Bigu is a Daoist fasting technique associated with achieving xian "transcendence; immortality". Grain avoidance is related to multifaceted Chinese cultural beliefs. For instance, bigu fasting was the
Shennong tasting plants to discover their qualities
Shennong ploughing fields, Han dynasty mural
Han Zhong was a Qin dynasty herbalist fangshi and Daoist xian. In Chinese history, Qin Shi Huang, the first emperor of China, commissioned Han in 215 BCE to lead a maritime expedition in search of the
Transcendent with a flower and Han Zhong riding a deer, Eastern Han dynasty (25-220 CE) tomb tile
Xu Fu's expedition searching for Mount Penglai, Japanese ukiyo-e by Utagawa Kuniyoshi, c. 1843
Repeating crossbow mechanism, Warring States period (c. 475-221 BCE)
Han Zhong, the Bailuxian (白鹿仙; "White Deer Transcendent"), painting by Zhang Lu (1464–1538)