Introduction

The concept of using chords from a relative major key in a minor key, particularly in the context of quasi-half cadences, can be a complex and nuanced topic in music theory. This article delves into the specifics of this phenomenon, explaining how and why a cadence on a relative major can be considered a quasi-half cadence, and the implications of using a major third in a tonic chord in a minor key.

Understanding Quasi-Half Cadences and Cadences in Minor Keys

Firstly, let's clarify some terminology. A cadence is a sequence of chords or harmonies that ends a musical phrase or section. A half cadence typically ends on V (the dominant chord), which leaves the listener feeling that more music is needed. In contrast, a cadence on the relative major involves resolving to a chord that belongs to the relative major key but does not inherently create a resolution to the tonic.

The quasi-half cadence is a theoretical term that refers to a cadence that feels unresolved, but not as strongly as a true half cadence. It is often used to create a sense of anticipation or unease, or to transition to another section. In the case of a minor key, using a chord from the relative major can create this quasi-resolution.

The Picardy Third and Its Role in Minor Keys

A Picardy third is a technique where a major third is used in the tonic chord of a minor key. It is often used to create a brief moment of resolution or a sense of finality, but typically it only occurs at the end of a composition and usually after a temporary or passing modulation. It can function as a half cadence in carefully prepared situations, but it does not usually function as a strong resolution within the key.

Examples and Analysis

Consider the minor key of A minor and the relative major of C major. In a composition in A minor, a chord borrowed from C major might be used to create a sense of quasi-resolution. For instance, a progression might go from A minor (Am7), to F major (F7), to C major (Cmaj7). This creates a sense of transition and unresolved tension, characteristic of a quasi-half cadence.

Theoretical Perspectives

Theorists often explore the boundaries of traditional musical theory to better understand the ways in which musicians can use and interpret music. The use of a relative major chord in a minor key to create a quasi-half cadence is a prime example of this exploration. While some might argue that certain cadences are only valid within their own key, others would argue that the flexibility of music theory allows for a wide range of creative possibilities.

Conclusion

In conclusion, a cadence on the relative major in a minor key can indeed be considered a quasi-half cadence. This concept expands our understanding of how chords and progressions can function within and outside of their primary key. The use of a major third in the tonic chord of a minor key, known as the Picardy third, further adds to the nuances of this technique. Musicians and composers can use these techniques to create a wide range of emotional and thematic effects, contributing to the rich tapestry of musical expression.