Inside painting, or inner painting, has a history of more than 200 years.

This practice refers to the painting on the inside of a transparent glass or crystal bottle.

The bottle needs to go through a special process where

it is filled with water, carborundum or iron beads,

and then shaken and polished on the inside to make it smooth.

The polished inside of the bottle looks similar to cooked Xuan paper (rice paper).

The craftsman dips the ink into the bottle with the curved hook pen.

It takes a craftsman's exquisite skill.

Song Yunfei, an inner painting artist, has been engaged in the craft for more than 20 years,

His inner paintings cover a wide range of subjects,

including landscape, figures, flowers, birds and calligraphy.

In addition to traditional themes,

he has also integrated some western painting techniques to innovate the art of inner painting.

There is a universe inside the painted bottle.