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
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C
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C
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G
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C
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E5
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G
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Bb7
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C
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9–16
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D
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E5
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F11
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G
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Ab13
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Bb7
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B5
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C
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17–24
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Db17
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D
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Eb19
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E5
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F7
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F11
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F#23
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G
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25–32
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G#25
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Ab13
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A
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Bb7
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Bb29
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B5
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B31
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C
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