As we look back on the life and music of Chick Corea, we want to take this opportunity not just to pay tribute to one of his most famous compositions but to discuss how it utilizes a deceptively simple concept called “modal interchange.”
Modal interchange involves borrowing harmonies from the parallel major or minor of the primary key (or mode.) For example, if the main key of the composition is G major, a songwriter or composer can employ modal interchange by using chords from G minor. This can add additional color while maintaining the continuity of the tonality. George Harrison used modal interchange in “While My Guitar Gently Weeps”: the verses are in A minor while the bridges are in A major. Understanding modal interchange and recognizing examples of it can help an improviser analyze a chord progression and spot the relationships between keys, while for composers and songwriters, it can be a gateway to exploring new harmonic territory.
Outside Pedestrian 