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
moan and groan without being ill - wú bìng shēn yīn
laws handed down from forefathers - zǔ zōng fǎ dù
can compose and perform military exercises - shàn wén néng wǔ
quick flow of writer 's thoughts and imagination - tù qǐ hú luò