Taan (Hindi: तान, Urdu: تان) is a technique used in the vocal performance of a raga in Hindustani classical music.
It involves the improvisation of very rapid melodic passages using vowels, often the long "a" as in the word "far", and it targets at improvising and to expand weaving together the notes in a fast tempo.
[1] The murki, a type of ornamentation, is a swift, short and taan-like movement that is heavily used in thumri.
This is a difficult type of a taan as in this correct pronunciation, meaning of the composition, everything has to be taken into consideration.
Koot Taan : The notes do not remain in order.