For many years I used the tri-tone chord progression — in fact it was one of my favorite chord substituions — but I didn’t know what it was called. I thought of it as a way to “slide in” to the next chord — a smooth way to move from one chord to another. And lots of my bass player friends used it too — but no one called it the tri-tone progression.

I have a cousin who teaches music in a major university with a PHD in music history, so after not seeing him for lots of years I asked him over dinner what the name of the progession I use all the time is…

You guessed it — the tri-tone substitution.