Who are grandma Taishan's three sisters?

Grandma Taishan is usually called Bi Xia Yuan Jun. Yuan Jun, Bi Xia is known as the fairy of Mount Tai in Dongyue, commonly known as Mount Tai Empress, Mount Tai Grandma and Mount Tai Mother. Taoism believes that Bi Xia and Yuan Jun "care for all sentient beings, and their spirit should be in Kyushu", "take charge of Yuefu magic soldiers and care for good and evil on earth".

She is an important goddess in Taoism and one of the most influential goddesses in the history of China. Address of Bi Xia Yuan Jun's former residence: Take Bus No.8 in Laoling City and get off at Wangmudian Village. There are temple fairs, sacrifices and other activities during the Spring Festival. Bi Xia Yuan Jun Temple is mainly located in Fangshan District, Pinggu District, Haidian District and Mentougou District. There are five temples dedicated to Bi Xia Yuan Jun; Miaofengshan Niangniang Temple in Mentougou District, Yangpoyuan Niangniang Temple in Tanzhe Temple, Tianxian Niangniang Temple in Zhaitang Town, Jiutian Niangniang Temple in Yanchi Town and Xiangzitai Niangniang Temple; Niangniang Temple in Mu Yi Garden and Niangniang Temple in Xiaguan, Haidian District; Zhuzhong Niangniang Temple in Xicheng District; Niangniang Temple on Daikin Mountain in Pinggu, etc. Among them, there are five municipal cultural relics protection units, Bi Xia Yuan Jun Temple and Fengtai Niangniang Palace. A large temple is dedicated to the statue of Bi Xia Yuan Jun.