A once in a blue moon
Chinese idiom, Pinyin is Qi ā NZ ǎ IQ í y ù, which means to describe extremely rare encounter. From the story of heroes and heroines.
The origin of Idioms
Chapter 38 of Wenkang's biography of heroes and heroines in Qing Dynasty: "it's a once in a blue moon to have a son who is willing to be taught."
Idiom usage
It's hard to meet. example this is a real adventure.
A once in a blue moon
Fire and water are incompatible - shuǐ huǒ bù xiāng róng
have no other intention until death - zhī sǐ mǐ tā
fulfill part of one's daily routine - xū yìng gù shì
with a bloody nose and a swollen face - bí qīng liǎn zhǒng
gathering in crowds and groups - chéng qún zhú duì