A Thaat is a parent scale. Raags are derived from the Thaats. Thaat system categorizes the Raags by defining the positions (sharp or flat)of notes. A Thaat cannot be sung or played. A Thaat is just a theoretical ‘Sumpooran’ (Heptatonic) scale.
A musicologist Lochan Kavi developed the first Thaat system in the 15th century. In his book ‘Raag-Trungini’, he writes that at that time there were nearly 16000 Raags mentioned in the old books, stories, and myths, that Lord Krishna’s ‘Gopees’ (he had 365 Gopees) sang for him. Lochan Kavi found that out of all those mentioned, only 36 Raags had distinct scales. Thus he categorized all known Raags to 12 ‘Males’, the Sanskrit word for Thaat.

Then a Southern musicologist Pundit Venkatmukhi, used a mathematical formula to create 72 Thaats. He divided the Octave into two tetra-chords and applied the following rules:

1. Every Thaat must use ‘Sa’ (the keynote or the first note)
   2. Every Thaat must have 7 notes.
   3. Every Thaat must use notes from the upper and lower half (tetra-chords).

If you follow these three rules, it creates 72 unique scales. As hard as it sounds, this method is actually very easy to understand (eventually I will write a post about this).

Unfortunately it didn’t make much sense in the Northern Music, where notes were getting popular in their modern position (same as western notes, with a minimum interval of a semitone). Finally a modern musicologist Pundit Vishnu Narayan Bhatkhunday chose 10 out of the 72 southern Thaats and made them standard ‘10 Thaats of Northern Indian Music‘.

A few things you should know about a Thaat:
These are the amended Thaat rules that musicologist Pundit Vishnu Narayan Bhatkhunday adopted for the Hindustani music.

1. Every Thaat has all and only seven notes. That is one of every note in an octave. If ‘C’ is your ‘S’ (Sa or the keynote), then every Thaat must have all seven ‘C, D, E, F, G, A, B,’ (S, R, G, M, P, D, N) notes.
2. The Flat and Sharp notes (Komal and Tivar) separate one Thaat from another.
3. A Thaat cannot be played, so it doesn’t have to be written in ascending and descending patterns.
4. A Thaat does not have to sound pleasant to ears as it does not contain any rules to play the notes.
5. All Ten Thaat are named after a famous Raag from that Thaat. As ‘Marva’ is a Thaat and it is named after ‘Marva’ Raag, which is the most famous Raag from this Thaat.

In the next post we will see these 10 Thaats and understand how they relate to one another.

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