<Kokodo> written and illustrated by Jay Eunji Lee,

Has been published in Korea, 2016.

This picture book is about the gender equality for children.

Proboscis monkeys learn a special martial art which came down from their grandfather.

They realize that there is no difference between female and male in terms of their ability while learning the martial art. 

They also learn that they are all equal and they can be stronger when they are together.