千鈞一髮

Based on a passage in Liezi:

• 龍誑魏王曰：『有意不心。有指不至。有物不盡。有影不移。髮引千鈞。白馬非馬。孤犢未嘗有母。』 [Traditional Chinese poetry, trad.]

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  龙诳魏王曰：『有意不心。有指不至。有物不尽。有影不移。发引千钧。白马非马。孤犊未尝有母。』 [Traditional Chinese poetry, simp.]

  From: Liezi, 1^st – 5^th century CE

  Lóng kuáng Wèiwáng yuē: ‘Yǒuyìbùxīn. Yǒuzhǐbùzhì. Yǒuwùbùjìn. Yǒuyǐngbùyí. Fàyǐnqiānjūn. Báimǎfēimǎ. Gūdú wèicháng yǒu mǔ.’ [Pinyin]

  Long deceived the King of Wei, saying: "There are intentions (concepts) but these are not minds. There are zhi (pointings out, significations, representations) but these do not reach (things). There are things but they are not exhausted. There are shadows but they do not move. A hair draws (a weight of) one thousand jun. [A] white horse is not [a] horse. An orphan calf never had a mother."

Later used to metaphorically mean "a crucial and emergent moment" in Book of Han & by Tang dynasty's writer Han Yu (Chen, 2014):^[1]

• 夫以一縷之任係千鈞之重，上縣無極之高，下垂不測之淵，雖甚愚之人猶知哀其將絕也。 [Traditional Chinese poetry, trad.]

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  夫以一缕之任系千钧之重，上县无极之高，下垂不测之渊，虽甚愚之人犹知哀其将绝也。 [Traditional Chinese poetry, simp.]

  From: The Book of Han, circa 1^st century CE

  Fū yǐ yīlǚ zhī rèn xì qiānjūn zhī zhòng, shàng xiàn wújí zhī gāo, xià chuí bùcè zhī yuān, suī shènyú zhī rén yóu zhī āi qí jiāngjué yě. [Pinyin]

  Although I am clumsy, I know the danger to tie a hundredweight to a thread up to the [roof]less sky and down to the bottomless abyss.

• 其危如一發引千鈞 [Literary Chinese, trad.]

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  其危如一发引千钧 [Literary Chinese, simp.]

  From: 韓愈 Han Yu 〈與孟尚書書〉, "Letter to Secretary Meng", included in 《全唐文》 The whole collection of Tang period literature, Vol. 553

  Qí wēi rú yīfāyǐnqiānjūn [Pinyin]

  It is so emergent like a hundred weight hanging by a hair.

千鈞一髮

1. imminent peril; a matter of life or death; to be hanging by a hair