Without a doubt music is one of the most beautiful creations of human kind. Music has lived and evolved with us for more than 3000 years. Different geographies and cultures have developed their own forms of music. Despite of those cultural and geographical disparities there are striking commonalities in different forms of music.

When talking about world music, India enshrines a very rich repository and lots of different forms of music evolved over many years influenced by invasions, trade and cultural exchanges. The classical form of music in India has its roots dating back several thousand years. Since then it has been fused with many other forms of music. Today the classical music in India is largely divided in 2 categories 

Classical forms of music have also evolved independently in the west through several centuries molded by religion, migrations, renaissance and many other factors. Different composers have given different dimensions to harmonies, melodies and rhythms. Lot of melodic and rhythmic structures grew out, these structures have provided musicians a canvas and several tools to express their art.

Musicologists have come up with lot of systems and structures to classify music. Two specific structures of the Thaat system in the Hindustani classical form and the Mode system from the western classical form. Before that, for simplicity lets fix our key to C which means the Sa from Hindustani music will correspond to C in the western notation. The whole correspondence looks like the picture below. I’ve used an underline for komal swar or flat note and a dot over the character for teevra swar or sharp note.

The thaat system in Hindustani or North Indian style of music is accredited to Pandit Vishnu Narayan Bhatkhande who was an Indian musicologist in late 18th century. He came up with this classification system of thaat. Bhatkhande in my opinion was a genius in devising the thaat system who researched and traveled extensively to create this classification. His genius is revealed in the way he has classified the ragas and assigned them to different thaats.

As per Pandit Vishnu Narayan Bhatkhande : A Thaat is only a group of abstract tonal forms. A thaat can be imagined as a container or a parent scale for ragas. For example a specific group of notes is called Kalyan Thaat, raga hindol, kedar, yaman and many other ragas belong to this thaat. Pandit Bhatkhande created 10 different sets of notes which are called thaats.

The thaats are more than just the grouping it is also loosely tied to emotions and have their own character as well. Though ragas have the real power of generating and creating emotional values.

Modes in Western Classical form also known as church modes, they are a part of western music since the middle ages. Modes are inspired by the theory of ancient Greek music. Their traces are much older than the thaat system which was devised in early 1900s. A mode much like a thaat is a group of notes with certain melodic characteristics. Much like a thaat there is more to modes than just being a set of notes. In early writings of both Plato and Aristotle (approx. 350 BC) there are large sections that describe the effect of different musical modes on mood and on character formation. For example an excerpt from Aristotle’s 'Politics'. 'The musical modes differ essentially from one another, and those who hear them are differently affected by each. Some of them make men sad and grave, like the so called Mixolydian; others enfeeble the mind, like the relaxed modes; another, again, produces a moderate or settled temper, which appears to be the peculiar effect of the Dorian; and the Phrygian inspires enthusiasm'.

For a simplified comparison we will just treat them as group of notes. There are 7 modes and 10 different thaats. Each thaat and mode has 7 notes and if we use our initial correspondence between Hindustani notation and western notations we can see the similarities between the two.

We can see beautiful similarities between the two forms of music. Although there is no thaat which matches the Locrian mode and there are no modes parallel to Todi, Purvi, Marwa and Bhairav thaats. 

Of course this is a very shallow comparison based on the abstract tonal forms. There is a lot more to modes and thaats. Modes are loosely associated with a sentiment or an emotion described by Plato and Aristotle and so are thaats. Thaat system also serves as a framework to classify a raga based on the notes there are in the raga. Ragas are much more nuanced and have lot of other structures rather than just being a set of notes. I must stress that Pandit Bhatkande’s thaat-raga theory is hardly infallible, but it is nevertheless an important classificatory device with which to order, and make sense of, a bewildering array of ragas. Pandit Bhatkhande has shown his ingenuity in using the thaat framework to classify ragas. For instance the behaviors and movements of raga Bhoopali and Deshkar are entirely different despite their sharing a common scale, a striking illustration of the conceptual power of raga. Assigning them to two different thaats points to Pandit Bhatkhande‘s insight into the nature of raga and his genius.

Modes much like thaats play an important part in western form of music as a framework for compositions. A lot of famous compositions are based on different modes. For instance the famous song Another brick in the wall by Pink Floyd is based on Dorian mode, Phrygian mode is used and adopted a lot in Flamenco music.

The beauty of music is immense and transcends geographical, cultural and linguistic boundaries. Even though music has been developed across geographies and cultures and has taken different evolutionary paths but there are lot of uncanny similarities in different forms of music. Discovering those differences and similarities are delightful and inspiring.

There are two ways to pick the svar corresponding to Re (R or r). There are also two ways to pick the svar corresponding to Ga (G or g). Now you can convince yourself that there are 2 x 2 = 4 ways to choose the svars corresponding to the combinations of Re and Ga, i.e., RG, Rg, rG, rg.

By extending this logic we would find that because there are at least 5 svars with two choices each, the total number of combinations we can derive is 2 x 2 x 2 x 2 x 2 = 32.

What Pandit Bhaatkande did was to reduce this exhaustive set of 32 to a more limited set of 10 parent families that in his judgment included the majority of the popular ragas in the Hindustani tradition.

These are the famous 10 thaats of Hindustani classical music and while there is a continuing discussion of the limitations of this scheme, no satisfactory replacement has yet been proposed.

Each thaat represents a parent family in which the included ragas share a family resemblance.

In the circle of thaats above, our starting point = Kalyan Thaat [12 o’clock position with all tivra swaras – RGMDN [the normal variants are being called teevra because their softer versions are komal!] and concluding point = Bhairavi Thaat [its mirror image, 6 o’clock position with all komal swaras – rgmdn].

Moving anti-clockwise from Kalyan, we change tivra swars to komal swaras, in turn, to get the following three thaats before we arrive at Bhairavi thaat where all svars become komal.

Marwa [rGMDN];

Poorvi [rGMdN];

Todi [rgMdN].

Moving clockwise from Kalyan, we change tivra svars to komal svars, in turn, to get the following four thaats (ignore Bhairav thaat for the moment) before we again get to Bhairavi thaat where all svars become komal.

Bilawal [RGmDN];

Khamaj [RGmDn];

Kafi [RgmDn];

Asavari [Rgmdn].

Now note the following:

In the anti-clockwise direction, Ma and Ni remain tivra in all three thaats. The variation comes from transformations in Re, Ga and Dha.

In the clockwise direction, Re remains tivra and Ma remains komal in all four thaats. The variation comes from transformations in Ga, Dha and Ni.

Bhairav thaat [rGmdN] is an outlier in this schema – it does not really fall neatly on either side between Kalyan and Bhairavi thaats.

Eight thaats pair up in four mirror images of each other (the svar that is tivra in one is komal in the other):

Kalyan [RGMDN] and Bhairavi [rgmdn];

Marwa [rGMDN] and Asavari [Rgmdn];

Poorvi [rGMdN] and Kafi [RgmDn];

Todi [rgMdN] and Khamaj [RGmDn].

Bilawal [RGmDn] and Bhairav [rGmDN] are orphans; they are unpaired thaats.

This schema is unsymmetrical and there must be a way to restore symmetry to it. 

We could either add two new thaats, [rgMdn] and [RgMDn], to create pairs for Bilawal and Bhairav and get to 12, a number much more amenable to symmetrical divisions.

Or we could drop the existing Bhairav and create a new thaat [rGMdN].

Shortcomings & Ambiguities of the Thaat System:

Raga Charukeshi [SRGmPdn] cannot be placed unambiguously in any thaat. One has to listen to its movements before assigning it to one family or another. It cannot really accommodate important ragas such as Patdip (S R G M P D N), Ahir bhairav (S R G M P D N) and Madhuvanti (S R G M sharp P D N), and also hard to group ragas with both varieties of either Re, Ga, Ma, Dha and Ni.

Many ragas belonging to different thaats are historically and musically related (e.g. raga Bilaskhani Todi is classified in Bhairavi thaat & raga Miyan ki Todi in Todi thaat). Further, hexatonic and pentatonic ragas cannot be classified in ten thaats since missing notes make the classification ambiguous.

For these and other reasons, many musicians have challenged Bhaatkhande’s thaat system.

Omkarnath Thakur (1897-1967), one of century’s influential music theoreticians and famous khayal singers, rejected the idea of classifying ragas under scale types. But no musicologist so far been able to come up with a raga classification system accepted as widely popular as Bhaatkhande’s.

Ragas with different scales may share a number of characteristic melodic features and motifs & musicians use the term 'ang' (part) for them. Well-known examples are the KanaDha ang (G M R), Malhar ang (M \ R, R / P, N \ P), Bhairav ang (M G \ R — S), and Todi ang (R / G- \ R — S). Bilaval, Kalyan and Sarang angs more difficult to define.

Brief information about these Thaats is explained in the table below:

Sr. No.  Thaat                Description                                                      Related Ragas

 

1      Bilawal     It’s the most fundamental of all the ten Thaats     Deskar, Haunsdhwani, Variations 

                                                                                                           of Bilawal 

 2      Khamaj    It is obtained by replacing the Shuddha Nishad   Rageshree, Jhinjhoti, Des, Tilak

                             of Bilawal by Komal Nishad. Its nature is              Kamod, Jaijaiwanti, Khambavati                                 romantic (Shringar Ras).                                       etc     

 

3      Kafi      Kafi Thaat uses the Komal Gandhar and Komal  Dhanashree, Dhani, Bhimpalasi,                                 Nishad. It’s a late evening raga and is                  Pilu, Megh Malhar, Bageshree                                   associated with the spring.                                    etc.

 

4        Asavari      Asavari Thaat is a blend of Komal Dhaivat and    Asavari, Desi, Darbari, Adana, 

                             Kafi Thaat. It has the nature of renunciation         Jaunpuri etc.

                             and sacrifice as well as suffering. It is apt 

                             for late morning.

 5       Bhairavi      Bhairavi uses all the komal swars, Rishabh,      Malkauns, Bilaskhani Todi,                                         Gandhar, Dhaivat, Nishad. Bhairavi Raga           Bhupali Todi, Kaunsi Kanada etc.

                             is named after the cosmic feminine power 

                            (i.e. Shakti or Maa Durga). It conveys the 

                            feeling of devotion and compassion. It is actually 

                            sung in the early morning, yet customarily its

                            singing ends the program.

6      Bhairav     Bhairav Thaat uses Komal Rishabh and              Ramkali, Gunkari, Meghranjani,

                            It has manly and austere feelings. Komal            Jogiya, Bhairav and its variations                                Dhaivat. It is exceptionally huge and so               etc                                                                                constitutes a large number of note      

                            combinations like Ahir Bhairav, Alam Bhairav, 

                            Anand Bhairav, Bairagi Bhairav, Beehad Bhairav, 

                           Bhavmat Bhairav, Devata Bhairav, Gauri Bhairav, 

                           Nat Bhairav, Shivmat Bhairav etc. It is typically 

                           sung in a devotional mood in the early morning.

 7      Kalyan    This Thaat has a group of evening ragas. As       Yaman, Bhupali, Hindol, Kedar, 

                           this Thaat is considered as a blessing-seeking    Kamod, etc.

                           and soothing. It is sung at the beginning of a 

                           concert in the evening. Like Bhairav, this Thaat 

                           too is vast and so has many variations like 

                           Shuddha Kalyan, Shyam Kalyan, Yaman Kalyan, 

                           Anandi Kalyan, Khem Kalyan (Haunsdhwani +

                           Yaman), Savani Kalyan etc.

 

8  Marwa    It’s a combination of komal Rishabh and              Marwa, Puriya, Bhatiyaar, Bibhas,

                           Kalyan Thaat. This Thaat coveys the mood         Sohoni etc.

                           of the sunset and so has a feeling of 

                           nervousness.

 

                

 9     Poorvi    This is the mixture of komal Dhaivat to                Puriya Dhanashree, Gauri, Shree,

                           Marwa Thaat. It is intensely sober and                Paraj, Basant etc.  

                           is sung at the sunset.

 10  Todi   This is regarded as the king of all Thaats,            Miyan Ki Todi, Gujari Todi,                                          is sung  in the late morning.                                 Madhuvanti

                            

The term thaat is also used to refer to the frets of stringed instruments like the sitar and the veena. It is also used to denote the posture adopted by a Kathak dancer at the beginning of his or her performance.

The modern thaat system was created by Vishnu Narayan Bhatkhande (1860–1936), an influential musicologist in the field of classical music in the early decades of the twentieth century. Bhatkhande modelled his system after the Carnatic melakarta classification, devised around 1640 by the musicologist Venkatamakhin. Bhatkhande visited many of the gharanas (schools) of classical music, conducting a detailed analysis of ragas. His research led him to a system of thirty-two thaats, each named after a prominent raga associated with it. Out of those thirty-two thaats, more than a dozen thaats were popular during his time; however, he chose to highlight only ten such thaats.

According to Bhatkhande, each one of the several traditional ragas is based on, or is a variation of, ten basic thaats, or musical scales or frameworks. The ten thaats are Bilawal, Kalyan, Khamaj, Bhairav, Poorvi, Marwa, Kafi, Asavari, Bhairavi and Todi; if one were to pick a raga at random, in theory it should be possible to classify it into one of these thaats. For instance, the ragas Shree and Puriya Dhanashree are based on the Poorvi thaats, Malkauns on the Bhairavi thaat, and Darbari Kanada on the Asavari thaat.

In Indian classical music, musical notes are called swaras. The seven basic swaras of the scale are named shadja, rishabh, gandhar, madhyam, pancham, dhaivat and nishad, and are abbreviated to Sa, Ri (Carnatic) or Re (Hindustani), Ga, Ma, Pa, Dha, and Ni and written S, R, G, M, P, D, N. Collectively these notes are known as the sargam (the word is an acronym of the consonants of the first four swaras). Sargam is the Indian equivalent to solfège, a technique for the teaching of sight-singing. The tone Sa is not associated with any particular pitch. As in Western moveable solfege, Sa refers to the tonic of a piece or scale rather than to any particular pitch.

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 music, Dheerasankarabharanam in Carnatic). The flattening or sharpening of pitches always occurs with reference to the interval pattern in Bilawal thaat. Each thaat contains a different combination of altered (vikrt) and natural (shuddha) notes with respect to the Bilawal thaat. In any seven-tone scale (starting with S), R, G, D, and N can be natural (shuddha, lit. 'pure') or flat (komal, lit. 'soft') but never sharp, whereas the M can be natural or sharp (tivra, lit. 'fast') but never flat, making twelve notes as in the Western chromatic scale. The sharp or flat tones are called vikrt swara (vikrt, lit. 'altered'). Selecting seven tones in ascending order, where S and P are always natural whereas five other tones (R, G, M, D, N) can assume only one of its two possible forms, results in 32 possible modes which are known as thaats. Out of these thirty-two possibilities, Bhatkhande chose to highlight only ten thaats prominent in his days.

In effect only heptatonic scales are called thaats. Bhatkhande 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 (but see note 5). The relatively small number of thaats reflects Bhatkhande's compromise between accuracy and efficiency: the degree of fit between a raga and its thaat is balanced with the desire to keep the number of basic thaats small. Ambiguities inevitably arise. For example, Raga Hindol, assigned to Kalyan thaat, uses the notes S G M D N, which are also found in Marwa thaat. Jaijaiwanti contains both shuddha Ni and komal Ni (and sometimes both versions of Ga as well), which by definition corresponds to no thaat. Bhatkande resolved such cases 'by an ad hoc consideration, appealing to musical performance practice' (see Ramesh Gangolli's article, cited in note 4 above).

Note that thaats only give a rough structure of the raga and do not give an idea of how the raga should be sung. It is pakad of the raga that gives the chalan or way of singing of the raga.

Bhatkhande named his thaats after the prominent ragas associated with those thaats. Ragas on which the thaats are named are called Janak raga of that thaat. For example, Bilaval Thaat is named after the raga Alhaiya Bilaval. Alhaiya Bilaval raga is therefore Janak raga of Bilaval thaat. Ragas other than the Janak raga of a thaat are called Janya raga.

Many thaats correspond to one or other of the European church modes. The thaats are listed here according to their pitches. Lower pitches (komal or flat) are represented with lowercase letters and natural pitches (shuddha or natural) with uppercase letters. A raised pitch (tivra or sharp) is represented by a letter followed by a single quote (i.e. M'). The upper octave is italicized.

There are many ragas that don't fall in Thaat system. Some ragas have been derived from Carnatic Music and hence do not fall under Hindustani Classical Thaat System. Some of them are:

1. Kirvani 2. Nat Bhairav 3. Charukeshi 4. Madhuvanti 5. Ahir Bhairav

Ragas are normally ascribed to certain periods of the day and night. Narada's Sangita-Makaranda, written sometime between 7th and 11th century, gives warnings to musicians against playing ragas at the incorrect time of day. Traditionally, disastrous consequences are to be expected.Bhatkhande claimed that the correct time to play a raga had a relation to its thaat (and to its vadi).

However, the author of Nai Vaigyanik Paddhati says that the time of a Raga has no importance, especially during meditation by music or during learning or teaching as practiced by the music scholars. Also, it is clear in Bhatkhande Sangeet Shastra at various places that the time do not have any importance while reciting a raga.