I don't expect you to have many writings on your wall, but you could (or should?) write and remember this again:
To get a 7th Chord, move the Middle Finger down 2-steps .
Let's try A7, we will derive from A-chord, of course.
The finger hit the nut? Leave it an open string! A7 is:
If this is A (it really is),
then A7 is:
E7 should be simple. Starting from E:
Final E7:
In pictures, E-chord and E7 respectively:
At this point, pause and ponder. How many chords you can derive now? See how many of the listed chords you can figure out. HINT: Proceed one step at a time. Say A#m7: start from A, derive A#; from the A# position: derive minor(m) to get A#m; from A#m position: derive 7th to get A#m7.
A,Am,A7,Am7
B,Bm,B7,Bm7
C,Cm,C7,Cm7
D,Dm,D7,Dm7
E,Em,E7,Em7
F,Fm,F7,Fm7
G,Gm,G7,Gm7
A#,A#m,A#7,A#m7 / Bb,Bbm,Bb7,Bbm7
C#,C#m,C#7,C#m7 / Db,Dbm,Db7,Dbm7
D#,D#m,D#7,D#m7 / Eb,Ebm,Eb7,Ebm7
F#,F#m,F#7,F#m7 / Gb,Gbm,Gb7,Gbm7
G#,G#m,G#7,G#m7 / Ab,Abm,Ab7,Abm7
At this point, pause and ponder. How many chords you can derive now? See how many of the listed chords you can figure out. HINT: Proceed one step at a time. Say A#m7: start from A, derive A#; from the A# position: derive minor(m) to get A#m; from A#m position: derive 7th to get A#m7.
A,Am,A7,Am7
B,Bm,B7,Bm7
C,Cm,C7,Cm7
D,Dm,D7,Dm7
E,Em,E7,Em7
F,Fm,F7,Fm7
G,Gm,G7,Gm7
A#,A#m,A#7,A#m7 / Bb,Bbm,Bb7,Bbm7
C#,C#m,C#7,C#m7 / Db,Dbm,Db7,Dbm7
D#,D#m,D#7,D#m7 / Eb,Ebm,Eb7,Ebm7
F#,F#m,F#7,F#m7 / Gb,Gbm,Gb7,Gbm7
G#,G#m,G#7,G#m7 / Ab,Abm,Ab7,Abm7
