Unfigured bass, less commonly known as under-figured bass, is a kind of musical notation where the performer improvises an accompaniment from a given bass line which lacks the guidance of figures (see Wikipedia:figured bass).
From the earliest days of Wikipedia:thoroughbass, Wikipedia:composers and copyists have been chastized for providing bass (WP) parts without any figures to guide performers. Despite perennial complaints, however, unfigured basses persisted right through the Wikipedia:eighteenth century. Though it is speculated that unfigured basses would not have existed if it were not for the suggestion of harmonies in bass lines of the time.
In the early baroque period published parts were as likely to be unfigured as figured, leading to unusual clashes of Wikipedia:harmony on a first reading. In an effort to perform a piece the first time without such harmonic clashes, various methods were devised and used to anticipate the harmonic structure and progression of a piece. Among these are:
- Specific chords might be placed over a given Wikipedia:solmization syllable, or an easily identified note, such as a sharped note.
- Specific chords might be applied to various patterns of bass intervals.
- Model bass lines with chords might be learned by rote to be used whenever applicable.
- Or specific chords might be placed over particular scale degrees.