The expedition in search of the medicine for immortality.
The ruler of Qin, Qin Shi Huang, feared death and sought a way to live forever. He entrusted Xu Fu with the task of finding the secret of immortality. In 219 BC, Xu Fu was sent with three thousand virgin boys and girls to retrieve the elixir of life from the immortals on the Penglai Mountain, including Anqi Sheng, who was purportedly a magician who was already a thousand years old. Xu sailed for several years without finding the mountain. In 210 BC, when Qin Shi Huang questioned him, Xu Fu claimed there was a giant sea creature blocking the path, and asked for archers to kill the creature. Qin Shi Huang agreed, and sent archers to kill a giant fish. Xu then set sail again, but he never returned from this trip. The Records of the Grand Historian says he came to a place with "flat plains and wide swamps" (平原廣澤) and proclaimed himself king, never to return.
Later historical texts were also unclear on the location of Xu's final destination. Sanguo Zhi, Book of Later Han, and Guadi Zhi all state that he landed in "Danzhou" (亶州), but the whereabouts of Danzhou are unknown. Finally, more than 1,100 years after Xu Fu's final voyage, monk Yichu wrote during the Later Zhou (AD 951-960) of the Five Dynasties and Ten Kingdoms period that Xu Fu landed in Japan, and also said Xu Fu named Mount Fuji as Penglai. This is the "Legend of Xu Fu" in Japan as evidenced by the many memorials to him there.