Mirror Flower, Water Moon, (simplified Chinese: 镜花水月; traditional Chinese: 鏡花水月; pinyin: Jìnghuā Shuǐyuè)/Kyōka Suigetsu (鏡花水月, literally "Mirror Flower, Water Moon")), is an East Asian proverb/phrase, meaning something that cannot be grasped, like a flower reflected in a mirror or the moon reflected on the water's surface; you can see them, but you cannot touch them, something that is beautiful but unattainable dreams, a mirage.
This name references 鏡中的花，水裡的月, which is the shorter form of a Chinese idiom, (or chéngyǔ), literally meaning a "flower seen in the mirror, moon on the water's surface".
Modern popular culture
In the popular anime series Bleach, Sōsuke Aizen's sword that allows him to manipulate other character's senses and perceptions is called Kyōka Suigetsu.