The East Hopei Army was a military force formed from the Peace Preservation Corps founded by the Tangku Treaty of 1933 in northern China. When Yin Ju-keng proclaimed independence for the East Hebei Autonomous Council, he reformed the peace corps into a new army to use as the council's military. The Japanese recognized this, and provided full support, since the council was essentially their puppet state.
When the council was merged with the Provisional Government of the Republic of China in 1938, the East Hopei Army became the nucleus of the new "provisional army", which itself was merged with the Chinese National Army of the Reorganized National Government.
The men of the army were trained and drilled with propaganda by Japanese officers and advisors from the Kwangtung Army.
The East Hopei Army had 4 Corps divided into 3 Brigades each and a Training Corps. Each brigade (called "divisions") was divided into 3 sub-brigades, each sub-brigade had an attached Japanese Advisor. Strength and organization July, 1937:
- East Hopei Army - Yin Ju-keng
- 1st Corps "Tungchow" - Chang Ching-yu; 4,000 men
- 2nd Corps "Tsunhua" - Chang Yen-tien; 4,000 men
- 3rd Corps "Tungchow" - Li Yen-sheng; 4,000 men
- 4th Corps "Tsunhua" - Han Tze-hsi; 4,000 men
- Training Corps "Tungchow" - Yin Ju-keng; 2,000 men
The basis of the army's organization was later used by the provisional army of the provisional government.
December 1935, 4th Detachment of the East Hopei Army attacked the Nationalist held towns of Taku and the port of Tangku. Forces from the 32nd Army killed two of the East Hopei soldiers and the rest retreated. Threats were made by the Japanese and the 32nd Army was withdrawn. The East Hopei Army then occupied the two towns.
July 1937 they were involved in the Marco Polo Bridge Incident and Battle of Beiping-Tianjin until they revolted in the Tungchow Mutiny on the morning of 29 July 1937. After the mutiny was put down by the Japanese the East Hopei Army was dissolved as was the Autonomous Government.