In
Guo Pu's commentaries on the
Classic of Mountains and Seas, he describes this bird as having a purple abdomen and green-tipped feathers, with a long neck and a scarlet beak. This bird acquires its poisonous attributes from devouring the heads of poisonous
vipers. The male and female
zhen are called and , respectively. later lost, yet still quoted in the
Guangyun and the Song-era
Piya dictionary: in those works, the
zhen is described as being
goose-like, colored dark-purple, and having a beak 7–8
cun long and copper-colored; from its very veins to the tips of its feathers, the
zhens body is said to be tainted with a poison of unparalleled potency, referred to as . The
zhens feathers were often dipped into liquor to create a poisonous
draught that was often used to carry out assassinations. Its meat, however, was said to be overtly toxic and gave off a gamy odor that rendered it inadequate for surreptitious use, and the
zhens excrement could dissolve stone. The
zhens poison was said to be so deadly that it needed only to pass through a person's throat to kill them. In the
Baopuzi by
Taoist adept
Ge Hong, the only thing that was said to be able to neutralize the
zhens poison was the horn of the
rhinoceros, which would be made into
hairpins, foaming and neutralizing the poison when used to stir poisonous concoctions. Aside from the
Shanhaijing,
Guangzhi,
Piya, and
Baopuzi, an entry for the
zhen also appears in the
Sancai Tuhui along with a
woodblock print. In the historical records of ancient China, references to the
zhen are usually in the form of the idiom , or when making comparisons between
zhendu and the poison from
monkshood. The idiom is usually meant to describe one who merely considers short-term benefits, not contemplating the grave consequences of their actions. Such references include the chapter "Duke Min's First Year" within the
Zuo Tradition: The
Rong and
Di are like
dholes and wolves and may not be satisfied; the
various Xia states are close intimates and may not be abandoned. Ease and peace are like
zhens poison and may not be contemplated. and in the "Biography of Huo Xu" from the
Book of the Later Han: Would that not be like a person appeasing his hunger by eating monkshood, or quenching the thirst by drinking
zhendu? The person would die as soon as the poison entered his throat, way before they could make their way to his stomach to quench his hunger or thirst. How could [anyone] do such a thing? The 9th century
Wunengzi uses Zhen as a parable for misguided scorn, with Zhen being confronted by a poisonous snake deeming it evil for being such itself. Zhen retorts by stating that it is the snake's poison that it uses, and that it protects people from the snake's bites by hunting them. Therefore, because humans are the ones who use its feathers to kill, it cannot be blamed for what comes from that usage. In Chinese accounts, there are a number of mentions about
zhendu poisoning used in failed and successful assassinations, but because
zhen eventually became a metaphor for any type of poisoning in general, it is not always clear if the bird-poison was actually employed in each case. Various
hagiographic sources relate that Wang Chuyi, a disciple of
Wang Chongyang, was said to have been immune to poisons, even surviving after drinking liquor that contained the
zhendu. In the
Japanese historical epic
Taiheiki,
Ashikaga Takauji and his brother
Ashikaga Tadayoshi force
Prince Morinaga to take
zhendu (
Japanese: ). Later, Tadayoshi was himself captured and poisoned with
zhendu. ==Existence==