Theory
Here's why we're doing this today — nail one chord properly and dozens of minor chords come free. Yesterday you fixed the 3rd (B) in G major into your eye, right? Today you touch only that 3rd. One finger, one fret. The rule is a single line:
Lower the 3rd a half step (3 → b3) and Major becomes minor.
On the fretboard, drop the 4th fret (B, the 3rd) on the 3rd string one fret down to the 3rd fret (B♭, b3). One finger, one fret, and the chord's expression flips from bright to sad. R and 5 — you don't touch them at all.
At first it might feel almost anticlimactic — "wait, that's really it?" — and that emptiness is normal. Good principles are simple like that. Bright vs. sad is always decided by one note, the 3rd; today you just feel that once, in your hands.
Why it matters: from now on, for any chord you meet, just ask "where's the 3rd, and is it major or minor?" and you instantly know whether it's a bright or dark chord. Instead of memorizing 60 shapes, you track one spot: the 3rd. Am, Cm, Fm — you'll make them yourself, thinking "ah, just drop the 3rd a half step."
See it
First, G minor (E-form) — yesterday's G major with only the 3rd lowered a half step. See the 3rd string move from fret 4 to fret 3. The green is that b3 (B♭), today's star.
Example 1 — the 3 → b3 compare line. On the same 3rd string, play fret 4 (major 3rd, B) next to fret 3 (minor 3rd, B♭) and catch the emotional difference that half step makes.
▶ BPM 70. "Root → major third → minor third → root." Feel the expression darken the instant the 3rd drops to b3. Repeat 4×.
Example 2 — Major ↔ minor switch comp. Same rhythm, bar 1 is G, bar 2 is Gm. On each marked note strum the whole chord, but notice that the only thing that actually moves is one finger on the 3rd string (fret 4 ↔ 3).
▶ BPM 75, repeat 4×. Bar 1 is bright G, bar 2 is dark Gm. The rhythm is identical; only the 3rd-string finger drops one fret. Let your hand remember that one fret changes the whole mood.
Today's practice
0–10 min · Warm-up Alternate G ↔ Gm every four beats. Move only the 3rd-string finger between fret 4 and 3, keeping the other fingers planted as much as possible. Don't let the switch stutter.
10–20 min · Brain training (today's target = b3) Fret Example 1 while saying "third / flat third" aloud. You pass once you can alternate fret 4 and fret 3 on the 3rd string accurately with your eyes closed. This one fret is your "minor switch" for the whole week.
20–40 min · Real comping (Example 2 / 70–80 BPM) No backing track needed. Repeat Example 2 at BPM 75 4× — bar 1 G, bar 2 Gm. Once comfortable, move just the root to the 5th string (e.g., C ↔ Cm) and apply the same switch. The key is to switch by thinking "I lowered the 3rd," not by re-grabbing a shape.
40–50 min · Record & reflect (recommended) Record 30 seconds of G ↔ Gm. Check: does another string die during the switch, and does the b3 ring clearly? If it mushes, stand the 3rd-string fingertip up more.
Done when: you can switch G ↔ Gm smoothly using only fret 4↔3 on the 3rd string, and fret the b3 with your eyes closed.
- Re-grabbing the whole hand. Trying to reshape the entire hand for minor is slow. Only one 3rd-string finger, one fret. Leave the rest planted.
- The b3 won't ring. If the 3rd string's fret 3 dies, a neighboring finger is leaning on it. Stand your fingertip up so only the 3rd string sounds.
- Memorizing "the sad chord shape." Don't memorize Gm as a shape. Remember it as "G with the 3rd lowered a half step," so it works identically at A, C, D — anywhere.
- Touching the 5th too. The 5th (D) doesn't move today. If a finger drifts to the 5th, the chord wobbles.