Score navigation, and the order the music is read in

A two-page score can last five minutes, and the difference is the navigation marks: signs that say "go back", "skip", "go to the end". They exist because music repeats far more than the page has room to write, and reading them is a skill separate from reading the notes.

The repeat barline

Two dots before a double barline say: go back to the beginning, or to the previous repeat barline, and play it all again. It is the simplest and commonest mark; an eight-bar section between two repeat barlines is sixteen bars of music.

Unless told otherwise, you repeat once. "Repeat three times", when it appears, says the number in words.

First- and second-time bars

When the repeat ends differently from the first time, the ending gets two time bars: the first, played on the first pass, and the second, played on the return, skipping the first. They are written as numbered brackets over the bars.

The reading is: play to the end of bar 1, go back, play again to the start of bar 1, skip it, go into bar 2 and carry on. It is where most beginning readers get lost, and the remedy is to pencil in the route before playing.

Da capo, dal segno and coda

Three Italian instructions cover the larger jumps:

• D.C., da capo, "from the head": go back to the first bar.
• D.S., dal segno, "from the sign": go back to the sign, a symbol like a crossed S, placed where the return should start.
• al Fine, "to the end": after the return, stop where Fine is written.
• al Coda, "to the coda": after the return, on reaching the coda sign — a circle crossed by a cross — jump to the coda, the separate closing passage marked with the same sign.

So "D.S. al Coda" means: go back to the sign, play to the coda sign, and jump to the coda. Three jumps in a four-word instruction, and that is how a song with an A A B A form and an ending of its own fits on one page.

Form written as a route

Navigation marks are musical form written as an itinerary. A verse-and-chorus song with three verses is written once, with the repeat barline and the time bars handling the returns; an A A B A form is written with the A once, a repeat, the B, and a D.S. that hands it back to the A with the coda at the end. Reading the marks is reconstructing the form; and whoever knows the form in advance reads the marks before needing them.

In the circle

In popular music played by ear, none of this is written and all of it happens. The form is agreed in words before starting — "head, two solos, head, and the ending repeats" — and the score's marks, when there is a score, only confirm the agreement. It is the same navigation without signs: whoever can read the signs can agree the form, and the other way round.

What to take from here

Repeat barlines go back to a point, first- and second-time bars handle different endings, and da capo, dal segno, fine and coda command the larger jumps in four Italian words. Together they are the piece's form written as a route, and reading them before playing, in pencil, is what separates a fluent reading from one that stops at the first return.