Meet your guitar

Every guitar rests on a very simple idea: a string stretched tight between two points. Pluck it and it swings back and forth hundreds of times a second, and that vibration reaches your ears as a note. Pluck the thickest string on your guitar and let it ring until it fades. It should sound like this:

Play: The open 6th string

If you look closely while it rings, you'll see the string blur, wider in the middle than at the ends. The string doesn't vibrate in just one way: it vibrates as a whole and, at the same time, in halves, in thirds… That blend is what gives each instrument its colour.

The guitar's two fixed points are the nut, next to the headstock, and the saddle, on the bridge. Now press the same string at the 12th fret, exactly halfway between them, and play it. The vibrating part is half as long and the note sounds much higher, yet "the same": it is the same note, one octave up.

Play: 6th string open and at the 12th fret

Follow a string from one end to the other. The parts appear in the same order in the illustration:

Every fret you move towards the body shortens the string a little and raises the note one semitone, the smallest step in Western music. Listen to the 6th string climbing fret by fret, from 0 to 12:

Play: 6th string, frets 0 to 12

String 6, Fret 3: G2 · 1 · Scale tone

Notice two things on your guitar:

• The frets get closer together as you move towards the body. That's no whim: to go up a semitone you always shorten the string by the same proportion, and the same proportion of a shorter string is a smaller distance.
• The 12th fret sits exactly halfway between nut and saddle. That's why it gives the same note as the open string, one octave higher, and why it carries the double inlay.

Theory deep diveThe maths of frets

In the tuning system we use (equal temperament), each semitone multiplies the frequency by the twelfth root of 2, $\sqrt[12]{2} \approx 1.0595$. Since a string's frequency is inversely proportional to its length, each fret leaves the vibrating string divided by that same number. Twelve frets later, the string has been divided by 2: half the string, double the frequency, one octave.

On a guitar with a 650 mm scale length (the distance from nut to saddle, typical of a classical), the first fret sits about 36.5 mm from the nut and the 12th fret at 325 mm. Luthiers work out the distance $d_n$ from the nut to fret $n$ with this formula, where $L$ is the scale length:

$$d_n = L \left(1 - 2^{-n/12}\right)$$

Check it: with $L = 650$ mm and $n = 12$, $d_{12} = 650 \times (1 - \tfrac{1}{2}) = 325$ mm.

There are countless models, but almost all of them belong to three families:

The big difference is how the sound is born:

• On an acoustic or classical, a string alone barely moves any air: you'd hardly hear it. Its vibration passes through the saddle and bridge into the top, a thin sheet of wood that vibrates like a speaker cone and moves a lot of air. The body and soundhole reinforce the low notes in particular.
• On an electric, the steel string vibrates above the pickup: a magnet wrapped in thousands of turns of copper wire. Moving inside the magnetic field, the string generates a tiny current that travels down the cable to the amplifier, which plays it through a speaker.

You'll go over this again at the tab stop, but it's worth locking in now: strings are numbered from the thinnest (1) to the thickest (6). And each one, played open, has a note name. In standard tuning, from the 6th to the 1st:

String 6, Open: E2 · 1 · Scale tone

The two outer strings share a name, E, but the 1st sounds two octaves higher than the 6th. Listen:

Play: 6th and 1st strings: low E and high E

Two guitars can look alike, yet one practically plays itself and the other is torture. It's nearly always down to two things:

• The gauge of the strings, that is, their thickness. It's measured in thousandths of an inch, and sets are named after the first and last strings: on electric, 9–42 and 10–46 are typical; on acoustic, 12–53 ("light"). Lighter strings are easier to press; heavier ones give more volume and body. For classical guitars you choose the tension (normal or high).
• The action: the height of the strings above the frets, measured at the 12th fret. As a rough guide, on the 6th string it's usually around 1.5–2 mm on an electric, 2–2.8 mm on an acoustic and 3–4 mm on a classical. Too high and you'll have to squeeze hard and notes higher up will go sharp; too low and the strings will buzz against the frets.

Most guitarists fret with the left hand and pick with the right. If you're left-handed you have three paths, and all three are valid:

1. Play right-handed. Many lefties do this without trouble: the fretting hand needs a lot of dexterity too.
2. A left-handed guitar, built as a mirror image. The most comfortable option if playing right-handed feels very strange.
3. Flip a right-handed guitar over. Some famous musicians played like that, with the strings re-ordered or even upside down, but it means reworking the nut and makes learning from diagrams and teachers trickier.

On this journey we'll talk about the fretting hand and the picking hand instead of left and right, so it works for everyone. In Settings → Hand you can choose "Left-handed" so the portal's diagrams are drawn mirrored.

Practice

A tour of your guitar

5 min

1. With the guitar in front of you, point to each part from the illustration, from headstock to bridge, and say its name out loud.
2. Play each open string, from the 6th to the 1st, saying its number and note: "sixth, E; fifth, A…".
3. Check against the table. Repeat until you get them all right.

Goal: Point to and name out loud 11 parts of your guitar and the 6 open strings without looking at the table.

Practice

The 12th-fret octave

60 BPM5 min

Play each string open and then at the 12th fret (you don't need to press hard, though the action is higher there). Hear how the two notes "fit". One beat per note.

Goal: Every 12th-fret note rings clean and you recognise it as the same note as the open string, only higher.

Self-assessment

Between which two points does an open string vibrate?

AThe nut and the 12th fretBThe nut and the saddleCThe tuning pegs and the bridge

Which part of the guitar do you tune with?

AThe soundholeBThe tuning pegsCThe frets

What are the open strings, from the 6th to the 1st?

AE A D G B EBE B G D A ECC D E F G A

Why does an electric guitar need an amplifier?

ABecause its steel strings move a magnetBBecause the magnetic pickup turns the string's vibration into an electrical signal, and that signal has to be amplifiedCBecause its body is hollow

If your guitar is very hard to press, what's the most likely cause?

AThe strings are too lowBThe strings sit very high above the fretsCThe gauge is very light

Listen: the 5th string open and then at the 12th fret. What do you hear?

Listen

AThe second is the same note, one octave higherBThe second is a different, lower noteCThey're exactly the same note at the same pitch

Optional reinforcement in the portalPrint the guitar anatomy sheet from the visual library(opens in a new tab)