Which string · From Zero to Mozart

Most notes, you choose which string to play them on. Sometimes the part chooses for you — with a word, or with a Roman numeral. And the Roman numerals are a genuine trap.

Two notations, one instruction

On the page	Means
sul G, sul D, sul A, sul E	play this passage on the named string
Roman numeral I – IV near the notes	the string, counted from the top

Counted from the top:

Numeral	String
I	E — the highest string
II	A
III	D
IV	G — the lowest

So "sul G" and "IV" are the same instruction. A dashed line after the marking shows how long to stay there.

Why a composer marks it

Two reasons only: colour (a melody on the G string is dark and rich — Bach's Air on the G String is the famous case), or practicality (keeping a fast run on one string so you're not crossing back and forth). If neither applies, the string isn't marked and you pick.

Hear it

80 bpm

'sul D' — every note on the D string, the A taken with a 4th finger rather than the open string. All one colour, warm and even, and no crossings to smooth over.

80 bpm

The same phrase with no string marked. Now the A is the open string — brighter, and with a little crossing bump on either side of it. Neither reading is wrong; the marking is how the composer tells you which one they want.

Try it

Try

Play G–A–G–F♯ with the A as the open string — feel the bow hop over and back. Now play it again sul D, the A taken with your 4th finger, the bow staying on one string the whole time. Listen to the second version being smoother and darker. That's what a string marking buys.

The usual mistake

Reading III as "the third string from the bottom." It's the D string — third from the top. Count down from E every time until it's automatic. And ignoring a sul G on a passage that's easy to play up high on a bright string — you'd be throwing away the exact dark colour the composer asked for.