Bhagwan Parashurama was the sixth incarnation of Lord Vishnu and his birth anniversary is celebrated as Parshurama Jayanti. It comes on Tritiya (third day) of the Shukla paksha.  Lord Parasuram was son of Sage Jamadagni and Renuka and was born during the waxing phase of moon in the month of Vaisakha.  Lord Parshuram was the fifth son .The ious works of Lord Parashurama are present in Mahabharat, Ramayana and the Puranas. Lord Parashurama killed 21 generations of Kshattriyas who were the ruling class to protect the innocent people. .  
Bhagwan Parashurama  grew up in to be a powerful youth. Even though he was a Brahmin by birth, he expressed lot of interest in weapons and archery .After completing his studies under his father who was himself a powerful archer, Lord Parshuram went to the Gandhamadana mountains. Over there, he undertook severe penances to please Lord Shiva.

Lord Shiva was pleased with this, and appeared before him and told  him that he would grant a boon. Parashurama expressed his desire to obtain celestial weapons from the God. Lord Shiva told him that he would grant the boon only when Parashurama proved himself to be a worthy one. So, After years of penances, Lord Shiva was pleased with Parashurama’s devotion and summoned him. Lord Shiva ordered to Parashurama to slay the Daityas and Danavas who were the enemies of the Devas, to which the latter agreed.

After vanquishing the Daityas and Danavas in battle, Parashurama proved himself worthy and acquired the celestial weapons from Lord Shiva.

 Once the sage Jamadagni was angry on his wife Renuka as she went to Royal place of king KarthavirArjun  to teach him a lesson not to burn and disturb the ashram, but unfortunately it became late and was early morning when she returned  to the ashram.

The Rishi called his eldest son, handed him an axe and asked the boys to kill his mother. Horrified, the first four sons refused and so Jamadagni turned them to stone.. Finally only his youngest son, Parashurama was left. Ever obedient, the boy beheaded his mother with that axe.

Being so pleased Rishi Jamadagni, offered two boons to his fifth son Lord Parashurama.  Lord Parshuram asked that his mother be brought back to life and his four brothers to be returned to life.  Impressed by the affection and devotion of his son, Jamadagni granted all his requests. Thus, he was named as Parshu Ram due to his axe from the father.

Once Kartgavir Arjun with his groups went to Jamdagni Rishi Ashram  to take some rest. Rishi welcomed the kind with his Yogic powers KarthavirArjun  asked the secret behind. Muni Jamdagni told that it is because of his Yogic powers and Kaamdhenu Gau mata. 

Kashtyriya vir Arjuna ordered Muni to hand over this cow, which Muni had turned down his request.   At this, the king enraged and attacked and finally destroyed the whole Ashram. He had killed KarthaviirArjun who had thousands of arms powers. He had a boon by Lord Dattatreya that no one would be able to kill him except Lord Dattatraya. Lord Parshuram was Lord Vishnu avtar himself. Fight between two continued and finally Lord Parshuram killed the Kahstriyavir Arjuna in the war with his axe. Parashurama destroyed the cruel Kashtiryas 21 times from earth as he had seen 21 cut on his father body.  

This day, (Parashuram jayanti) is celebrated with pujas bhajans Etc. Also people wear new clothes.  Fasts are kept one night before this day and continued until the next day. These fasts are mainly followed by women. They pray for happy and prosperous lives of their families. Lord Vishnu and Parashuram are worshipped on this day. Chanting of Vishnu is done, all night long without sleeping by the worshippers. People sing and dance all overnight to celebrate the Jayanti. People also donate food to Brahmins.