Improvisation generally consists in creating a Melody suitable for a given Chord Progression. This means that a score containing only chords is given, and a melody must be composed in such a way that it fits or sounds well with those chords.

That part of the melody corresponding to each chord is composed, in most cases, by notes belonging to a certain Scale related to the chord. According to the CHORD SCALE THEORY, the scales related to a given chord are those containing the notes of the chord.

IMPROCHART is an Improvisation Chart based on the CHORD SCALE THEORY, which automatically gives us all the Scales related to a given Chord. It consists of two rotating discs, one being card and the other plastic. It comes with instructions, scale tables and a practical protective case.

10 basic chord types are considered, plus their possible tensions, as well as 10 scale types. An equivalence table for other types of chords is also included. The scales have been classified into Basic (major, melodic minor and harmonic minor), Symmetric (diminished and whole tone) and Special (several Bebop scales, Pentatonic and Blues). Thus, a complete set of scales is available for improvising on a given chord.

Moreover, with the aim of making the initiation to the improvisation easier and friendlier, a set of practical tables containing all these 10 scale types in every key is included. Finally, this instrument together with the scale tables, are designed in such a way that users need not know how to read music.