Making Thaats with Tetrachords Part I

Ustad Mehdi HassanIn the last post, we looked at eight Tetrachords. As I mentioned in that post, these Tetrachords are holding the key to all musical scales. How easy is it? Just memorize eight groups of four notes and construct 32 Thaats on the fly. Review the Tetrachords once more here before proceeding.

Now let’s name these Tetrachords:

Natural scale “C D E F – G A B C” is ‘Bilaval’ in Indian music, and these notes are:

S R G m – P D N S*

When we assign a name to a Tetrachord, we assume that its counterpart is natural. So when we are naming Poorvang Tetrachords, we assume that Utrang is “P D N S*” or “G A B C;” and when we are naming the Utrang Tetrachord, we assume that the Poorvang is “S R G m” or “C D E F.”

Later we will cross match them to build different scales.Now have a look at these images along with the assigned names:

Poorvang Tetrachords:

1. Bilaval
2. Suryakant
3. Gauri Manohari
4. Kokilpirya

1. S R G m is Bilaval
2. S r G m is Suryakant
3. S R g m is Gauri Manohari
4. S r g m is Kokilpirya

Utrang Tetrachords:

1. Bilaval
2. Sarsangi
3. Khamaj
4. Charukeshi

1. P D N S* is Bilaval
2. P d N S* is Sarsangi
3. P D n S* is Khamaj
4. P d n S* is Charukeshi

Complete the scales by adding upper or lower natural (Bilaval) Tetrachord as needed. > Music Theory > Advanced Theory

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