勤王運動
Vietnam had gradually become a French colony between 1859 and 1883. The first phase started in 1859, when French and Spanish forces began an invasion of southern Vietnam, leading to the ceding of three southern provinces to form the colony of Cochinchina under the Treaty of Saigon in 1864. In 1867, the French seized three further provinces and by 1883, the process was complete, when northern and central Vietnam were conquered and made into the French protectorates of Tonkin and Annam and incorporated into French Indochina. Initially, military resistance to French rule came through the Cần Vương movement led by Tôn Thất Thuyết and Phan Đình Phùng, which sought to install the boy Emperor Hàm Nghi at the head of an independent nation. However, with the death of Phùng in 1895, military opposition effectively ended. The only other notable incidents after this came in 1917 with the Thai Nguyen rebellion. The lack of militant activity changed in the late 1920s with the formation of the VNQDĐ, or Vietnamese Nationalist Party. The party began to generate attention among French colonial authorities and was blamed for the assassination of Bazin on 9 February 1929, a French labour recruiter despised among the populace, leading to a heavy French crackdown. The French purges caused considerable detriment to the independence movement in general and the VNQDĐ in particular. Nearly 1000 VNQDĐ members were arrested; the demolition of many of the Party's facilities ensued. The VNQDĐ decided to abandon its clandestine philosophy and engage in open attacks against the French, hoping to foment a general uprising among the people. A minority felt that even though there was a danger that French crackdowns would irreparably weaken the party, they should try and bide their time and go into hiding in the mountainous Hoa Binh Province and focus on writing propaganda books and pamphlets, and take an extended period to prepare a large armed attack. It has also been alleged that Ho Chi Minh had tried to contact the VNQDD leadership to try and advise them to bide their time.