Figured Bass

Figured bass (or thoroughbass) is a shorthand notation system from the Baroque era in which a bass line is written out and numbers (figures) above or below each bass note indicate the intervals to be played above it. A keyboard player reads the bass line and the figures, then realizes the harmony by filling in the appropriate notes. This practice trained musicians to hear and construct harmony rapidly from minimal notation.

The figures specify intervals above the bass, not above the root. Root position triads are unmarked or labeled 5/3 (often abbreviated or omitted). First inversion is 6 (meaning a sixth and a third above the bass). Second inversion is 6/4. For seventh chords in root position the figure is 7; first inversion 6/5; second inversion 4/3; third inversion 4/2 (or 2 alone). Accidentals next to figures apply to the corresponding interval: a sharp raises, a flat lowers, a natural cancels.

Though figured bass is no longer a common performance practice, it remains central to music theory pedagogy. Reading figures sharpens understanding of voice leading and chord construction, since the system forces the analyst to think from the bass upward rather than from an abstract chord label downward. Figured bass symbols survive today embedded in Roman numeral analysis (as inversion indicators) and in continuo parts in Baroque performance editions.