Jazz music theory is a bucket of so many fascinating and expansive concepts that give jazz musicians all of the musical tools they need to contribute to an ensemble, and improvise to their heart’s content.

There are so many dimensions to the concepts within jazz music theory - understanding how chords are structured gives you the framework to craft compelling solos, but really knowing how to swing gives you the ability to find the pocket (groove) and sing with your instrument.

In this post, we’ll walk you through everything you need to know to get started: how to read a lead sheet, how jazz chords are constructed, basic scales for improvisation, common progressions, and more.

Before we begin, let’s watch this excerpt from renowned jazz pianist Jeremy Siskind’s tonebase course on jazz theory:

While this post goes over all of the basics, Siskind’s course really takes you a level deeper into all of these concepts.

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How to read a lead sheet

Lead sheets are the foundational notation of a jazz standard.

In its simplest form, a lead sheet is sheet music, containing a single melody line with chord symbols above it. The musicians are tasked with filling in the notes of the chords, the bass line, and the drum parts, followed by improvising solos. 

Think of it like a sketch or a blueprint. It contains the bare bones of the composition, and the performers must bring it to life. 

A lead sheet shows what is called one “chorus,” or statement of the melody. In a performance, the performers loop the chorus over and over again, playing the melody and taking turns improvising solos. 

Having a way of keeping track of choruses is essential for smooth transitions, so it’s every performer's job to keep track of the choruses as they pass by. Transitions and solo changes typically occur at the beginning of a new chorus.

Lead sheets, often found in real books, or printed collections of tunes, help musicians stay oriented while allowing space for self-expression. They allow musicians to improvise freely while maintaining cohesiveness with the rest of the band.

Lead sheets are also tools that musicians utilize to modify a piece of music to fit their needs. For instance, if you play a song for a specific event, you may need to extend or shorten it according to the circumstances.

Likewise, if you want to perform the same music as a solo or with a group, the lead sheet provides flexibility that conventional music notation cannot. This kind of adaptability, as it eradicates the necessity to turn innumerable pages of notated music, makes jazz performances more manageable and flexible. 

Let’s take a look at a lead sheet for one of the most popular jazz standards out there, Take the “A” Train:

There are other notational systems jazz players use, such as rhythmic notation or slash notation. Both imply some degree of freedom for the performer.

Rhythmic notation (pictured top) offers information about the rhythm, usually specifying only the harmony.

On the other hand, slash notation (pictured bottom) instructs artists to entirely invent their part, utilizing only the chord symbols and their musical awareness of the situation. 

Therefore, for melodic players, this suggests improvisation is required; for chord players, they are encouraged to accompany or "comp"; bass players will create their bass lines, and drummers are directed to play a drum groove in line with the instrument they play. 

These notational systems are commonly used in large bands, offering clarity for the performers while allowing for freedom. 

How to play swing

Among other things, swing is a musical style and rhythmic feel. 

Playing with a swing feel means dividing each beat into three parts, and playing eighth notes on the first and third parts of that three-part division. This is generally expected when playing in a swing style, which will be most of the time when playing jazz music. 

However, there are subtle variations in swing feel that make each player’s swing as unique as their fingerprint.

Understanding and mastering this rhythm, especially for a classically-trained player, can take some reprogramming, but is vital for achieving the desired sound.

Normally in swing, offbeats have more weight than downbeats, often resulting in a "do-VA do-VA" rhythm emphasis. Putting weight on the offbeats, especially in eighth notes, helps prevent the music from becoming too heavy or square. 

Additionally, musicians should familiarize themselves with elements of the drum set, such as the kick, snare, and hi-hat, as understanding their function can enhance the overall swing feel of the group.

In jazz music, the hi-hat and the ride cymbal are the foundation of the rhythm section. A drummer starts by activating the hi-hat with their foot on beats two and four (pictured top); these beats are the main indication of swing rhythm and act as our timekeeper. Additionally, the ride cymbal emphasizes the swung eighth notes, starting with one quarter note, followed by two eighths (pictured middle). 

Regardless of the instrument you play, try playing these two rhythms in unison by tapping your foot on the hi-hat while using your right hand for the ride cymbal on beats one, two, three, and four (bottom). 

One of the key elements of jazz performance is the anticipation of notes; this is where notes are played half a beat earlier. This anticipation is implemented both melodically and with chords. 

Lastly, unlike classical music, in jazz, the melody is expected to be slightly altered during performance, emphasizing the improvisational aspect of this genre.

Below are some examples of anticipation (moving a note earlier) and delay (moving a note later). Jazz musicians also commonly use features like grace notes, ghost notes or repeated notes to personalize melodies, turning the piece into their own creation. 

This transformation from a 'bare bones' melody to personalized musical expression is a vital aspect of turning a lead sheet into music. 

On a broader scale, understanding the chords commonly used in jazz music is paramount. The next step is to decipher these chords, recognize what scales could be used to improvise over them, and establish an efficient practice routine. 

How are jazz chords constructed?

Jazz is known for its intricate and complex chords, but today we’ll just look at three of the most important: the major seventh, minor seventh, and dominant seventh chords.

The major seventh chord comes from the first, third, fifth, and seventh notes of the major scale. In a C major seventh chord, E is the third, G is the fifth, and B is the seventh. Jazz has more dissonance compared to classical music, clearly demonstrated by the major seventh interval, which is considered a stable and consonant sound:

1. Major seventh chord

Possible chord symbols using C as the Root: Cmaj⁷, C^∆7

Three ways to find it:

• Select the first, third, fifth, and seventh notes of the major scale based on the root of the chord.
• Combine a major triad based on the root with a major seventh. The major seventh is the note one half step below the root.
• Stack intervals starting from the root. First, use a major third, then add a minor third, then another major third.

Sound: Bright but with a little more nostalgia than a simple major triad.

2. Dominant seventh chord

Possible chord symbols using C as the root: C⁷

Three ways to find it:

• Starting with a major seventh chord based on the root, lower the seventh by a half step.
• Combine a major triad based on the root with a minor seventh. The minor seventh is the note two half steps below the root.
• Stack intervals startings from the root. First stack a major third, then add a minor third, then another minor third.

Sound: tense, lie it wants to resolve. Familiar to those with classical experience.

You can form a dominant seventh chord either by starting with a major seventh chord and lower the seventh by a half step, or by adding the seventh two half steps below the root to a major triad.

Minor seventh chords, on the other hand, combine a minor triad with the same seventh as in a dominant seventh chord. The notes of the minor seventh chord are composed of the root, third, fifth, and seventh, but compared to a major seventh chord, the third and the seventh are each lowered by a half step. 

3. Minor seventh chord

Possible chord symbols using C as the root: Cm7, C-7, Cmin7

Three ways to find it:

• Starting with a major seventh chord based on the root, lower the third and the seventh by a half step.
• Combine a minor triad based on the root with a minor seventh. The minor seventh is the note two half steps below the root.
• Stack intervals starting from the root. First, stack a minor third, then add a major third, and another minor third.

Sound: not quite the melancholic sadness we associate with minor. A little ambivalent or undecided.

Remember, with minor seventh chords in jazz, everything gets an uppercase letter, and there are several symbols used, including a small "m," a minus sign, and "min."

Eventually, in your journey playing jazz, you will need to master the 2-5-1 chord progression, as it comprises about 75-80% of jazz harmony as a whole. The progression includes a minor seventh chord, a dominant seventh chord, and a major seventh chord. While this technically means mastering 36 different chords, the 2, 5, and 1 of a given key all come from that key’s major scale. 

It’s worth pointing out that the 2-5-1 (or ii-V-I) progression is named after the overall key, not the initial chord. So a 2-5-1 in C major begins with D minor but ends with C major.

Learn to recognize this progression in different pieces. The 2-5-1 progression reflects the circle of fifths (pictured below) which is fundamental to Western musical theory. 

Identifying 2-5-1 progressions is crucial not only to understand the structure of a given piece, but also to improvise using the proper scale, which we’ll explore in the next chapter.

Note: Remember that the key signature of a piece does not change the notes indicated by a chord symbol. So Cmaj7 always contains the same notes, regardless of the overall key signature.

2-5-1 progressions sometimes won’t resolve to their expected 1 chord. For instance, in the tune below (Satin Doll), Em7 to A7 is a 2-5 in D, even if we don't include the D major chord.

Furthermore, when dealing with major 7th chords, sometimes it’s more elegant to substitute the 7th of the major scale with the 6th to avoid dissonance, especially when the root note is featured prominently in the melody. Specifically, instead of playing C, E, G, B for a Cmaj7 chord, a pianist or guitarist will play C, E, G, A when there’s a C in the melody.

Practice finding 2-5-1 progressions and identifying chords to perfect these skills. Pieces like Clifford Brown's "Joy's Spring" that are full of 2-5-1 progressions and provide excellent practice material.

Practicing the ii-V-I progression

There are several different ways to conceptualize practicing the ii-V-I chord progression. It’s helpful first to internalize the chord tones of each chord (root, third, fifth, and seventh). 

You might begin simply by playing the roots of each chord: the ii, the V, and the I. Then add chord tones one at a time:

To practice the ii-V-I progression in all keys, it’s common to modulate in whole steps. This way, the major I chord becomes the minor ii of the next key. 

For example, if we start in the key of C and end on a C major 7th chord, we can change this to a C minor 7th chord, which is the ii in the key of B♭-major, a whole step below C. Repeating this technique, we can cover the keys: B♭, A♭, G♭, E, D, and back to C. Then, we start a half-step above or below C to cover the other sets of keys: D♭, B, A, G, F, and E♭. 

And etc.

Using this method of covering all 12 keys, we can begin to practice improvisation. Because all these chords come from the same major scale (of the I chord), you can use that scale for the entire progression.

However, if you want your improvisation to sound a bit more nuanced, it’s ideal to learn to think of each mode as separate. This way you highlight the chord tones more strongly.

For some, it’s easier to think of modes as how they relate to their major scale (D Dorian and G Mixolydian come from C Major). However, for others, it’s easier to craft D Dorian from other D scales, and G Mixolydian from other G scales.

The Dorian mode resembles its associated major scale but with a lowered 3rd and 7th (D Major with a lowered 3rd and 7th gives you D Dorian). The Mixolydian mode resembles its associated major scale but with just a lowered 7th (G Major with a lowered 7th gives you G Mixolydian). 

Pentatonic and blues scales

The pentatonic scale is a major scale stripped of the fourth and seventh notes. This leaves behind only five notes, eliminating the dissonance the fourth and seventh often cause, and leaving behind a more consistently pleasing sound.

It’s employed frequently in pop and rock, as well as folk music from around the world. Each major pentatonic scale has a corresponding relative minor pentatonic scale, with the same pitches but beginning on a different tone: 

Jazz takes the pentatonic scale a step further by adding an extra note between the third and fourth notes of the minor pentatonic scale, resulting in what is called the blues scale. 

This six-note scale has a variety of intervals. A significant characteristic of the blues scale is the presence of 'blue notes' - notes that clash with the dominant chord sound. 

For example, the C, D and D♯ in the A Blues scale all clash with an A dominant 7th sound, but they add depth and tension that you can’t get anywhere else. 

The notes of a blues scale in relation to the major scale are the root, flat 3rd, 4th, sharp 4, natural 5th, and lowered 7th. You can transpose this to any key, calling it the blues or minor blues scale, as it's built from the minor pentatonic.

An extra half-step between the second and third notes of a major pentatonic scale creates what's known as the sweet scale or major blues scale. Comparing the minor and major blue scales, you will notice the minor scale is darker and leans more towards dissonance, whereas the major scale is much more joyful.

Both minor and major blue scales can be used effectively over the 2-5-1 progression. Although certain notes in these scales create a lot of tension, if you resolve your phrases, they can work brilliantly. 

The best jazz musicians fluidly move between the different scales, creating different effects. Always keep in mind that you are not restricted to one scale, so mix them up and balance your playing – it’s all about reacting musically to whatever situation you find yourself in. 

Intro to jazz blues

The blues form in music is unique in that dominant chords are used as tonic sounds, and there is an unusual twelve-bar form. 

The form contains three phrases: the first one stays around the tonic chord, the second phrase departs from the tonic and goes to the IV chord before returning, and the third phrase visits the V chord before returning to the tonic chord. One could use a ii-V-I in the last four bars instead. 

The blues form is strongly correlated to the blues scale, and the blues scale can be fully used over the entire blues form. 

However, when using the major blues scale, one must be careful around the IV chord in the second line – the third scale degree of the major blues scale (A) likely won’t fit well over this B♭7. So it’s essential to use your ear carefully!

When playing this basic blues form, we can also use the corresponding Mixolydian scales for every chord. For F7, play F mixolydian, and so on... 

A more complex jazz blues in F may contain one chord per measure, or in other cases, multiple chords. This blues adds a diminished chord, which functions more like a passing chord in jazz (see the B diminished chord below, which contains the notes B, D, F, and A♭).

Next there’s an F dominant 7 over C, an inversion of F7 with C in the bass. Inversions are notated using a slash in jazz. Notice the bass note rising by half steps in bars 5 through 7.

Half-diminished chords like A-7♭5 are minor 7th chords with an additional flat 5th. They are not quite fully diminished chords, as these have a 7th which has been flattened twice. The chords marked with asterisks are slightly beyond the scope of this lesson, and will be explained in a future theory lesson! 

When improvising over blues forms, use the minor blues scale or the major blues scale with care. Use modes as well to create contrast!

Notice how, in bar 4, we have a 2-5 to B♭, so we play the modes of the B♭ major scale. However, we don’t arrive at a B♭ major chord, but a dominant chord, so we have to switch from B♭ major to a B♭ Mixolydian sound! This shift is what gives the jazz blues its unique character, though it requires special careful attention for the improvisor. 

To improve your improvisation skills, interact with musical accompaniments - whether a play-along video, or something like the iReal Pro app which allows you to choose your tempo and accompanying instruments. This allows you to listen and understand how each note fits within the harmony and rhythm of a piece.

Jeremy Siskind, who teaches the tonebase course this post is based on, recommends the “AAB blues” exercise, where you improvise a phrase for four measures, repeat it for the next four, and then conclude with a contrasting four-bar wrap-up phrase. This forces you to listen to yourself and play intentionally, making your practice more focused. Here’s an example of an AAB blues: 

Fill about two measures with music and leave about two measures for rest, enabling any performing companions to respond. This creates a musical call and response effect. Practice will make your improvisation sessions less overwhelming and more organized, and in the following sessions (to be released soon), we’ll look into ways to create more contrast, color, and details as you improvise on diverse and complex chord symbols.

Conclusion

And there you have it, all of the building blocks that make up the foundation of jazz music theory.

Hopefully you’ve not only learned the basic knowledge, but have also acquired several excellent practice resources to help you excel in your progress as a jazz musician.

And this is just the tip of the iceberg - there is so much more to learn about jazz music theory, and we’re excited for your journey. 

If you’re looking for the perfect resource to excel your progress as a serious musician, check out tonebase.

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