The Functional Just System (FJS) is a logical notation system for the entirety of just intonation (JI) which claims to be both more coherent and more succinct than both Helmholtz-Ellis notation and Ben Johnston's notation.
The Functional Just System can be seen as an extension of the Pythagorean system: the base name of a note (G, D, Ab, etc.) or interval (P5, M2, m6) is calculated by a fifth distance superscript or subscript numbers are added to mark the deviation from the pythagorean base. The chain of fifths used is controlled by a threshold value (or "radius of tolerance") that is λ=65/63 by default (in “The radius of tolerance is a constant, by definition equal to 65/63.”[1])
Weblinks
Quick reference
Formal commas
Harmonic series
Overtones 1–32 with root C
| 1–8
|
C
|
C
|
G
|
C
|
E5
|
G
|
Bb7
|
C
|
| 9–16
|
D
|
E5
|
F11
|
G
|
Ab13
|
Bb7
|
B5
|
C
|
| 17–24
|
Db17
|
D
|
Eb19
|
E5
|
F7
|
F11
|
F#23
|
G
|
| 25–32
|
G#25
|
Ab13
|
A
|
Bb7
|
Bb29
|
B5
|
B31
|
C
|