Understanding Parent Scale or Thaat

Thaat

A thaat is the parent scale in Hindustani classical music, serving as a framework for classifying various ragas. 

It's a seven-note scale, chosen from the 12 total notes in an octave, that provides the foundational melodic structure for a family of ragas.

Types of Thaats

The modern classification system, developed by musicologist Vishnu Narayan Bhatkhande, recognizes 10 main thaats that encompass almost all ragas. 

Each thaat has a specific combination of shuddha (natural), komal (flat), and teevra (sharp) notes.

1. Bilawal (बिलावल): Uses all shuddha notes. It's considered the base or natural scale. (Notes: Sa, Re, Ga, Ma, Pa, Dha, Ni)

2. Kalyan (कल्याण): Uses teevra Ma and all other shuddha notes. (Notes: Sa, Re, Ga, M′, Pa, Dha, Ni)

3. Khamaj (खमाज): Uses komal Ni and all other shuddha notes. (Notes: Sa, Re, Ga, Ma, Pa, Dha, Ni​)

4. Bhairav (भैरव): Uses komal Re and komal Dha. (Notes: Sa, Re​, Ga, Ma, Pa, Dha​, Ni)

5. Poorvi (पूर्वी): Uses komal Re, teevra Ma, and komal Dha. (Notes: Sa, Re​, Ga, M′, Pa, Dha​, Ni)

6. Marwa (मारवा): Uses komal Re and teevra Ma. (Notes: Sa, Re​, Ga, M′, Pa, Dha, Ni)

7. Kafi (काफ़ी): Uses komal Ga and komal Ni. (Notes: Sa, Re, Ga​, Ma, Pa, Dha, Ni​)

8. Asavari (आसावरी): Uses komal Ga, komal Dha, and komal Ni. (Notes: Sa, Re, Ga​, Ma, Pa, Dha​, Ni​)

9. Bhairavi (भैरवी): Uses all four komal notes: Re, Ga, Dha, and Ni. (Notes: Sa, Re​, Ga​, Ma, Pa, Dha​, Ni​)

10. Todi (तोड़ी): Uses komal Re, komal Ga, komal Dha, and teevra Ma. (Notes: Sa, Re​, Ga​, M′, Pa, Dha​, Ni)

These 10 thaats simplify the classification of thousands of ragas, making it easier for students to learn and organize the vast repertoire of Hindustani music.