In the past, the dan day was an accompanying instrument used only for one genre of songs, which later divided in two variants known today as hat cua dinh and hat a dao.
The dan day, exclusively played by men, most probably came into being in the 15th century when musical genres were forming.
This bass instrument has high frets and a very long neck. Thanks to the unusual technique called ngon chun (slacking the string with the fingers), players may lower the tones. The low register and the dull, warm but short sounds of the dan day always distinguish it from other instruments in a concert.
Apart from accompanying hat cua dinh and hat a dao songs, the dan day is now used to accompany poems as well. Due to its refined and modest sounds, the dan day is sometimes compared to a secluded philosopher.