Chord diagrams are the most common visual shorthand for learning new chords, and understanding their conventions is essential. On a standard diagram, vertical lines represent the six strings, and horizontal lines represent the frets. The thinnest string (high E) is string 1 and is drawn on the far right, while the thickest string (low E) is string 6 on the far left — this matches the way the strings appear from the player's viewpoint.
Above the nut line (the top horizontal line), two important symbols give string-by-string information. An "X" above a string tells you to skip or mute that string entirely — it should not sound when you strum. An "O" means play that string open, with no finger on it. Frets below the nut are numbered beginning with the space between the nut and the first metal fret wire as the 1st fret, and the count increases as you move toward the body. If a chord is positioned higher up the neck, fret numbers inside or beside the diagram tell you which fret the diagram starts at.
Inside the diagram itself, black dots show exactly where to place your fingertips, positioned in the open space between fret wires. Many diagrams include numbers inside or below the dots to indicate which finger to use: 1 is the index, 2 the middle, 3 the ring, and 4 the pinky. A curved line — or a thick bar — that spans multiple strings at the same fret indicates a barre, the technique of pressing one finger flat across several strings simultaneously. This is the visual cue for movable barre chord shapes and is one of the most important symbols to recognize.