Who this is for
Players who know the chords of a key and want fresh options when a progression feels stale or too plain. Already swap chords by ear? Test out on Day 5.
Best done after: Colour Your Chords, Chords in a Key. It is advice, not a rule: every lesson has short "rusty on…?" boxes for anything you skipped.
Why learn this
A **substitution** replaces a chord with another that does the same job, so the song still makes sense but sounds different. It is the quickest way to freshen a progression, and it is how jazz players re-imagine the same tune a hundred ways.
The key idea is that chords have **jobs** (home, away, tension), and chords that share a job can swap. Everything here is a suggestion: if you like how it sounds, it is right, and swapping back is one chord away.
What you will be able to do
- Same-job swaps: I, vi and iii; IV and ii
- Secondary dominants: a mini V in front of any chord
- The ii–V move
- The tritone substitution
- How to audition a swap by ear
The 5-day plan
- Same job, different chord. Swap chords that do the same job: I, vi and iii; IV and ii.
- Secondary dominants. Put a dominant 7th in front of a chord to point at it.
- The ii–V move. Put a ii chord in front of a V to make the classic ii–V.
- The tritone swap. Swap a dominant 7th for the one a tritone away, and know why it works.
- Test day: swap and listen. Show you can identify chord jobs and the moves that substitute for them.
How each session works
Every day follows the shape of a workout. It starts with a warm-up that reviews earlier days, then technique: a short, plain explanation with a small interactive tool to try it on. Then come the working sets, drills with instant feedback, and a finisher, a short test with a pass mark so you only build on things you can do. A cool-down recaps the day and previews the next.
Choose your split
The daily split is a session a day: done in a week. The easy split is a session every other day, with rest days between: two weeks, and a gentler pace. On your own pace there is no schedule. Nothing is ever locked, and you can change split at any time.
Frequently asked questions
How do I know a substitution will work?
If the new chord shares most notes with the old one (or does the same job), it will usually work. Then listen: your ear is the final test, especially against the melody.
Is it still the same song?
Usually yes: the melody and the overall shape stay, so people recognise it. Changing one chord at a time keeps it recognisable.
What is a secondary dominant?
A dominant 7th chord that points at a chord other than home. A7 pointing at Dm is the dominant of Dm: it borrows the pull of V and puts it on ii.
Do I need to know jazz?
No. These tricks appear in pop, soul, gospel and folk as well. The jazz names (tritone, ii–V) are just labels for useful ideas.