Before that it is necessary to prepare ourselves with a new Chinese character "穴".
Let us see its evolution history first as usual (image get fromhttp://www.vividict.com):
|Learn one Chinese Character a day - 穴|
Oracle Script , looks like the image , which is a Pictograph character. (象形 xiàngxíng: Pictographs, in which the character is a graphical depiction of the object it denotes. Examples: 人 "person", 日 "sun"). It means "Cave in a mountain".
Seal Script is still similar as Oracle Script , however when it evolved further to Clerical Script , it was simplified to what is using now - "穴".
"穴" means Cave,
It also has extended meanings, such as "Hole" or "Burrow"
It is now time to enjoy a Chinese Calligraphy with 穴 inside: