Chiang ran into stiff opposition from his officers, including the powerful Chief of Staff of the Military Affairs Commission He Yingqin, the Deputy Chief of Staff Bai Chongxi, the head of the Fifth War Zone Li Zongren, and his German advisor Alexander von Falkenhausen. They argued that the Chinese Army needed more time to recover from its losses at Shanghai, and pointed out that Nanking was highly indefensible topographically. The mostly gently sloping terrain in front of Nanking would make it easy for the attackers to advance on the city, while the Yangtze River behind Nanking would cut off the defenders' retreat.