Bilaval or Bilawal (IAST: Bilāval) is the most basic of all the ten thaats of Hindustani classical music of the Indian subcontinent.
[1] All the swaras in the thaat are shuddha or all swaras in the natural scale.
Bilaval as a raga is not rendered these days however a small variation of the raga called Alhaiya Bilaval is very common.
This is a morning raga and its pictorial descriptions create a rich, sensuous ambience in consonance with its performance.
Ragas in Bilaval include: