塘沽協定
After that, in an effort to prevent further conflict with Japan, He Yingqin opposed military action against the Japanese, and disarmed Feng Yuxiang's anti-Japanese army. However, when the Blue Shirts Society (BSS), the secret organization of the Whampoa Clique of the KMT, and a firm anti-Japanese group fought back with assassination and other violent activities in 1935, the Japanese argued that it was violation of the Tanggu Truce. Japanese General Yoshijirō Umezu, who was commander of Japanese troops in Northern China at that time provided He with proof of the BSS activities which had been gathered by the Japanese spy-master Kenji Doihara, and He was forced to sign the He-Umezu Agreement which required that all forces having relations with the BSS inclusive of military police, including KMT regular forces such as 2nd Division and 25th Division be evacuated from Beijing and out of Hebei province.