Operation Bison is the codename of the assault and capture of Zoji La, Dras and Kargil district in Ladakh by the Indian Army during the Indo-Pakistani War of 1947-1948. Zoji La had been seized by Pakistani raiders in 1948 in their campaign to capture Ladakh. The pass was recaptured by Indian forces on 1 November in a daring assault, which achieved success primarily due to the surprise use of armour, then the highest altitude at which armour had operated in combat in the world.