In 1933, the Japanese attacked the Great Wall region, the Tanggu Truce taking place in its aftermath, giving Japan control of Rehe province as well as a demilitarized zone between the Great Wall and Beiping-Tianjin region. Here the Japanese aim was to create another buffer region, this time between Manchukuo and the Chinese Nationalist government in Nanking.

Japan increasingly used internal conflict in China to reduce the strength of her fractious opponents. This was precipitated by the fact that even years after the Northern Expedition, the political power of the Nationalist government was limited to just the area of the Yangtze River Delta. Other sections of China were essentially in the hands of local Chinese warlords. Japan sought various Chinese collaborators and helped them establish governments friendly to Japan. This policy was called the Specialization of North China (Chinese: ?????; pinyin: h?ab?it?sh?h?a), more commonly known as the North China Autonomous Movement. The northern provinces affected by this policy were Chahar, Suiyuan, Hebei, Shanxi, and Shandong.

This Japanese policy was most effective in the area of what is now Inner Mongolia and Hebei. In 1935, under Japanese pressure, China signed the He-Umezu Agreement, which forbad the KMT from conducting party operations in Hebei. In the same year, the Ching-Doihara Agreement was signed expelling the KMT from Chahar. Thus, by the end of 1935 the Chinese government had essentially abandoned northern China. In its place, the Japanese-backed East Hebei Autonomous Council and the Hebei-Chahar Political Council were established. There in the empty space of Chahar the Mongol Military Government (?????) was formed on May 12, 1936, Japan providing all necessary military and economic aid. Afterwards Chinese volunteer forces continued to resist Japanese aggression in Manchuria, and Chahar and Suiyuan.

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