Hi Nacho,

You’re right, it’s a typo.
It should be i ii III iv v VI VII (minor – diminished – major – minor – minor – major – major)
A diminished chord is constructed of minor third intervals, so it’s notated as a lowercase.

In the second example:
i ii III iv V7 VI VII
The 5th scale degree is treated as a dominant 7th chord which gives you a perfect cadence when going from the V to the i chord.
A perfect cadence is a progression from V to I in major keys, and V to i in minor keys, where the V is the dominant 7th chord.
The V7 chord has a very strongly pull towards to the tonic, which makes for a perfect cadence.

Both chord sequences are used for a natural minor scale.

First: When you wrote
“… minor – diminished – major – minor – minor – major – major
Often notated as Roman numerals: I – ii – iii – IV – V – vi – vii …”
Isn’t the tradition to use Upper Case for mayor chords, and lower case for minor?
Wouldn’t be more accurate to write i – II – III – iv – v – VI – VII ?

Second:
I was searching about minor chord progressions last night and found this chord formula for the natural minor scale:
i – II dim – III – iv – V7 – VI – VII

Is it wrong? is it other minor scale?

Thanks mate, you rock.

Hi Srikumar,

Check out these posts for great recommendations:

https://guitarfirstchord.com/the-best-high-quality-affordable-acoustic-guitars/

https://guitarfirstchord.com/10-best-affordable-acoustic-guitars-under-200-dollars/

Best regards,
Klaus Crow