Thumri is indeed a diversified form of classical music, with the incorporation of the brilliant combinations of bandishes of various ranges, taals and another innovative version of bandish, bol-banav in slow tempo (vilambit laya). Coalesced together, they give an impression of lithe and sprightly fashion to the listener, because they do not pay much attention to grammar. And this bol-banav truly tests the skill and control of a singer during a recital, with the accompaniment of a tabla, that slowly moves to a swifter tempo. Like khayal, a singer has to return to the mukhda after every completion of a course. However, during the culminating phase of frenzy, the singer may increase the tempo by resorting to taans. Benaras, Lucknow and Punjab are the three leading schools of music in thumri, taking this form to sublime heights.

Like khayal, the thumri too has a shtayi and antara. Yet the singers are not bound to the systematic exposition of the two parts in the manner of khayal singers. For the most part, a good number of thumris sung in the 20th century were in lighter raaags like Pilu, Kafi, Jogiya, Bhairavi, Tilang, Des, Khammaj and Pahadi. Such ragas, being extremely adaptable and supple, offer the singer a wider vocal mobility unlike the more serious ragas, which impose the constraints of grammar and development. Being less grammar-bound, lighter ragas are extremely receptive to foreign notes. In fact, they become more catchy and swingy when foreign notes are intermingled into their flexible structure. Thumri singers ingeniously use this to introduce lively and novel emotional and tonal colours into their recital. Thumri bandishes are all set to Deepchandi, Roopak, Keharva, Addha and Punjabi taals. With the exception of Roopak, none of the others are generally used by khayal singers.

A thumri relies on bol-banav, or the expressive and heartrending use of the words of the bandish in slow tempo. Many subtle shades of mood and meaning are conveyed through the enthralling inflections and modulations of words and voice when the singer starts on the bol-banav. Bol-banav most definitely tests a singer`s range of imagination, especially her ability to charge words and phrases with the varying hues of moods, as also her feel for their humidly sensuous potential. As in a khayal, the singer returns to the mukhda after every cycle of improvisation.

After the bol-banav, the singer enters the concluding phase by signalling the percussionist to double or quadruple the tempo of drumming, but the singer herself does not change her speed of singing. The tabla player plays a series of nimble and compact rhythmic improvisations called laggis, which are meant to rouse the audience and give the singer some respite. The singer then picks the sthayi and improvises it for a while longer. He or she may resort to ornaments such taans before concluding at a fast pace.

Benaras, Lucknow and Punjab are the three distinctive styles of thumri to rise to fame in the 20th century. The differences between the Lucknow and Benaras styles are not so apparent to the non-expert. Together, they constitute what is generally known as the Poorab-ang (Eastern) thumri. The Lucknow style is more explicit in expressing erotic and amatory moods, rich in minute details and poetically very dense. Called bandish-ki-thumri, it is considered by many to be structured like a chhota khayal and thus sung as one in khayal recitals. Its heyday was in the 19th century. By the early 20th century, the bol-banav thumri of Benaras overshadowed it to the point that it is virtually never heard today. The legendary Begum Akhtar was possibly one of the last eminent exponents of this style in the 20th century.

The Benaras style resembles the khayal in several respects, especially in its stately elegance and spacious development and is thus considered to be the most `classical` of styles. The Benaras singers are the acknowledged masters and mistresses of bol-banav thumri. Some of the greatest thumri singers of the Poorab-ang are Azam Bai, Badi Moti Bai, Janaki Bai, Siddheshwari Devi, Girija Devi, Shobha Gurtu and Channulal Misra.

The Punjab-ang thumri depicts the influence of the folk music of North-Western Punjab. Founded an popularised by Ustad Bade Ghulam Ali Khan and his brother Barkhat Ali Khan, it is, in comparison to the Poorab schools, a more recent entrant. Feisty, zesty and colourful in the extreme, the Punjab style caught the fancy of people like wildfire in the 1950s. The uniqueness of the approach coupled with Bade Ghulam`s electrifying vocal prowess went to make Punjab-ang one of the most popular of thumri styles. His son Ustad Munnawar Ali Khan too was an exceptional singer of thumri in the Punjab style.

Thumri, once associated with the ambience of luxurious kothas and the leisurely courtesan culture prevalent in several parts of North India, during the 19th century and the first half of the 20th century, is now a respectable art form. The tags of amatory audacity and the unabashed lifestyles of courtesan-singers and dancers naturally made thumri the object of prudish ire. Yet, without a hint of doubt, it was in this courtesan-milieu, that this artistic soiree culture musical form grew and developed to its present stature. Once associated with the debauched decadence of the kothas, and condemned on that account by the fastidious, it is now a popular light form sung at the end of every classical concert by modest and stolid women and men from upright middle class homes. The blatantly and disquietingly erotic thus became the compassionately and tastefully domestic. The question that remains to be asked is whether this form, founded on and fostered by the deep and forceful rhythms of shringar rasa would grow pale and wilt, like some magnificent exotic flower in the puritanical environs of a middle-class living room, in the times to come. As things stand, the breed of singers specializing solely in thumri gayaki is coming down. Alongside, the number of khayal singers adept at singing thumri has gone up. Many of them do so to enlarge their musical repertoire.

Origin and Development of Thumri, Indian Music: The first traces of thumri go back to the 15th century, known to have likenesses with the dance form Kathak. Thumri is a lively musical style, evoking a sense of sensuality and amorousness, aimed at the subtle feelings of the heart. However, historical records speak of a different version of thumri during the 19th century, bearing similarity with khayal and depending on the elaboration of ragas.