Just Enough Theory
No piling up terminology — just what playing-and-singing actually uses: note names, keys, and where chords come from.
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The 12 notes
Music cycles through 12 notes: C C# D D# E F F# G G# A A# B, then back to C. Two adjacent notes are a “semitone” apart, and one octave is exactly 12 semitones. On the guitar, every fret you move is one semitone.
The major scale (do re mi)
The major scale follows the interval pattern “whole whole half whole whole whole half.” Start on C and walk that pattern, and you get the C major scale's do re mi fa sol la si — all white keys, no sharps or flats.
C Minor pentatonic · The first position for rock / improv — learn this one first
Red = root, orange = scale notes; open-string notes sit to the left of the nut (the thick line on the far left). Tap any note to hear it, or press "Play scale" to hear one octave ascending from the root. Switch the labels to "Degree" to see the relative intervals; change the root or scale and you'll see the same position shape slide as one along the fretboard — that's the heart of the five scale positions.
On the fretboard map, set the scale to “major scale” and the root to C, and watch how do-re-mi-fa-sol-la-si spreads across the fretboard; switch to “note name” labels and you can confirm that “every fret is one semitone” — abstract theory suddenly something you can see and hear.
How chords are “stacked” up
On the scale, skip a note and stack three notes together, and you get a triad. Because the intervals stacked differ, you get the difference between major triads (bright) and minor triads (soft, dark). Stack one more note and it becomes a seventh chord.
- 💡 Theory is in the service of your ears and your hands — play it and hear it first, then circle back to the theory, and it'll click much faster.
Practice checklist
- On the 1st string, go up fret by fret from open and count out the 12 semitones back to the same-named note.
- Name the 7 notes of the C major scale (do through si).