Peng was one of the most senior generals who defended the Jiangxi Soviet from Chiang's attempts to capture it, and his successes were rivaled only by Lin Biao. Peng participated in the Long March, and supported Mao Zedong at the Zunyi Conference, which was critical to Mao's rise to power. During the 1937–1945 Second Sino-Japanese War, Peng was one of the strongest supporters of pursuing a ceasefire with the Kuomintang in order to concentrate China's collective resources on resisting the Japanese Empire. Peng was the senior commander in the combined Kuomintang-Communist efforts to resist the Japanese occupation of Shanxi in 1937; and, by 1938, was in command of 2/3 of the Eighth Route Army. In 1940, Peng conducted the Hundred Regiments Offensive, a massive Communist effort to disrupt Japanese logistical networks across northern China. The Hundred Regiments Offensive was modestly successful, but political disputes within the Communist Party led to Peng being recalled to Yan'an, and he spent the rest of the war without an active command. After the Japanese surrendered, in 1945, Peng was given command of Communist forces in Northwest China. He was the most senior commander responsible for defending the Communist leadership in Shaanxi from Kuomintang forces, saving Mao from being captured at least once. Peng eventually defeated the Kuomintang in Northwest China, captured huge amounts of military supplies, and actively incorporated the huge area, including Xinjiang, into the People's Republic of China.