Manekshaw was appointed an army commander on 5 December, taking command of Western Command as GOC-in-C. In 1964, he moved from Shimla to Calcutta as the GOC-in-C Eastern Command, having received his appointment on 16 November. There he responded to an insurgency in Nagaland, for which he was awarded the Padma Bhushan in 1968. Chief of Army Staff Gen. P. P. Kumaramangalam, retired as chief of army staff (COAS) in June 1969. Though Manekshaw was the most senior army commander, Defence Minister Sardar Swaran Singh favoured Lt. Gen. Harbaksh Singh, who had played a key role as the GOC-in-C of Western Command during the Indo-Pakistani War of 1965. Despite this, Manekshaw was appointed as the eighth chief of the army staff on 8 June 1969. During his tenure, he developed the Indian Army into an efficient instrument of war, and was instrumental in stopping a plan to reserve positions in the army for Scheduled Castes and Scheduled Tribes. Though he was Parsi, a minority group in India, Manekshaw felt that the practice would compromise the ethos of the army and believed that all must be given an equal chance. In the capacity of COAS, Manekshaw once visited a battalion of 8 Gorkha Rifles in July 1969. He asked an orderly if he knew the name of his chief. The orderly replied that he did, and on being asked to name the chief, he said "Sam Bahadur". This eventually became Manekshaw's nickname. Indo-Pakistani War of 1971 The Indo-Pakistani War of 1971 was sparked by the Bangladesh Liberation war, a conflict between the traditionally dominant West Pakistanis and the majority East Pakistanis. In 1970, East Pakistanis demanded autonomy for the state, but the Pakistani government failed to satisfy these demands and, in early 1971, a demand for secession took root in East Pakistan. In March, the Pakistan Armed Forces launched a fierce campaign to curb the secessionists, the latter including soldiers and police from East Pakistan. Thousands of East Pakistanis died, and nearly ten million refugees fled to West Bengal, an adjacent Indian state. In April, India decided to assist in the formation of the new nation of Bangladesh. During a cabinet meeting towards the end of April, Prime Minister Indira Gandhi asked Manekshaw if he was prepared to go to war with Pakistan. He replied that most of his armoured and infantry divisions were deployed elsewhere, only twelve of his tanks