Khamaj is Bilawal with its Ni lowered to komal: Sa Re Ga Ma Pa Dha komal-Ni. That one softened swara turns the scale from plain to tender, and Khamaj's raags are among the most romantic in Hindustani music: the raags of the night, of thumri and dadra, of the songs a bansuri plays when it plays to charm.
Its swaras
Listen to komal Ni. Shuddh Ni pulls up hard into Sa; komal Ni, a semitone lower, doesn't. It hangs back, turns down towards Dha, and lets the melody linger. Many Khamaj raags use both Nis: shuddh going up to Sa, komal coming down, so that the raag climbs with purpose and descends with longing. Raag Khamaj itself does exactly this.
All ten alankars in Khamaj, to hear in your Sa →
How bright it is
One komal swara: a step below Bilawal on the ladder, beside Purvi.
On the circle of thaats
Khamaj sits between Bilawal and Kafi: raise its Ni and it is Bilawal; lower its Ga as well and it is Kafi.
Its raags
Khamaj's family is the heart of light classical music: Khamaj and Desh, Tilang and Jhinjhoti, Tilak Kamod, Rageshree, Kalavati and Gara, and Jaijaivanti, a grave and beautiful raag of the night that touches komal Ga. Most are raags of the second prahar of the night, and many are sung as thumri.
In the West and the South
In Western music it is the Mixolydian mode: a major scale with its seventh lowered, heard in folk songs and the blues.
In Karnatic music it is the 28th melakarta, Harikambhoji.
Practise it
Practise both Nis side by side, so your fingers and ears know them apart: shuddh Ni rising to Sa, komal Ni falling to Dha.
To make the ten thaats a daily riyaz, Meend has them ready: begin a riyaz of the thaats.
Questions
Which swara is komal in Khamaj thaat?
Ni. Every other swara is shuddh.
Which raags are in Khamaj thaat?
Khamaj, Desh, Tilang, Jhinjhoti, Tilak Kamod, Rageshree, Kalavati, Gara and Jaijaivanti, among others.
Why do Khamaj raags use both Nis?
Shuddh Ni leads strongly up to Sa, komal Ni falls gently to Dha: many Khamaj raags use shuddh Ni going up and komal Ni coming down.