Modern Indian music is based on ‘Mail’ or ‘Thaat’ system. The ancient music was based on Gram and Moorshana. A Moorshana is the order of seven consecutive notes in any Gram. The modes of western music are exact equivalent of Moorshanas.
Before we explore Moorshanas, let’s see the Seven modes of western music.
In western music, if we change the tonic of a natural scale, the modes changes. We can say that according to ancient Indian music, the Moorshana changes, where in modern Indian music, the Thaat changes. Here are the seven modes:
1. Ionian I = C D E F G A B
2. Dorian II = D E F G A B C
3. Phrygian III = E F G A B C D
4. Lydian IV= F G A B C D E
5. Mixolydian V = G A B C D E F
6. Aeolian VI = A B C D E F G
7. Locrian VII = B C D E F G A
Six of the above modes have equivalent Thaats within the ten Thaats of Modern Hindustani Music.
1. Ionian is Bilaval
2. Dorian is Kafi
3. Phrygian is Bhairvi
4. Lydian is Kalyan
5. Mixolydian is Khamaj
6. Aeolian is Asavari
Read more about Thaats here (Thaat system) and here (Ten Thaats of Northern Indian Music).
The idea to play the intervals determined by a mode or a Moorshana from a fixed note (such as C), gave birth to the Thaat theory. In this theory, all the above modes will be written like this:
1. Ionian I = C D E F G A B (all natural)
2. Dorian II = C D Eb F G A Bb (2nd and 7th flat)
3. Phrygian III = C Db Eb F G Ab Bb ( 2nd, 3rd, 6th and 7th flat)
4. Lydian IV= C D E F# G A B (4th sharp)
5. Mixolydian V = C D E F G A Bb (7th flat)
6. Aeolian VI = C D Eb F G Ab Bb (3rd, 6th and 7th flat)
7. Locrian VII = C Db Eb F F#(Gb) Ab Bb (2nd, 3rd, 6th and 7th flat, both positions of 4th)
There is no Locrian Thaat in modern Indian music, because in Thaat system, we must use one of all seven notes. As notes are assigned in northern music, there is no Pa or fifth is this mode. According to Thaat system, this is a Chhadav Scale (hexatonic). However, according to the Moorshana system, this is a Sampooran Scale. This mode is Dhaivitaad Moorshana of Shadaj Gram. There is no Thaat for Dhaivataad Moorshana in modern Northern Music.
There are 56 Moorshanas in 2 Grams that are constructed exactly the same way as we constructed modes in the above example.