According to the references found in the Vedas, Puranas, and various religious scriptures, the form of Bhagavati Chhinnamasta is extremely secretive. Only a qualified Sadhaka can understand Her mysteries. Among the Dasha Mahavidya, Goddess Chhinnamasta holds the sixth position.
The story of the manifestation of Goddess Chhinnamasta is as follows: Once, Goddess Bhagavati went to bathe in the Mandakini River along with Her companions Jaya and Vijaya. After bathing, due to Kshudhagni, i.e., the fire of hunger, Goddess Bhagavati became dark-complexioned. At that time, Her companions also requested Her to provide them with some food. The Goddess asked them to wait for some time. Thereafter, when the companions again requested food after waiting for some time, the Goddess asked them to wait a little longer.
Upon this, both the companions humbly said to the Goddess - 'O Devi! A mother provides food to her children immediately when they feel hunger. Why are You neglecting us?'
Hearing the sweet words of Her companions, in order to satisfy their hunger, the compassionate Goddess struck Her own head with Her sword and severed it. The severed head fell into the left hand of the Goddess, and from Her Kabandha, i.e., torso, three streams of blood began to flow. Out of these, the Goddess directed two streams towards Her companions. Jaya and Vijaya joyfully drank the streams of blood flowing from the Goddess's torso and became pleased, while the Goddess Herself drank the third stream.
From that very moment, the Goddess became famous throughout the world as Chhinnamasta.
According to another legend, in ancient times there was a king named Damodara who ruled his kingdom justly and took care of and protected his subjects. The name of the queen was Rupama. From their names, this place came to be known as Rajarupama, which later became famous as Rajrappa.
According to one story, once on the night of Purnima, King Damodara went in search of hunting and reached the confluence of the Bhairavi River. While sleeping at night, the king saw in his dream a divine Kanya, i.e., maiden wearing red garments and possessing a radiant face.
That maiden said to the king - 'O King! At this age, due to the absence of a child, your life appears empty. If you follow my command, the queen's womb will surely be blessed.' Saying this, the maiden disappeared.
As soon as the king awoke, he began wandering here and there. At that very moment, his eyes fell upon the same maiden seen in the dream. That maiden appeared before the king from within the water. Her form was extremely beautiful and divine. Seeing the maiden emerging from the water, the king became frightened.
Seeing the king frightened, the maiden said - 'O King! I am Goddess Chhinnamasta. The people of Kali Yuga are not capable of knowing My true form. I have been residing secretly in this forest since ancient times. I grant you the boon that exactly in the ninth month from today, you will be blessed with a son. O King! Near the confluence of the Bhairavi-Bheda and Damodara River, you will see a temple of Mine. Inside this temple, an image of Mine is engraved on a rock. You should worship Me in the morning.'
Saying this, Mother Chhinnamasta disappeared. From that time onwards, this sacred place became popular as the Rajrappa Tirtha.