game of alphabets, like saying, “Key M major” or “Key P major.” :)

    We’ll be learning what’s behind the term major key, but before we do, let’s define key.

    Before The Concept Of Key

    Several centuries ago, what we know today as key, was not in use. Musicians who lived between AD 400 and 1400 (aka – “medieval ages”) made extensive use of modes.

    A mode [that is not transposed] consists of a collection of white notes (aka – “naturals”) from a given white note to its octave. There are seven natural notes on the piano – A to G:

    …and each natural note can form a mode. Check out the modes…


    From C to C:

    …the ionian mode.

    From D to D:

    …the dorian mode.

    From E to E:

    …the phrygian mode.

    From F to F:

    …the lydian mode.

    From G to G:

    …the mixolydian mode.

    From A to A:

    …the aeolian mode.

    From B to B:

    …the locrian mode.

    These modes in their days, occupied the place of what we now call the tonality, key center, or key. Instead of having music written in a variety of keys – A major, Eb major, etc., music composition was done using modes in the medieval ages.

    Read more on the classification of modes into major and minor modes, in this post.

    Evolution Of The Key Centers

    The 17th century was the age of reformation. There were remarkable changes that took place in the arts and specifically in music. Tonality was introduced and it replaced the medieval modes we just covered.

    The use of tonality is the establishment of a given note on the keyboard as a central tone or tonic. In this tonal environment, an attraction is created towards a particular note, known as the key center, tonal center or key.

    There are two dynamic tonalities that can be formed when a note is established as a key center and they are called the major and minor keys.

    The major tonality captures emotional feelings like brightness, happiness, etc., while the minor tonality can be used to depict darkness, sadness, etc. The use of the major and minor keys replaced the modes that were used earlier.

    The major key is related to the ionian mode while the minor key is related to the aeolian mode.

    Transposing the ionian mode to every other key producers the major scale in those keys. Alternative, the transposition of the aeolian mode to other keys produces the minor scale.

    The Major Key

    The major key is the key center made up of a step-wise arrangement of notes in whole steps with half step between the 3rd & 4th degrees and 7th & 8th degrees.

    Often times, piano instructors introduce the major key to students using the key of C major, which consists of these notes:

    …arranged in whole steps [and half steps.]

    The third and fourth degrees :

    …of this major key has half steps in between, and so does the seventh and eighth degrees:

    Let’s round up today’s study by looking at some important components of the major key

    Avoid Note

    The fourth tone in the major key is considered as an avoid note [for a variety of reasons.] One of them is that the fourth tone has the least level of consonance with the tonic chord.

    In the key of C:

    …playing the fourth tone (F):

    …over the tonic chord (C major triad):

    …produces an unpleasant harmony.

    Further reading: Avoiding the avoid note.

    The Major Scale

    The notes of the major key if played in a succession in ascending and descending order would produce the natural major scale. If the notes in the key of C major:

    …are played from C:

    …to C:

    …in a melodic manner, the outcome would be the C major scale, which is the traditional scale of the major key.

    Suggested reading: The Natural Major Scale.

    Simple Intervals

    An interval is the relationship between two notes [in terms of the distance between them].

    Intervals can be formed between any two notes of the natural scale. However, in this segment, we are concerned with intervals that are formed between the first note of the major scale [aka – “tonic”.]

    In the C major scale:

    …the tonic is C:

    Therefore, we can form the following simple intervals between the tonic and other tones in the key. Check them out…

    C and C:

    …a perfect unison, formed between the tonic and the first tone of the scale.

    C and D:

    …a major second, formed between the tonic and the second tone of the scale.

    C and E:

    …a major third, formed between the tonic and the third tone of the scale.

    C and F:

    …a perfect fourth, formed between the tonic and the fourth tone of the scale.

    C and G:

    …a perfect fifth, formed between the tonic and the fifth tone of the scale.

    C and A:

    …a major sixth, formed between the tonic and the sixth tone of the scale.

    C and B:

    …a major seventh, formed between the tonic and the seventh tone of the scale.

    C and C:

    …a perfect octave, formed between the tonic and the eighth tone of the scale.

    Apart from the perfect intervals formed between the tonic and the first, fourth, fifth, and eighth degrees of the major scale respectively, the rest are major intervals. If you do the math, four out of eight (50%) simple intervals formed in a major key are major intervals.

    It is the quality of these intervals formed in relationship with the tonic that gives the major key its major quality.

    The Tonic Chord

    According to Jermaine Griggs, “A chord is a collection of three or more related notes.”

    If a chord is formed on the first tone of the key, a chord is called the tonic chord. In the key of C major, we can play this collection of notes:

    …that are related in thirds (aka – “tertian harmony“) as the tonic chord because the root of the chord is C:

    …which for all intents and purposes is the tonic of the C major scale.

    Further reading: The Tonic Chord.

    Primary Chords

    There are four common triad qualities – the major, minor, diminished, and augmented triads, known to HearandPlay students [like me] as the fantastic four.

    Although the major key has 75% of these common triad qualities – the major, minor, and diminished triads, the triads that have the same quality with the key are called the primary chords, the rest are known as secondary triads.

    If you evaluate the quality of all the scale degree triads in any given major key, you’ll discover that only triads of the first, fourth, fifth degrees have the major quality. Therefore, triads of the first, fourth, and fifth degrees of the major key are primary chords in the key.

    In the key of C major:

    …the primary triads are the C major triad:

    …of the first degree, the F major triad:

    …of the fourth degree, and the G major triad:

    …of the fifth degree.

    Attention: Primary chords are used in elementary keyboard harmony, a subject we’re delving into in subsequent posts.

    Final Words

    For beginners, I highly recommend you practice the major scale, simple intervals, tonic chords, and primary chords, in all the twelve keys of the piano.


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    Onyemachi "Onye" Chuku is a Nigerian musicologist, pianist, and author. Inspired by his role model (Jermaine Griggs) who has become his mentor, what he started off as teaching musicians in his Aba-Nigeria neighborhood in April 2005 eventually morphed into an international career that has helped hundreds of thousands of musicians all around the world. Onye lives in Dubai and is currently the Head of Education at HearandPlay Music Group and the music consultant of the Gospel Music Training Center, all in California, USA.

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