Rousseau wanted to simplify music notation, believing that the traditional system was too complex. He was only interested in the method of writing down, transmitting and preserving music. Rousseau focused on on the expression of all possible sounds and all different durations, both sounds and their relative silences. He started from a fundamental sound, C (in other words Do), expressed by the number 1; then the seven natural sounds of the tempered keyboard (ut, re, mi, fa, sol, la, si) by the seven digits 1, 2, 3, 4, 5, 6, 7.
To express a change of octave, he used a point above the note to signify the octave immediately above. The placement of this point also indicates that the following notes belong to this octave until the next sign. For the octave immediately below the note considered, the point is placed below. The number of points designates the number of octaves raised or lowered.
The system has been mostly forgotten in the west, but remains widely used in China under the name Jianpu .