The masterful music theory trick that saved The Beatles song ‘Yesterday…
When discussing the enduring appeal of The Beatles’ classic “Yesterday,” it’s impossible not to marvel at the song’s elegant simplicity and emotional depth. Behind its gentle melody and poignant lyrics lies a clever use of music theory—specifically, the unexpected use of a **minor key** and a **chromatic bass movement**—that elevates the song from a straightforward ballad to a masterpiece of harmonic ingenuity.
**The Context: An Acoustic Breakthrough**
Written primarily by Paul McCartney in 1965, “Yesterday” was a departure from The Beatles’ earlier rock-and-roll style, showcasing a more sophisticated, introspective ballad. Recorded solo with an acoustic guitar and a string quartet, the song’s arrangement and harmonic structure play a crucial role in its emotional impact.
**The Key and Its Unexpected Shift**
Most listeners perceive “Yesterday” as a simple, melancholic tune in F major. However, the song’s harmonic foundation actually hinges on a subtle yet powerful music theory trick: the use of **modal interchange** and **borrowed chords** that momentarily suggest a minor key or a different mode, adding depth and poignancy.
The song is primarily in **F major**, but it features a particularly striking harmonic move: the use of a **flat sixth chord**, or **bVI**, borrowed from the parallel minor key—**F minor**. This chord appears as a **bVI (D♭ major)** and is used in the progression in a way that creates a rich chromatic tension.
**The Harmonic Trick: The Use of the bVI Chord**
In the verses, the progression often moves from the tonic **F** to the **bVI (D♭)** chord. This D♭ major chord doesn’t naturally belong to F major; it’s borrowed from the F minor scale. Its inclusion introduces a **modal interchange**—a common technique in music that allows composers to borrow chords from parallel keys or modes to add color.
Here, the D♭ major chord functions as a **pre-dominant** that creates a **surprising chromatic shift**. This shift adds a sense of longing or melancholy, which aligns perfectly with the song’s emotional theme.
**The Effect of the bVI Chord**
This borrowed chord does two things:
1. **Creates a Smooth, Yet Unexpected, Modulation:** The D♭ major chord acts as a pivot, leading smoothly back to F or to other related chords, but its chromatic nature catches the ear and adds emotional weight.
2. **Injects a Sense of Nostalgia and Melancholy:** Borrowed chords from the minor key evoke a more somber or reflective mood, contrasting with the major tonality. This enhances the song’s emotional depth without making it overly complex.
**The Use of the Picardy Third and Other Techniques**
Adding to this harmonic richness, the song also employs a **Picardy third**—ending a phrase with a major chord in a minor context—or similar embellishments to reinforce the emotional tone.
**The Role of the Melody and Arrangement**
While the harmonic structure is crucial, the melody complements it perfectly. McCartney’s vocal line emphasizes the emotional peaks, and the minimalistic arrangement allows each harmonic shift to resonate.
**Why This Trick Is Masterful**
The use of the **bVI borrowed chord** is a subtle but powerful music theory technique. It transforms what could be a straightforward major key ballad into an emotionally complex piece, providing a sense of longing and introspection that resonates deeply with listeners.
This harmonic approach isn’t overly complicated but demonstrates how strategic use of borrowed chords and modal interchange can elevate a song’s emotional impact. It’s a perfect example of how a simple change—adding a borrowed chord—can make a song timeless.
**In Summary**
The “music theory trick” that saved “Yesterday” involves the clever borrowing of a **D♭ major chord** from the F minor key, creating a **chromatic, emotionally charged harmonic shift** within the song’s primarily major key. This nuanced harmonic movement adds depth, longing, and a touch of melancholy, contributing significantly to the song’s enduring appeal. It’s a testament to the power of music theory—how small, thoughtful choices in harmony can profoundly shape a song’s character and emotional resonance.
