烏頭白，馬生角

Chinese

	a crow; black; not a crow; black; not; empty; void	head; (noun suffix)	white; empty; blank white; empty; blank; bright; clear; plain; pure; gratuitous		horse; surname	to be born; to give birth; life to be born; to give birth; life; to grow; student; raw	horn; angle; role horn; angle; role; actor; contend; horn-shaped; Chinese musical note
trad. (烏頭白，馬生角)	烏	頭	白	，	馬	生	角
simp. (乌头白，马生角)	乌	头	白	，	马	生	角
alternative forms	烏白頭，馬生角／乌白头，马生角
Literally: “when crows have white heads and horses grow horns”.

Etymology

From a legend about Crown Prince Dan, who sent Jing Ke to assassinate Qin Shi Huang but failed:

燕太子丹質於秦，秦王遇之無禮，不得意，欲求歸。秦王不聽，謬言曰令烏白頭、馬生角，乃可許耳。丹仰天歎，烏即白頭，馬生角。秦王不得已而遣之。 [Classical Chinese, trad.]

燕太子丹质于秦，秦王遇之无礼，不得意，欲求归。秦王不听，谬言曰令乌白头、马生角，乃可许耳。丹仰天叹，乌即白头，马生角。秦王不得已而遣之。 [Classical Chinese, simp.]

From: Yandanzi

Yàn Tàizǐ Dān zhì yú Qín, Qín wáng yù zhī wúlǐ, bù déyì, yù qiú guī. Qín wáng bù tīng, miùyán yuē lìng wū báitóu, mǎ shēng jiǎo, nǎi kěxǔ ěr. Dān yǎngtiān tàn, wū jí báitóu, mǎ shēng jiǎo. Qín wáng bùdéyǐ ér qiǎn zhī. [Pinyin]

Crown Prince Dan of Yan was held hostage in Qin. The Qin king (who later became Qin Shi Huang) did not treat him well and he was not happy. He then asked the Qin king to let him back to Yan. The Qin king did not listen, and made a bold statement that he would only let him go if the crows have white heads and horses grow horns. Dan looked at the sky and sighed, and suddenly the crows' heads became white and the horses grew horns. The Qin king could do nothing but let him go.

Pronunciation

Mandarin
(Pinyin): wū tóu bái, mǎ shēng jiǎo

(Zhuyin): ㄨㄊㄡˊ ㄅㄞˊ , ㄇㄚˇ ㄕㄥㄐㄧㄠˇ
Cantonese (Jyutping): wu¹ tau⁴ baak⁶, maa⁵ sang¹ gok³

Mandarin
- (Standard Chinese)⁺
  - Hanyu Pinyin: wū tóu bái, mǎ shēng jiǎo
  - Zhuyin: ㄨㄊㄡˊ ㄅㄞˊ , ㄇㄚˇ ㄕㄥㄐㄧㄠˇ
  - Tongyong Pinyin: wu tóu bái, mǎ sheng jiǎo
  - Wade–Giles: wu¹ tʻou² pai², ma³ shêng¹ chiao³
  - Yale: wū tóu bái-, mǎ shēng jyǎu
  - Gwoyeu Romatzyh: u tour bair, maa sheng jeau
  - Palladius: у тоу бай, ма шэн цзяо (u tou baj, ma šɛn czjao)
  - Sinological IPA ^(key): /u⁵⁵ tʰoʊ̯³⁵ paɪ̯³⁵ mä²¹⁴⁻²¹ ʂɤŋ⁵⁵ t͡ɕi̯ɑʊ̯²¹⁴⁻²¹⁽⁴⁾/
Cantonese
- (Standard Cantonese, Guangzhou–Hong Kong)⁺
  - Jyutping: wu¹ tau⁴ baak⁶, maa⁵ sang¹ gok³
  - Yale: wū tàuh baahk, máh sāng gok
  - Cantonese Pinyin: wu¹ tau⁴ baak⁹, maa⁵ sang¹ gok⁸
  - Guangdong Romanization: wu¹ teo⁴ bag⁶, ma⁵ seng¹ gog³
  - Sinological IPA ^(key): /wuː⁵⁵ tʰɐu̯²¹ paːk̚² maː¹³ sɐŋ⁵⁵ kɔːk̚³/

Idiom

烏頭白，馬生角

(literary) when pigs fly

Related terms

馬生角／马生角 (mǎ shēng jiǎo, “impossibility”)
天雨粟，馬生角／天雨粟，马生角 (wū tóu bái mǎ shēng jiǎo, “impossibility”)
天粟馬角／天粟马角 (tiān sù mǎ jiǎo, “impossibility”)
(Min Nan) 天落紅雨，馬生角／天落红雨，马生角 (thiⁿ lo̍h âng-hō͘, bé seⁿ kak, “impossibility”); 天落紅雨，馬發角／天落红雨，马发角 (thiⁿ lo̍h âng-hō͘, bé hoat kak, “impossibility”)

Descendants

→ Japanese: 烏(う)頭(とう)白(しろ)くして馬(うま)角(つの)を生(しょう)ず (utō shiroku shite umatsuno o shōzu) (calque)