The Interval Pattern Of Fourths: The NANDI Method

Watch the companion YouTube lesson below before continuing.

On a single string, intervals are easy to see because they progress one fret at a time. For example, the 12 scale degrees of the chromatic scale can be played on one string from the root to the octave.

Seeing these same intervals across all six strings is much more difficult. The NANDI Method solves this by organizing interval numbers into a pattern of fourths that mirrors the guitar’s tuning, allowing you to recognize intervals through patterns instead of memorization.

Why Fourths?

The guitar is tuned primarily in perfect fourths, making fourths the natural way to organize the fretboard.

Rearranging the 12 interval numbers into fourths produces the following sequence:

1, 4, ♭7, ♭3, ♭6, ♭2, ♭5, 7, 3, 6, 2, 5, 1

 

 

Two Connected Patterns

 

 

 

 

 

The sequence is made up of two related groups.

Flat Pattern
1 → 4 → ♭7 → ♭3 → ♭6 → ♭2 → ♭5

Natural Pattern
7 → 3 → 6 → 2 → 5 → 1 → 4

Notice that 7-3-6-2-5 appears twice:

• Once as ♭7-♭3-♭6-♭2-♭5
• Once as 7-3-6-2-5

Finding Fourths from the Root

Using the major scale (1-2-3-4-5-6-7), the natural intervals follow a simple path through the fourth pattern.

 

 

To locate the fourth from the root, count five chromatic intervals:

1 → ♭2 → 2 → ♭3 → 3 → 4

Whole-Step Shortcut

Instead of counting every interval, notice the repeating whole-step movement between pairs.

1–4 → move down one whole-step → ♭7–♭3

♭7–♭3 → move down one whole-step → ♭6–♭2

♭6–♭2 → move down one whole-step → ♭5–7

7–3 → move down one whole-step → 6–2

6–2 → move down one whole-step → 5–1

This repeating movement generates the complete fourths pattern.

Applying The Pattern To The Fretboard

Use the mnemonic:
One Forsaken Tree Set To Fire → 1-4-7-3-6-2-5

Apply the sequence across the strings. When crossing to the B string, move one fret higher to maintain the fourth pattern.

Natural Intervals Only

If you only want to visualize the natural intervals of the major scale, use:

7 – 3 – 6 – 2 – 5 – 1 – 4

Mnemonic:

Severed Tree Sticks To Fight On For.

 

Starting from the 7ᵗʰ, located one fret below the root, the pattern continues across the fretboard using the same fourth-based logic.

The Main NANDI Principle

Rather than memorizing individual note locations or scale shapes, the NANDI Method organizes intervals into a repeating pattern of fourths. Once this pattern is understood, the fretboard becomes a connected map where notes, intervals, scales, and chords can be decoded through relationships instead of rote memorization.