Ckn is used to test the purity of stems. Type "ckn" directly when typing, and you will know what purity is by looking at what your first word is. It is also related to your daily input habits, and it also reflects your daily language to some extent.

This stalk was originally a purity test released by some netizens in places such as Post Bar. Let you enter three letters "ckn" on the keyboard to see what the first word is. The result can be imagined, because everyone's input habits and input methods are different, and the words typed are also varied.