Once in a blue moon

Once in a blue moon

Once in a hundred, Chinese idiom, Pinyin is B ǎ IB ù y ī y ù, meaning less than once in a hundred times, describing extremely rare. It comes from Han Ji Ai Di Ji Xia by Xun Yue of Han Dynasty.

The origin of Idioms

In Han Ji Ai Di Ji Xia written by Xun Yue of Han Dynasty, it is said that "when a policy is made, there will be no blame or regret. If this happens once in a hundred, it will never be as good as what one knows and sees."

Idiom usage

As a predicate or attribute.

Idiom explanation

Not once in a hundred. It's extremely hard to describe. 　　

Analysis of Idioms

Synonym: once in a century.

Antonym: easy to get.