ABC music notation is a plain-text format used for notating music. It was developed in the early 1990s by Chris Walshaw to provide an easy-to-read and easy-to-write format for notation down traditional tunes of Western origin; nowadays it is employed for a wide range of musical styles. With ABC notation, you can notate everything from folk to classical music.

Because ABC notation is plain text, it is also easy to share and distribute via email, websites, and other digital platforms. This has led to the creation of large online collections of traditional tunes in ABC notation, which can be accessed and downloaded by musicians all over the world.

ABC notation is based on a set of symbols that represent different musical elements, including notes, rhythms, and articulations. It also supports the notation of chords and lyrics, making it a popular format for folk and popular music.

Here is an Irish tune by Paddy O’Brien notated with ABC:

```
X: 1
T: Bubbling Wine
R: reel
M: 4/4
L: 1/8
K: Edor
|:BE~E2 d2^cd|BE~E2 ADFA|GBEF GABd|g2fg edBA|
B=cBA GBdB|A2^GB ADFA|BE~E2 GBe^c|dBA=c BE~E2:|
|:Be~e2 gebe|Ad~d2 fdad|Beed efge|fgaf gfef|
g2fg edB^c|defe dBA=c|BE~E2 GBe^c|dBA=c BE~E2:|
```

And here is the corresponding score:

As you see, it takes just a few simple lines of text to produce nice-looking scores!