The Tongan notation was introduced by James Egan Moulton, one of the Methodist missionaries came to Tonga in the 19th century. It is based on “tonic sol-fa” system in which syllables (do, re, mi …) are assigned to the notes. The Tongan notation followed the “movable-do” system in which the “do” moves according to the key. As a result, the interval between the notes (e.g. do-mi) remains the same regardless of the key. For instance, in key C, “do” is C and in key D, “do” is the D.
The Tongan notation’s names were derived from the Tongan numbers’ names. For instance, the number 3 is “tolu”. Therefore the tonic for any key is number 3 and it called “to”, the first syllable of the number 3 “tolu”. One of the advantages for using the numbers is; the number’s value showed the bitch of each note in relation to each other. For instance, the number 5 is bigger than 4 therefore in a same octave the note “ni” (5) is higher than “fa” (4) and the “to” (3) is lower than “fa” (4).
There are seven note number names in Tongan notations, 3 (to), 4 (fa), 5 (ni), 6 (‘o), 7 (tu), 8 (va), and 9 (hi). In the key C major, the 3 (to) is the C note. The 4 (fa) is the D note and so forth. The upper C is a 3 (to) with a dot on top to indicate it is the upper octave. Likewise, the lower octave notes are marked with a dot or hook under the numbers.
The Tongan notations names in C major
| Key C | C | D | E | F | G | A | B | C |
| Solfege | do | re | mi | fa | sol | la | ti | do’ |
| Tongan numbers | 3
tolu |
4
fa |
5
nima |
6
ono |
7
fitu |
8
valu |
9
hiva |
3’
tolu |
| Tongan notation | 3
to |
4
fa |
5
ni |
6
‘o |
7
tu |
8
va |
9
hi |
3’
to |