Jakar tshechu, Guru Rinpoche thongdrel with the Guru, his two wives and eight manifestations

A tshechu (or tsechu) is an annual religious Bhutanese festival held in each district or dzongkhag of Bhutan on the tenth day of a month of the lunar Tibetan calendar. Tsechus are religious festivals, but also large social gatherings, which perform the function of social bonding among people of remote and spread-out villages. Large markets also congregate at the fair locations, leading to brisk commerce.

The focal point of the tshechus are Cham dances. These costumed, masked dances typically are moral vignettes, or based on incidents from the life of the 9th century teacher Padmasambhava (Guru Rinpoche) and other saints.

Padmasambhava, the great scholar, visited Tibet and Bhutan in the 8th century and 9th century. He used to convert opponents of Buddhism by performing rites, reciting mantras and finally performing a dance of subjugation to conquer local spirits and gods. He visited Bhutan to aid the dying king Sindhu Raja. Padmasambhava performed a series of such dances in the Bumthang Valley to restore the health of the king. The grateful king helped spread Buddhism in Bhutan. Padmasambhava organized the first tshechu in Bumthang, where the eight manifestations of Padmasambhava were presented through eight forms of dances. These became the Cham dances depicting the glory of Padmasambhava.

Most tshechus also feature the unfurling of a thongdrel (or thangka) - a large tapestry typically depicting a seated Padmasambhava surrounded by holy beings, the mere viewing of which is said to cleanse the viewer of sin. The thongdrel is raised before dawn and rolled down by morning.

(source: en.wikipedia.org/wiki/Tshechu)