
A guitar chord diagram is a simple map of the fretboard. Vertical lines are the strings, horizontal lines are the frets, dots show which notes to press, and small marks above the grid tell you which strings to play open or skip. Read it left to right from the lowest string to the highest and the shape is unambiguous.

A chord name tells you the notes; a diagram tells you where to put them. A C major chord is the notes C, E, and G — and a chord finder shows you those notes, the intervals that build them, and the diagram or piano shape to play. That bridge from name to shape is the fastest way to learn an unfamiliar chord without hunting through a paper chart.
Most chords are stacks of thirds from a root note. A major triad is the root, a major third (4 semitones up), and a fifth (7 semitones up) — bright and resolved. A minor triad lowers that third by a semitone, which darkens the mood. Add a seventh on top and you get the richer chords of jazz, blues, and R&B.
| Chord | Notes (from C) | Quality |
|---|---|---|
| C major | C E G | Bright |
| C minor | C Eb G | Darker |
| C7 | C E G Bb | Bluesy / dominant |
| Cmaj7 | C E G B | Soft, jazzy |
Reading single chords is the first step; the music happens when you string them together. Once a few shapes are comfortable, a chord progression tool shows how the chords in a key move from one to the next.
Vertical lines are the strings (low E on the left to high E on the right) and horizontal lines are the frets. Dots show where to press, numbers on them say which finger to use, an O means play the string open, and an X means do not play it.
They sit above the strings. An O means play that string open with no finger pressing it; an X means mute or skip that string so it does not sound when you strum.
A major chord has a major third — 4 semitones above the root — and sounds bright. A minor chord lowers that third to 3 semitones above the root, which makes it sound darker or more melancholic.
Use a chord finder: type the chord name and it shows the constituent notes, the intervals, and a playable piano or guitar shape, so you can go from a name straight to something you can play.