Dec 2025
Playing in a Key: Music Theory Basics
Build chords from the major scale to get the chords "in a key"
Key Takeaways
- Build chords from the major scale to get the chords "in a key"
- The pattern: 1, 4, 5 are major / 2, 3, 6 are minor / 7 is diminished
- A "2-5-1" means playing the 2nd, 5th, and 1st chord of any key
- In C: 2-5-1 = Dm - G - C
- In G: 2-5-1 = Am - D - G
- The pattern stays the same in every key
Transcription
Today we're going to talk about playing in a key, which is useful for guitar players and anyone interested in music theory.
Lay out a major scale and build chords from it. Those chords will be either major or minor, and there's a specific pattern that's the same in every key.
The pattern: 1, 4, and 5 are major chords. 2, 3, and 6 are minor chords. 7 is diminished (we'll deal with that later).
When musicians talk about a "2-5-1" chord progression, they mean playing the 2, 5, and 1 chord in any key.
In the key of C: the 2 chord is D minor, the 5 chord is G, the 1 chord is C.
In the key of G: the 2 chord is A minor, the 5 chord is D, the 1 chord is G.
The pattern of chords in a key works in any key, and the pattern stays the same.
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