Interval Inversions

The NANDI Method locates intervals on non-adjacent strings using the natural interval relationships between the open strings. Instead of memorizing fretboard shapes, use these relationships to identify the nearest interval and its inversion through simple fretboard logic.

Major Seconds ↔ Minor Sevenths

Major 2ⁿᵈs occur between:
1-2 • 2-3 • 4-5 • 5-6 • 6-7

Their inversions are Minor 7ᵗʰs:
2-1 • 3-2 • 5-4 • 6-5 • 7-6

Reference string pairs:
Major 2ⁿᵈ: A→B • D→E • G→A
Minor 7ᵗʰ: B→A • E→D • A→G

Any two notes on the same fret of these string pairs share the same interval relationship.

Check out the lesson titled  “Inversion Basics“.

Minor Seconds ↔ Major Sevenths

Minor 2ⁿᵈs occur between:
7-1 • 3-4

Their inversions are Major 7ᵗʰs:
1-7 • 4-3

Minor Thirds ↔ Major Sixths

Minor 3ʳᵈs occur between:
7-2 • 3-5 • 6-1 • 2-4

Their inversions are Major 6ᵗʰs:
2-7 • 5-3 • 1-6 • 4-2

Reference string pairs:
Minor 3ʳᵈ: E→G • B→D
Major 6ᵗʰ: G→E • D→B

Any two notes on the same fret of these string pairs are related by the same interval.

Major Thirds ↔ Minor Sixths

Major 3ʳᵈs occur between:
5-7 • 1-3 • 4-6

Their inversions are Minor 6ᵗʰs:
7-5 • 3-1 • 6-4

A major 3ʳᵈ is simply one fret higher than a minor 3ʳᵈ on the same string pairs.

Perfect Fourths ↔ Perfect Fifths

Perfect 4ᵗʰs occur between:
7-3 • 3-6 • 6-2 • 2-5 • 5-1 • 1-4

Their inversions are Perfect 5ᵗʰs:
3-7 • 6-3 • 2-6 • 5-2 • 1-5 • 4-1

Reference string pairs:
Perfect 4ᵗʰ: E→A • B→E
Perfect 5ᵗʰ: A→E • E→B

The notes found on the same fret of these string pairs are always a perfect 4ᵗʰ or perfect 5ᵗʰ apart, depending on the direction.

The NANDI Method replaces interval-shape memorization with the natural relationships between the strings.

Major 2ⁿᵈ ↔ Minor 7ᵗʰ
Minor 2ⁿᵈ ↔ Major 7ᵗʰ
Minor 3ʳᵈ ↔ Major 6ᵗʰ
Major 3ʳᵈ ↔ Minor 6ᵗʰ
Perfect 4ᵗʰ ↔ Perfect 5ᵗʰ

Once these five relationships are understood, interval locations on non-adjacent strings can be derived using simple fretboard logic rather than memorized shapes.