Sun recovered, and in 1942 he and his 38th Division gained fame during the Allied retreat in Burma by rescuing a nearly surrounded British division at Yenangyaung. For this action, London awarded Sun the Commander Order of the British Empire. While other units collapsed before the Japanese onslaught, Sun kept his division together, withdrawing in good order through mountainous northwest Burma and joining Lieutenant General Joseph Stilwell's training operation at Ramgarh as deputy commander of the Chinese army in India—the so-called X-Force.
In late 1943, Sun led his New First Army into northern Burma to help clear the Ledo Road route. In December, Sun took Yupbang Ga, initiating a six-month drive through the Hukawng and Mugaung valleys, toward Myitkina. Sun had impressed Stilwell earlier as aggressive and professional. But in January 1944, "Vinegar Joe" fulminated at apparent Chinese malingering, convinced that Jiang Jieshi (Chiang Kai-shek) had ordered Sun not to risk well-trained Chinese forces in Burma's jungles. Sun countered that American intelligence grossly underestimated Japanese strength, necessitating slowing for more reconnaissance. Scholars substantiate both allegations. Still, in March the 38th fought successfully alongside Merrill's Marauders in the first joint Sino-American combat operation. Sun took Kamaing, just west of Myitkina, in June and Bhamo, near the Chinese border, in December. Sun's 38th Division led the X-Force across the frontier, linking up with the Yunnan Province–based Y-Force on 27 January 1945. This action ended the three-year blockade of China and opened the way for the newly christened Stilwell Road to Kunming. In August, Sun took the Japanese surrender in Guangzhou (Canton), Guangdong (Kwangtung) Province.
After combat in the Chinese Civil War, Sun became commander in chief of all Nationalist forces in Taiwan in 1950. In 1955, however, he was forced to resign following a subordinate's alleged anti-Jiang plot. Although a secret investigation cleared him of any wrongdoing, he was not only forced from his position but was placed under house arrest from 1955 until 1988, after the end of the Jiang era. A tragic and popular figure, Sun died at his home in Taichung, Taiwan, on 19 November 1990.
Allen, Louis. Burma: The Longest War, 1941–1945. New York: St. Martin's Press, 1984.; Dorn, Frank. Walkout with Stilwell in Burma. New York: Thomas Y. Crowell, 1971.; Romanus, Charles F., and Riley Sunderland. U.S. Army in World War II: The China-Burma-India Theater. 3 vols. Washington, DC: Office of the Chief of Military History, Department of the Army, 1953–1959.; Tuchman, Barbara. Stilwell and the American Experience in China, 1911–1945. New York: Macmillan, 1970.