How Do You Fill the Space Between Chord Tones? Connect the 3rds First
The notes between chord tones are not filler — they are scale notes hung on a skeleton, and the skeleton is the 3rd of every chord. In the online jazz guitar lessons at VoiceLid Jazz Guitar, Junewon Choi teaches the mechanism in one sentence: connect the 3rd of each chord to the 3rd of the next, cross through the 7th on the way, then fill the remaining gaps with scale steps — and save the target note for last. That final rule is the one most players miss. The note that announces the next chord loses all its power if you spend it early; place it at the end of the phrase and the line resolves like a sentence landing on its verb.
None of this is a private theory trick. It is how standard melodies were written — which is why the proof below comes from Fly Me to the Moon, not from a lick book.
Why start with the 3rd of every chord?
Because the 3rd is the note that tells you what the chord is — major or minor, bright or dark — and standard melodies land on it constantly. Draw a line through nothing but the 3rds of a progression and you already have a musical shape with direction, before you have improvised anything. Guide tones — the 3rd and 7th together — are the voice leading backbone that the whole Bridge Series is built around: two notes per chord that move by step and carry the entire harmonic story. The skeleton is small on purpose. You can hear it, sing it, and aim at it in real time, which is exactly what a scale run through seven equal notes never gives you.
What goes between the 3rds — and in what order?
Work outward from the skeleton, one layer at a time:
Connect the 3rds. Play only the 3rd of each chord through the progression.
Cross through the 7th. On the way from one 3rd to the next, touch the current chord's 7th — 3rd, 7th, next 3rd.
Fill the gaps with scale notes. Stepwise motion between the anchors.
Save the target for last. The next chord's 3rd is the destination — do not leak it early.
That is the entire mechanism. The art is in step 4: everything before the target builds expectation, and the target pays it off.
Where does the Fly Me to the Moon melody fit in?
Take Fly Me to the Moon in C and mark the 3rd of every chord. Now look at the melody: it walks from 3rd to 3rd, crossing through the 7th, with the spaces between filled by plain scale steps. The famous opening line is the skeleton with scale-note fill, descending. Reverse the direction of that exact concept and you are writing your own ascending line with the same DNA. This is why Junewon calls melody the first improvisation teacher: the tune already demonstrates the mechanism, slowed down and sung. For the fuller version of that argument, see What Notes Do You Play in a Jazz Solo? The Melody Already Drew the Map.
What about a progression like Em–Am–Dm–G in C?
A viewer asked exactly this, and it exposes a subtlety: not every chord accepts the same decoration. Over the iii chord (Em in C), the 9th — F# — sounds foreign, because F# is outside the key of C. The reason is historical: in classical harmony, the iii chord mostly appeared as an inversion of the tonic — a I chord wearing different bass — so it wants tonic sound, not fresh tension. Treat Em as a tonic-family color, connect its guide tones cleanly to Am, and the line sits inside the key instead of fighting it. The skeleton method quietly protects you here: 3rds and 7ths are always safe; tensions need a context check.
Why can't I just learn someone else's lines?
Because the gaps are where your sound lives. Junewon compares it to writing an essay: the night before it's due, you discover that assembling other people's points doesn't produce your thousand words — you have to cut, choose, and connect until the argument is yours. Same fretboard, same deadline. Two students given this identical skeleton never play the same solo, because the fill choices — which scale step, which rhythm, which direction — come from everything each player has ever heard. Exploring those combinations note by note is slow, and it is the entire point. For a related take on borrowed vocabulary, see Connecting Thirds: Is It Okay to Use Bebop Vocabulary?.
When you are ready to build this skeleton-first approach into a complete soloing system, the Fundamentals Program walks it through real tunes, step by step.
About the Author
Junewon Choi is a Berklee-trained jazz guitarist and the founder of VoiceLid Jazz Guitar, an online education platform teaching jazz harmony and improvisation through the Functional Diagonal Approach (FDA) — a chord-first method built on voice-leading rather than scale boxes.
Wes' Insight — Wes Montgomery's fretboard logic, in lesson form
Fundamental 1: Wes Diagonal System — the FDA from the ground up