Why do some people have black and white tattoos?

Because black and white impermanence is Yan's soul-locking ghost, which can subdue all souls.

Tattooing on your body can resist all ghosts and make the wicked feel scared.

White impermanence and black impermanence, also called impermanence Sir Zhong, are gods who specialize in catching evil spirits.

However, there is no specific reason for this. Some people are hobbies, others are beliefs.