I am studying substitute chords,
and secondary triads with two common notes can substitute primary triads.
I know that a chord, in which the root and third notes are common, has a stronger surrogate function.
However, I saw an explanation on the Internet Wiki (Korean) that the chords that substitute different chords depending on major and minor. it is as below
ii - Secondary chords / Secondary chords substitute subdominant chords, and correspond to Re, Fah, and R in the name of the commandment. In general, the form of the first dislocation is widely used.
iii - Represents a third chord / dominant chord, and corresponds to mi, sol, and si in the name of the command.
vi - It represents the sixth chord / tonic chord, and corresponds to Ra, Do, and Mi in the name of the command.
vii° - There is no 7th chord / surrogate chord, and according to the name of the command, it corresponds to Si, Re, and Pa. Since it is a reduced triad, the resonance of the basic position is unstable, so it is generally used in the form of the first potential.
All standards are in C major.
In minor, the direction of use of chords on the same intervals depending on the harmonic minor scale, natural minor scale, and melodic minor scale.
ii° - Secondary chords / Secondary chords substitute subdominant chords and correspond to Si, Re, and Pa in the name of the commandment.
III+ - Represents the third chord / dominant chord, and corresponds to do, mi, and sol♯ in the name of the command. Since it is an augmented triad, I tend to use 'do' as a non-harmonic consonant and resolve it with V rather than being used independently.
III5♮ - 3rd chord / Tonic chord, and corresponds to do, mi, and sol in the name of the command.
VI - 6th chord / It Secondary chords substitute subdominant chords, and according to the name of the commandment, it corresponds to F, D, and Do. Only when used in the deceptive cadence, it substitutes for the tonic chord.
vii° - There is no 7th chord / surrogate chord, and it corresponds to sol♯, si, and re according to the name of the command.
♮VII - 7th chord / 'Once' represents the dominant chord, and corresponds to sol, si, and re in the name of the command. However, rather than maintaining the functionality within the minor key, it tends to be used as a V in the major key when the harmonious flow is converted into the context of a parallel major key.
All standards are A minor.
What I'm particularly confused about here is that VI is described as a substitute for subdominant in minor, so why is it different from major?