What is 123?

ABC is a well-supported method for expressing musical notation in text, i.e. with note letter-names.

Using ABC notation, and in the key of C, Mary Had a Little Lamb might go: ED CD EE E .

If, like Sister Maria, you use solfege, which can be used in "key-agnostic" ("movable Do") mode, then the song would go: Mi Re Do Re Mi Mi Mi .

My 123 notation is also key-agnostic, and gets parsed into ('boils down to') ABC. In 123, the song would go: 32 12 33 3. This 123 site lets you enter / edit 123, and you can either use the default key, or you can specify a key from several choices.

The included sample songs range from simple use of 123 to more-complex use. Try using the Load Sample dropdown to select and then play the one called 'kids'.

Or, to check out my original goal on this site, try loading the 'twelve' sample, click Rainbow, and then 'Infinite Play and Shuffle'.

(NB: Not-so-simple constructs, such as triplets or duplets, may play more accurately in the 'Notation' player than in the 'Rainbow' player.)