This article is written by Toru Hoshino, a jazz bassist and instructor based in Japan who teaches online lessons to students worldwide. In this article, he explains why “just default to the 3rd, then the 5th” isn’t quite the right way to think about building a bass line.
Here’s an exchange I had with a student recently. While working on building a bass line, I asked, “what were you thinking about there?” and got this answer:
“I played the root, and then just kind of used the 3rd, then the 5th…”
Using chord tones like the 3rd and 5th is genuinely important when building a bass line, so the instinct isn’t wrong. But reaching for them just “kind of” — without a reason — doesn’t feel very musical.
Ideally, you’d be thinking more like:
- “The 3rd has this kind of color…”
- “The 5th has this kind of color…”
- “Which one actually fits this song?”
and choosing deliberately from there.
Contents
The Basics of the 3rd and 5th
Here’s the general rule of thumb:
- The 5th: adds harmonic thickness to the chord. It’s the same whether the chord is major or minor (the 5th of both C major and C minor is G).
- The 3rd: changes depending on major or minor (the 3rd of C major is E; the 3rd of C minor is E♭). Because of that, it carries much more of the chord’s emotional color — bright versus dark, and so on.
This might be hard to picture in words alone, but here’s a concrete example: when I’m playing a bossa nova bass line, I lean toward the 5th much more than the 3rd.
That’s because I found that leaning on the 3rd too much makes the note’s character too assertive — it ends up clashing with the relaxed, understated vibe that bossa nova calls for.
On the flip side, when I’m playing a jazz phrase, working the 3rd into the first beat of a bar more often gives the harmony a stronger, more assertive, cooler quality.
Being conscious of these different roles, and choosing accordingly, makes it much easier to bring real expression to both your bass lines and your solos.
Knowing the theory behind the 3rd and 5th is one thing — actually hearing which one fits a given song is exactly the kind of judgment a teacher can sharpen fast.
Want Personalized Feedback on Your Playing?
This is exactly the kind of thing that’s hard to fix alone — and where having a teacher makes all the difference.
At Line on Bass, I offer an online lesson service where you send me a video of your playing, and I give you specific, detailed feedback — every single day if you want.
Students from around the world are using this to fix exactly these kinds of issues and steadily improve their jazz bass skills.