Why did Krishna attack Bhishma?

Bhishma is the most long-standing character in the Mahabharata. He is the eighth son of Ganga, the divine river goddess, and Shantanu the king of Hastinapur.

Bhishma’s original name is Devavrata. During his sixteenth year, he takes a lifelong oath of celibacy in order to ensure that his father can wed the fisher princess, Satyavati.

In the Kurukshetra war, Bhishma fights on the side of the Kauravas against the Pandavas. He falls on the tenth day to a deceptive tactic employed by Krishna, t...