The bansuri is a transverse flute from India, literally from the words bans (bamboo) and suri. It is one of the oldest musical instruments. All half notes, accidentals and microtones are produced by a unique fingering system. The finger holes have to be precisely covered either fully or half by the phalanxes of the fingers and not by the fingertips. This technique also simplifies the playing of longer bansuris. The standard quality of the Indian bansuris produce a quite beautiful sound, but their tuning is often not exactly to the western standard notes. It can happen that they sometimes sound slightly out of tune to the western ear.
The professional Bansuri flutes are made from only one type of bamboo, called cinchor. This bamboo only grows in the interior forests of Assam. Only Bamboo of 3 to 4 years old and of the proper diameter can be used. The cut bamboo is then treated, dried and stored for years until it is properly seasoned. The longer it is seasoned the better the flute. The correct notes are achieved by piercing the seasoned bamboo with hot iron rods in precise positions along the length. There may be some curvature in these flutes, however it will not affect the sound quality.