Attempting to defeat the Communists, the KMT armies adopted a policy of encirclement and annihilation; outnumbered, Mao responded with guerrilla tactics influenced by the works of ancient military strategists like Sun Tzu, but Zhou and the new leadership replaced this approach with a policy of open confrontation and conventional warfare. In doing so the Red Army successfully defeated the first and second encirclements.[123][124] Angered at his armies' failure, Chiang Kai-shek personally arrived to lead the operation; also facing setbacks, he retreated to deal with the further Japanese incursions into China.[121][125] As a result of the KMT's change of focus to the defence of China against Japanese expansionism, the Red Army expanded its area of control, eventually encompassing a population of 3 million.[124] Mao proceeded with his land reform program, in November 1931 announcing the start of a "land verification project" which was expanded in June 1933, also orchestrating education programs and implementing measures to increase female political participation.[126] Viewing the Communists as a greater threat than the Japanese, Chiang returned to Jiangxi, initiating the fifth encirclement campaign, involving the construction of a concrete and barbed wire "wall of fire" around the state, accompanied by aerial bombardment, to which Zhou's tactics proved ineffective. Trapped inside, morale among the Red Army dropped as food and medicine became scarce, and the leadership decided to evacuate.[127]