science also at NDU. One of his professors at NDU was general Jehangir Karamat who served as Musharraf's guidance counsellor and instructor who had significant influence on Musharraf's philosophy and critical thinking. He did not play any significant role in Pakistan's proxy war in the 1979–1989 Soviet invasion of Afghanistan. In 1987, he became a brigade commander of a new brigade of the SSG near Siachen Glacier. He was personally chosen by then-President and Chief of Army Staff general Zia-ul-Haq for this assignment due to Musharraf's wide experience in mountain and arctic warfare. In September 1987, Musharraf commanded an assault at Bilafond La before being pushed back. He studied at the Royal College of Defence Studies (RCDS) in Britain during 1990–91. His course-mates included Major-generals B. S. Malik and Ashok Mehta of the Indian Army, and Ali Kuli Khan of Pakistan Army. In his course studies, Musharraf performed extremely in relation to his classmates, submitted his master's degree thesis, titled "Impact of Arm Race in the Indo-Pakistan subcontinent", and earned good remarks. He submitted his thesis to Commandant General Antony Walker who regarded Musharraf as one of his finest students he had seen in his entire career. At one point, Walker described Musharraf: "A capable, articulate and extremely personable officer, who made a valuable impact at RCDS. His country is fortunate to have the services of a man of his undeniable quality." He graduated with a master's degree from RCDS and returned to Pakistan soon after. Upon returning in the 1980s, Musharraf took an interest in the emerging Pakistani rock music genre, and often listened to rock music after leaving duty. During that decade, regarded as the time when rock music in Pakistan began, Musharraf was reportedly keen on the popular Western fashions of the time, which were then very popular in government and public circles. Whilst in the Army he earned the nickname "Cowboy" for his westernised ways and his fashion interest in Western clothing. Higher commands (1991–1995) Earlier in 1988–89, as Brigadier, Musharraf proposed the Kargil infiltration to Prime Minister Benazir Bhutto but she rebuffed the plan. In 1991–93, he secured a two-star promotion, elevating him to the rank of major general and held the command of 40th Division as its GOC, stationed in Okara Military District in Punjab Province. In 1993–95, Major-General Musharraf worked closely with the Chief of Army Staff as Director-General of Pakistan Army's Directorate