The II-V-I, Tonic, Dominant, and Subdominant Explained for Bassists

This article is written by Toru Hoshino, an upright and electric bassist and instructor based in Tokyo, for bassists who want to understand

the II-V-I

and

Tonic, Dominant, and Subdominant

Understanding what these mean and how they work will make analyzing a tune much faster.

I covered how to analyze a tune in this article, and getting faster at analysis means you can look at a chart and put together a bass line or an improvised solo more quickly too, which is especially useful if you’re:

Tonic, Dominant, and Subdominant, Explained

Let’s try playing a bass line over a progression like this.

Example 1

That doesn’t really feel like it “ends,” does it? It feels like the tune is going to keep going.

Example 2

Now what about this one — doesn’t this feel like it actually comes to a rest?

Example 1 has that unresolved, hanging feeling — like something’s left unfinished.

Example 2 has a settled, resolved feeling — like things have wrapped up cleanly.

Looking at it in terms of chords:

Ending on the chord G7 creates that unresolved feeling (Example 1).

And arriving at the chord C△7 creates that resolved, settled feeling (Example 2).

The role that G7 plays here — creating that unresolved, hanging feeling — is called the “dominant.”

The role that C△7 plays — creating that resolved feeling — is called the “tonic.”

And then there’s a third role: a chord that’s neither as unresolved as the dominant nor as settled as the tonic — somewhere in between. That’s called the “subdominant,” and here that’s the Dm7 chord.

The last 3 bars of this example move:

subdominant ▸ dominant ▸ tonic

and this particular motion is widely considered very pleasant to the ear, and gets used constantly in jazz and pop music.

Since saying “subdominant, dominant, tonic” every time is a mouthful, this motion gets a shorthand name: the “II-V-I.”

What Is a II-V-I?

This builds directly on the diatonic chord chart.

Key	I△7	IIm7	IIIm7	IV△7	V7	VIm7	VIIm7(♭5)	Key Signature
C	C△7	Dm7	Em7	F△7	G7	Am7	Bm7(♭5)	None
G	G△7	Am7	Bm7	C△7	D7	Em7	F♯m7(♭5)	1 sharp
D	D△7	Em7	F♯m7	G△7	A7	Bm7	C♯m7(♭5)	2 sharps
A	A△7	Bm7	C♯m7	D△7	E7	F♯m7	G♯m7(♭5)	3 sharps
E	E△7	F♯m7	G♯m7	A△7	B7	C♯m7	D♯m7(♭5)	4 sharps
B	B△7	C♯m7	D♯m7	E△7	F♯7	G♯m7	A♯m7(♭5)	5 sharps
F♯	F♯△7	G♯m7	A♯m7	B△7	C♯7	D♯m7	E♯m7(♭5)	6 sharps
C♯	C♯△7	D♯m7	E♯m7	F♯△7	G♯7	A♯m7	B♯m7(♭5)	7 sharps
F	F△7	Gm7	Am7	B♭△7	C7	Dm7	Em7(♭5)	1 flat
B♭	B♭△7	Cm7	Dm7	E♭△7	F7	Gm7	Am7(♭5)	2 flats
E♭	E♭△7	Fm7	Gm7	A♭△7	B♭7	Cm7	Dm7(♭5)	3 flats
A♭	A♭△7	B♭m7	Cm7	D♭△7	E♭7	Fm7	Gm7(♭5)	4 flats
D♭	D♭△7	E♭m7	Fm7	G♭△7	A♭7	B♭m7	Cm7(♭5)	5 flats
G♭	G♭△7	A♭m7	B♭m7	C♭△7	D♭7	E♭m7	Fm7(♭5)	6 flats
C♭	C♭△7	D♭m7	E♭m7	F♭△7	G♭7	A♭m7	B♭m7(♭5)	7 flats

Going back to that subdominant ▸ dominant ▸ tonic motion, and applying it to the diatonic chords:

The 2nd chord is the subdominant
The 5th chord is the dominant
The 1st chord is the tonic

So:

The motion subdominant ▸ dominant ▸ tonic is what’s called a 2-5-1, or “II-V-I.”

That said, when you change key, the tonic and dominant chords change along with it, as shown below.

Key	1st (Tonic)	2nd (Subdominant)	5th (Dominant)
C	C△7	Dm7	G7
G	G△7	Am7	D7
D	D△7	Em7	A7
A	A△7	Bm7	E7
E	E△7	F♯m7	B7
B	B△7	C♯m7	F♯7
F♯	F♯△7	G♯m7	C♯7
C♯	C♯△7	D♯m7	G♯7
F	F△7	Gm7	C7
B♭	B♭△7	Cm7	F7
E♭	E♭△7	Fm7	B♭7
A♭	A♭△7	B♭m7	E♭7
D♭	D♭△7	E♭m7	A♭7
G♭	G♭△7	A♭m7	D♭7
C♭	C♭△7	D♭m7	G♭7

Looking at the table above:

In the key of F, Gm7 is the 2nd chord, C7 is the 5th chord, and F△7 is the 1st chord

In the key of G, Am7 is the 2nd chord, D7 is the 5th chord, and G△7 is the 1st chord

An Easier Way to Think About the II-V-I

The II-V-I is a lot easier to grasp if you think about it visually, on the bass neck.

Take Dm7 ▸ G7 ▸ C△7. That motion looks like this on the neck…

  or like this…

Take Gm7 ▸ C7 ▸ F△7, and that motion looks like this…

…or like this.

Take Am7 ▸ D7 ▸ G△7, and that motion looks like this…

…or like this.

Once you see it this way, it’s a lot easier to recognize and react to on the fretboard.

What’s the Point of Knowing About the II-V-I?

You might be thinking: “Okay, I get the theory behind the II-V-I, but what do I actually do with it?”

Once you recognize a progression as a II-V-I, you can reuse material you’ve already worked out.

This is especially useful if you’re someone who struggles to come up with a bass line or a solo on the spot just by looking at the chord symbols.

Reusing a Bass Line

Say you worked out a bass line like this over a progression like this one.

A bass line used in tunes like “But Not for Me”

The chord motion used here — Fm7 → B♭7 → E♭△7 — shows up constantly in jazz tunes.

So I took this exact same bass line and dropped it directly into a different tune.

A bass line used in tunes like “It Could Happen to You”

In theory, this same bass line works over this tune’s progression too.

You’ll still want to actually play it and check whether it fits the feel of the tune, but once you can reuse material like this, you can work through tunes more efficiently and react a lot faster.

So that’s the rundown on tonic, dominant, subdominant, and the 2-5-1, aimed at bassists.

I hope it’s useful for your daily practice.

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