The Cambodian rebellion of 1820, also known as the Neak sel Rebellion (lit. "the holy man's rebellion"), was a Cambodian revolt against Vietnam led by a monk named Kai.
At the time, Cambodia was in the grip of a "Dark Age", with internal affairs subject to interference from Siam and Vietnam. In 1813, Siam intervened in a royal dispute in Cambodia, prompting the Cambodian King Ang Chan to seek assistance from Vietnam. Vietnam subsequently stationed troops in Cambodia, transforming it into a protectorate. To strengthen its control over Cambodia, Vietnam constructed three major roads within the country to facilitate military transport. In 1817, it seized the important port of Châu ÃÂá»Âc, and two years later, it dug the Vénh Tế Canal between the port and HàTiên, annexing Cambodian territory south of the canal.
In 1819, Khmer and Vietnamese labors were forced to reconstruct the Vénh Tế Canal. Kai, a monk originally from Wat Sambaur who claimed supernatural powers, revolted against the Vietnamese.
Kai occupied the Khmer holy site Ba Phnom and subsequently declared king. Most of his followers were recruited in the area around Tây Ninh. Many Buddhist monks joined his forces. The rebels marched toward Phnom Penh, and three Cambodian generals, Chaophraya Tei (or Somdet Tei, Samdech Tei), Narin Kol and Naike, joined them.
King Ang Chan wanted to flee the capital and sent a letter to Saigon to ask for help. Lê VÃÂn Duyá»Ât, the viceroy of Cochinchina, ordered Nguyá» n VÃÂn Thoại and Nguyá» n VÃÂn Tràto assemble an expeditionary force. The Vietnamese army defeated the rebels, killed many of them. Kai escaped, but was pursued and killed with many monks in Kampong Cham.Kai's assistance, the novice Kuy, escaped to live among the Lao. Other leaders had to surrender, including Chaophraya Tei, Narin Kol and Naike. They were put to death in Phnom Penh and Saigon.
This rebellion served as a pretext for Vietnam to re-establish its military presence in Cambodia, since the following year, Vietnam sent Thoại Ngá»Âc Hầu again to "protect" the country.