Now let’s talk about Tony Iommi, boys and girls. This man is a self-confessed heavy metal blues guitarist, and that phrase right there tells you everything you need to know about his style. He didn’t invent heavy metal—not by himself—but he sure shaped it into something that changed music forever.
The secret to Tony’s sound isn’t complicated. It’s actually rooted in blues, just like everything else in guitar. He takes pentatonic minor scales—the same scales Muddy Waters and Howlin’ Wolf played—and he adds chromatic passing notes. Those little connecting notes between the major notes of the scale give his riffs that creepy, unsettling feeling that makes Black Sabbath so heavy.
Understanding Chromatic Pass Notes
Here’s the thing about chromatic pass notes: they’re the notes between the notes you’re already playing. In the E pentatonic minor scale, you’ve got E, G, A, B, D. But there are black keys and half-steps between those notes. Tony uses them to create tension and texture.
The two most important chromatic passes in Tony’s vocabulary are between the 4 and 5 (that’s the augmented 4th or flatted 5th—sometimes called the “devil’s note”), and between the 7 and 8 (that’s the raised 7th from the harmonic minor scale). These aren’t random notes. They’re tools.
The B Minor Riff at the 7th Fret
Let’s work in B minor, which is where this riff lives. Everything starts at the 7th fret. You’re gonna play the low E string—the 6th string—at the 7th fret three times. Use your first finger, nice and controlled. Three times on that same note. That’s your foundation. That’s the heartbeat of the riff.
From there, move your pinky up to the 10th fret on that same 6th string. You’ve just jumped from B up to D#. Now cross over to the 5th string. You’re moving to the 7th fret, the 8th fret, and the 9th fret in sequence. Down-up picking, steady as a drum. Then cross to the 4th string and repeat the same pattern: 7th, 8th, 9th.
Watch Your Finger Placement
Here’s where it gets interesting. When you’re crossing strings, you need to be thinking ahead. Your first finger is gonna stay at the 7th fret while your middle finger hits the 8th and your pinky hits the 9th. You’re creating a little ladder as you move across the strings. It looks complicated, but once you get it under your fingers, it becomes automatic.
The beauty of this approach is that it works the same way on every string. So if you mess up and need to start over, you’ve got that same pattern to fall back on. Tony’s genius wasn’t in inventing something impossible. It was in taking simple patterns and stacking them in a way that sounds huge.
The Chromatic Connection
Those pass notes between 7-8 and 8-9? That’s what makes this riff distinctly Tony. A blues player might skip them and just hit the major notes. But Tony lets your ear hear every step of the journey. It creates this creeping, crawling quality—like something’s coming at you in the dark.
And that’s the whole philosophy right there. Tony took what the blues taught him and made it heavier, darker, more intense. That’s not a betrayal of the blues. That’s a continuation of it. Every generation of guitar players does this. We learn what came before, and we push it further.
If you’re exploring heavy metal and rock guitar riffs, you’ll see this chromatic passing note technique show up again and again. It’s foundational stuff.
What’s Coming Next
We’ve got the basic building blocks down. But Tony’s got more tricks. In Part 2, we’re gonna look at the root-six pentatonic climb—another signature move that’ll show you how versatile this approach really is. Stick around, boys and girls.
