7. Chords and strumming

▶ Open in Aratu to hear and change the examples

A progression is written as a lead sheet, on a line called chords. The rule of sharing works one level up: chords that share a bar divide it equally.

Try it▶ Hear it in Aratu

chords = | Am | F | C G | Am _ _ G |

C and G take half a bar each; Am lasts three beats and G one. The shares must fall on the beats: three chords in a 4/4 bar would split it between beats, so Aratu asks how long each lasts.

Chord symbols keep their usual spelling: Am, F, G7, Cmaj7, Dm7b5, E/G#, and the spellings of a Brazilian cifra too: C7M, Bº, G7(b9). C6/9, E7alt and solfège roots work as well: Lám, Sol7, Fa#m7, Dó/Mi. N.C. (or -) is a bar with no chord.

Strumming. A line called strum uses the rhythm rules with guitar symbols:

Symbol	Meaning
`d`	strum down
`u`	strum up
`m`	muted strum (a chuck)
`g`	a golpe, a tap on the guitar's top (flamenco), no strings
`t`	a down strum and a golpe together
`-`	the hand passes without striking
`_`	let it ring
upper case	accented strum

Try it▶ Hear it in Aratu

guitar {
  chords = | Am | F | C G | G |
  strum  = D du -u du
}

The strum repeats every bar and the chords change on their own. A down strum sounds the strings from low to high a few milliseconds apart, an up strum from high to low; accents strum harder and faster. Without a strum, the chords play whole, like a keyboard.