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Chord progressions · Reverse lookup

The G – C – G – D – C – G chord progression

The chords G – C – G – D – C – G are the 12-bar blues — the Roman-numeral pattern I – IV – I – V – IV – I — read in G major.

Hear G – C – G – D – C – G in G major
Version
Notation
C1C2C3C4GBC5DC6C7C8
I›G
80 BPM
Root-position blocks move in leaps. Voice leading holds the common tones and steps the rest —

The chords

Every chord links to its full reference page — notes, keyboard diagram, audio, fingering, and inversions.

Which key is it in?

A progression's key is the one whose scale contains all of its chords, and the Roman numerals below are each chord's job in that key. When several keys qualify, the ear usually decides by where the music comes to rest.

KeyRoman numeralsNamed pattern
G majorI – IV – I – V – IV – Ithe 12-bar blues
E minor♭III – ♭VI – ♭III – ♭VII – ♭VI – ♭IIINot a named pattern

Why the 12-bar blues works

The 12-bar blues reduced to its harmonic skeleton — four bars of I, two of IV, back to I, then the signature V–IV–I turnaround home. Play every chord as a dominant 7th for the true blues color.

The full the 12-bar blues reference → covers variations, songs built on it, and the pattern in every key.