Theory
Through yesterday, the 3rd split bright (major) from dark (minor). Today we handle a new axis, the 7th — specifically the b7 (minor 7th). Add one b7 to a major chord and you get a dominant 7 (e.g., G7). The name sounds grand, but the job is the same as yesterday: just laying one note on.
The essence of a dominant 7 is, in a word, tension. Unlike a major chord that sits there comfortably, once the b7 comes in there's a pull — "I want to go somewhere, I want to resolve fast." That wriggling blues-guitar feel, the stickiness of funk, the thrill of jazz — it all comes from this one b7. Isn't that wild? One note plants a "want to go" into the chord.
On the fretboard, lower yesterday's G major 4th string, fret 5 (R=G) to fret 3 (b7=F) and you have G7 — leaving the 3rd (3rd string, fret 4, B) alone, moving only the 4th string two frets down. Now this week's picture snaps into focus — 3rd string = the 3rd (bright/dark) switch, 4th string = the 7th (tension) switch. Just two strings, two switches. Tomorrow you'll combine them to make four chords at will. Today, just lock in this one 4th-string switch.
See it
G7 (E-form) — only the 4th string dropped from fret 5 to 3. The green is the freshly added b7 (F), the source of the tension.
Example 1 — the add-the-b7 line. Fret the chord's skeleton (R·3·5), then add the b7 (F) at the end. Listen for the moment the b7 turns the sound from "finished" into "unfinished — curious what's next."
▶ BPM 72. Stable through "root-3rd-5th," then catch the slight "tilt" at the final b7 (F). Repeat 4×.
Example 2 — Major → 7 switch comp. Bar 1 G, bar 2 G7. On each marked note strum the whole chord, but the only thing that moves is one finger on the 4th string (fret 5 → 3). That one fret turns stability into tension.
▶ BPM 78, repeat 4×. Bar 1 stable G → bar 2 itchy G7. Only the 4th-string finger drops from fret 5 to 3. Enjoy that "want to go somewhere fast" feeling on G7.
Today's practice
0–10 min · Warm-up Alternate G ↔ G7 every four beats. Move only the 4th-string finger between fret 5 and 3, keeping the 3rd (3rd string, fret 4) fixed. Check that both chords ring cleanly on all six strings.
10–20 min · Brain training (today's target = b7) Fret Example 1 and name R·3·5·b7 aloud, then isolate just the b7 (F) at the 4th string, fret 3, over and over. You pass once you can land the b7 with eyes closed. This is your "tension switch" for the week.
20–40 min · Real comping (Example 2 / 75–85 BPM) Repeat Example 2 at BPM 78 4× — bar 1 G, bar 2 G7. Once comfortable, move just the root to the 5th string (e.g., C ↔ C7) and apply the same switch. If you have a blues backing track, lay it on top. The goal is to feel the b7's push-and-pull in your hands.
40–50 min · Record & reflect (recommended) Record 30 seconds of G ↔ G7. Check: does the b7 ring clearly (not dead) on G7, and does the switch stay clean?
Done when: you can switch G ↔ G7 using only fret 5↔3 on the 4th string, and fret the b7 with your eyes closed.
- Confusing b7 and R. On the 4th string, fret 5 is R (G), fret 3 is b7 (F). If you mix them up, remember "need tension → drop it (5→3)."
- Lowering the 3rd too. Today, only the 4th string. Leave the 3rd string (the 3rd) alone so it stays a "major-family 7." Lower the 3rd as well and that's the m7 you'll learn tomorrow.
- Mistaking tension for a "wrong sound." G7's "unfinished" feeling isn't a bug, it's a feature — that lack of resolution is what pulls you to the next chord.
- Flat, no palm mute. Honor Example 2's ghost hit to keep the groove alive.