The Fall
Arjuna had agreed, reluctantly, to shoot Bhishma — the grandfather, the teacher, the man who had protected the Kuru dynasty for three generations. Using Shikhandi as a shield (Bhishma had vowed not to shoot at Shikhandi), Arjuna unleashed his arrows.
Bhishma fell. His body was pierced by so many arrows that when he touched the ground, he rested on a bed of arrows rather than the earth itself.
He was alive. He had the boon of *iccha-mrityu* — death at will. And it was not Uttarayana yet.
The Bed
The armies paused. Both sides came to honor him — including Duryodhana, whom he had fought for, and Yudhishthira, whom he had fought against.
Bhishma lay on his arrow-bed for 58 days while the war ended around him.
A king brought a soft pillow for his head. Bhishma refused. He asked Karna — his great enemy in life — to come. They were reconciled.
He asked for water. Someone brought cold water in a golden cup. Bhishma refused — a warrior on a battlefield does not drink from gold. Arjuna shot an arrow into the earth and pure water sprang up into Bhishma's mouth.
The Teaching
For 58 days, Bhishma taught. He taught Yudhishthira everything: statecraft, dharma, the duties of kings, the nature of time, the proper conduct of war, the duties to the dead, the nature of liberation.
The Anushasana Parva of the Mahabharata is entirely this teaching.
On the morning of Uttarayana, when the sun turned north, Bhishma closed his eyes and left his body.