The fight between Parashurama, an incarnation of Vishnu, and
Bhishma, the grandsire of Kauravas and Pandavas, is the battle of the equals. It
was the battle between Guru and Shishya. Parashurama fought for getting justice
for Amba, the eldest daughter of King of Kashi. Bhishma fought for defending
the valor of Kshatriyas.
Amba, Ambika and Ambalika were daughters of King of Kashi.
When the Swayamvara ceremony of the princesses was being held, Bhishma arrived
there and defeated all the suitors and won the three maidens. Bhishma won the
maidens through Virya Shulka – a suitor who shows most valor wins the hand of
maiden.
Bhishma performed this deed for Vichitravirya, the king of
Hastinapura.
Just before the marriage ceremony, Amba informed Bhishma
that she had already chosen the king of Shalva as her groom. So it would not be
dharma for her to marry Vichitravirya as she has given her mind to another man.
Bhishma then allowed the eldest maiden to go to king of
Shalva. But king of Shalva who was defeated by Bhishma in the Swayamvara
ceremony did not accept Amba.
Amba then took shelter in an ashram. Here she met
Parashurama, who along with other saints felt that Bhishma was responsible for
the plight of Amba.
Parashurama challenged Bhishma in the Kurukshetra to get
justice to Amba. After taking the blessing of Parashurama, Bhishma mounted on his
chariot. This act earned him the blessing of his preceptor.
They used all sort of weapons. Both were injured in the
battle. Finally both of them used the Brahmastra. It created havoc in the sky.
The heat of it was unbearable.
Then Sage Narada descended on earth and asked both Bhishma
and Parashurama to stop the fighting.
Sage Narada reminded Parashurama that it was dharma of
Kshatriya like Bhishma to fight and it is not possible to defeat a warrior who
follows Dharma.
Bhishma also was reminded about the greatness of Parashurama
and the reality that Parashurama can never be defeated.
Thus they both withdrew from the battlefield.