Ten Parent Scales
There are a total of twelve main pitches (Shruti) in an octave, and to create a musical theme, specific frequencies from those twelve are chosen. These chosen pitches determine whether a song is sad/happy, slow/fast, and so on.
Since melody is prime and central to Indian music, we always look for pitch combinations that offer significant melodic potential. These are called ragas, and we know of about 500 ragas in the Indian Classical tradition.
Ragas | Raga classification
Ragas are classified in various ways. One system is to classify them under Ten Parent Scales, known as “Thaat”. These are similar to modes in ancient Greek music. Unlike ragas, which are more flexible in the number of notes they can include, Parent Scales are always heptatonic and must include one each of the seven notes (swara) – sa, re, ga, ma, pa, dha and ni. Variations arise due to the different variants (natural, flat, or sharp) used.
In Bhatkhande’s system, the basic mode of reference is that which is equivalent to the Western Ionian mode or major scale (called Bilawal thaat in Hindustani classical music). The flattening or sharpening of pitches always occurs with reference to the interval pattern in Bilawal thaat. This is how ten parent scales or Thaats are created. Each thaat contains a different combination of altered (vikrit) and natural (shuddha) notes. In any seven-tone scale (starting with Shadaj, Re, Ga, Dha and Ni can be natural (shuddha, lit. “pure”) or flat (komal, lit. “soft”) but never sharp, whereas the Ma can be natural or sharp (tivra, lit. “fast”) but never flat, making twelve notes as in the Western chromatic scale. The sharp tones are called Tivra Vikrit and flat tones are called Komal Vikrit swara (vikrit, lit. “altered”). Selecting seven tones in ascending order, where Sa and Pa are always natural whereas five other tones (Re, Ga, Ma, Dha and Ni can be present only one of their two possible forms, results in 32 modes which are known as thaats. Out of these thirty-two possibilities, Pt. Vishnu Narayan Bhatkhande ji chose to highlight only ten Thaats or scales.
In effect only heptatonic scales are called thaats. Pandit Bhatkhande ji applied the term thaats only to scales that fulfil the following rules:
- A thaat must have seven tones out of the twelve tones [seven natural, four flat (Re, Ga, Dha,Ni), one sharp (Ma)]
- The tones must be in ascending sequence: Sa Re Ga Ma Pa Dha Ni.
- A thaat cannot contain both the natural and altered versions of a note
- A thaat, unlike a raga, does not have separate ascending and descending lines
- A thaat has no emotional quality (which ragas, by definition, do have)
- Thaats are not sung but the ragas produced from the thaats are sung
One can arbitrarily designate any pitch as Sa (the tonic) and build the series from there. While all thaats contain seven notes, many ragas (of the audav and shadav type) contain fewer than seven and some use more. A raga need not to use every tone in a given thaat; the assignment is made according to whatever notes the raga does contain
Note that Thaats only give a rough structure of the raga that gives the ‘Chalan’ or way of singing of the raga.
The Ten Thaats (Scales)
- Bilawal: All pure notes
S R G M P D N
- Kalyan: Madyam tivra or the higher variant of Madhyam. Rest are pure notes. S R G M’ P D N
- Khamaj: Komal Nishad or Lower variant of Nishad. All other six are pure notes. S R G M P D n
- Bhairav: Rishabh and Dhaivat are Komal. Rest are pure.
S r G M P d N
- Kafi: Komal Gandhar and Nishad or the lower variants of Gandhar and Nishad. Rest are pure.
S R g M P D n
- Asavari: Gandhar Dhaivat and Nishad are Komal. Rest are pure notes.
S R g M P d n
- Bhairavi: Rishabh, Gandhar, Dhaivat and Nishad are Komal. Rest are pure.
S r g M P d n
- Marwa: Rishabh Komal and Madhyam Teevra.
S r G M’ P D N
- Poorvi: Rishabh, Dhaivat Komal and Madhyam Teevra.
S r G M’ P d N
- Todi: Rishabh, Gandhar, Dhaivat are Komal and Madhyam Teevra.
S r g M’ P d N
PS: Lower case alphabet denotes the lower variants of a specific note eg R – Shudh R
r- Komal R Teevra M is denoted as M’