6 String Freedom

Part 6: Let chords guide your first solo · Lesson 049 / 117

Roman numerals describe chord relationships

Today’s one thing

Read a progression independently of its absolute key.

Roman numerals label chord roots by scale degree. Uppercase is used here for major triads, lowercase for minor, and a small circle for diminished. In a major key, the diatonic family is I–ii–iii–IV–V–vi–vii°.

In C major, I is C, IV is F, V is G and vi is Am. These labels let us describe a chord progression as a relationship rather than a list tied permanently to C.

Notice that a Roman numeral describes a whole chord, while a plain scale-degree number describes a note. The two systems are related, but do not substitute one for the other in an explanation.

Keep the four numerals I, IV, V and vi as today's playing vocabulary. Read the full family as a reference, not another set of shapes you must memorise before making music.

Hear it

Cfgc

Audio file

Four-beat count-in · 60 BPM · Warm sampled electric guitar. Listen once before playing along.

A concrete example

C–F–G–C in C major is I–IV–V–I. C–Am uses I–vi. Lowercase vi records that the chord on degree 6 is minor.

Fretboard view

High E (string 1) is the top line, matching guitar tablature. Select a note to hear it.

Root / tonicChord toneTargetChanged / colour noteOther note
I, IV, V and vi in C major
C = I, F = IV, G = V, Am = vi.
Guitar fretboard diagram: I, IV, V and vi in C major. High E string on top, frets 0 to 3. Notes C, F, G, A.
These dots mark chord-root note names, not the full chord shapes. The numerals describe the chords.
Play notes from a larger button list

One small map at a time. Hear the notes, then play the example without looking.

Try it, slowly

  1. Name I, IV and V in C.
  2. Write the numerals under C–F–G–C.
  3. Use G major to work out I, IV and V there: G, C and D.

Check one idea

Would IV always mean F?

Show the explanation

No. It means the major chord on degree 4 of the stated key. IV is F in C major, but C in G major.

A good place to stop

You can interpret a numeral using the stated key rather than treating it as an absolute chord name.

Return to the example after a short break. A clear explanation matters more than speed.