Figured bass (thoroughbass, basso continuo) is a defining feature of Baroque music. The composer wrote out only the bass line and placed numbers below or above it, indicating the required intervals and chords. A performer on the harpsichord or organ “decoded” these numbers and improvised a full chordal accompaniment.
This system, similar to modern jazz chord symbols, prevailed from about 1600 to 1750 and accompanied almost all the music of its time — from opera to the sonata. Figured bass demanded of the performer a perfect knowledge of harmony and taste, making them a co-author of the work. With the decline of the Baroque the system fell out of use, but it remained a cornerstone in the teaching of harmony, and its spirit was reborn in the chord “grids” of jazz and pop music.
