Second-inversion shapes

You've seen the root in the bass, then the 3rd in the bass. There's exactly one note left to put on the bottom: the 5th. That's second inversion — the third and final shape. Learn it and the trilogy is complete: one triad, three shapes, tiling the entire neck.

The 5th goes in the bass

Same three notes as always — root, 3rd, 5th. This time the 5th is lowest. For C major that's G on the bottom, then C, then E:

Read it bottom-up: G, C, E. Still C major. Notice the root now sits in the middle of the shape, on string 2 — a good landmark for finding this voicing fast. And notice we're up near fret 12: the three inversions climb the neck as you go, and this is the top of the climb.

Every role rotates one more string

Put all three shapes side by side and the pattern finishes a full loop. Each chord tone steps to the next string with every inversion, and after three steps it has visited all three strings:

So the quality switches land in their third and last position:

Across the three inversions, each role makes one complete lap of the three strings. The rules for building chords never changed — a small 3rd for minor, a shrunk or stretched 5th for dim or aug — only the string under your finger keeps moving.

The five triads in this shape

Every shape keeps the root fixed on string 2, fret 13. The changed note is called out in each caption.

Major

Minor — lower the 3rd on string 1

Sus4 — push the 3rd up to the 4th (string 1)

Augmented — raise the 5th on string 3

Diminished — lower both the 3rd (string 1) and the 5th (string 3)

Fret summary

Written low-to-high, bass first: string 3 · string 2 · string 1.

Bold cells changed from major. The middle note — string 2, the root — stays on fret 13 for all five. Move it and you change the key, not the quality.

Three shapes, one neck

Here's the payoff. The same C major chord shows up in three places as you climb, each starting the triad from a different note:

Root position   →   1st inversion   →   2nd inversion   →  (root position, one octave up…)
  ~fret 5             ~fret 8–9           ~fret 12–13
  bass = Root         bass = 3rd          bass = 5th

Overlay the three fret tables and every role turns a complete circle through the three strings:

Read down any column and you get one shape; read across any row and you watch a single note walk all three strings. Learn that rotation and you stop seeing three unrelated grips — you see one triangle repeating up the neck. Three notes × three inversions × twelve keys, and the whole fretboard is just this one shape, over and over.

• Because a chord now lives in three nearby spots, you can always reach the next chord without leaping — the basis of voice leading.
• Once the rotation is in your hands, you start to know what note sits on any of the top three strings at any fret. That's what "reading" the fretboard really means.

Play with all three shapes together on the interactive triad fretboard.

In one line: second inversion puts the 5th in the bass — the root moves to string 2, the major/minor switch to string 1, the dim/aug switch to string 3. Stack it with the other two and each chord tone circles all three strings: one triangle tiles the whole neck. Back to the start in movable triads and first inversion.