Before the assembled armies engaged in the fight, they settled their rules regarding different kinds of combat, with a view to fairness. If a combatant, after fighting, withdrew, he was to be allowed to do so. Those who engaged in a battle of words, were to be engaged with words only a car-Warrior was to fight a car-Warrior; an elephant rider an elephant rider; a horseman a horseman; and a foot soldier a foot soldier a warrior was to fight another after consideration of fitness, willingness, bravery and strength, and after having duly challenged him. One seeking refuge, retreating, or whose weapons were broken, or who was not clad in armour, was never to be struck; while charioteers, animals, and men engaged in carrying weapons, or those who played on drums or blew the conch, were never to be attacked.
Sanjaya and Dhritarashtra: As Dhritarashtra was unable to witness the combat, and refused the gift of sight offered to him for he did not desire to see the slaughter of friends and relations Vyasa granted a boon to Sanjaya, enabling him to witness the whole scene of battle, and to describe it in detail to the blind old king.
The Battle Arrays: Yudhisthira bade Arjuna to arrange his troops for the day, and that hero made an immovable Vyuha (array) called Vajra (Lightning), and Bhima was placed at the head of the fight. The Kuru army appeared like the full, rolling and surging Ganga. The armies of Dhritarashtra stood facing west, while those of the Pandavas faced the east; and Bhishma, who led the Kurus, arrayed his troops in human, celestial, Gandharva, and Asura Vyuhas, as occasion required.