In Japan, to become a 'hikikomori' means to withdraw from the world and social life. Many of those who suffer from the condition shut themselves in their bedrooms for years on end, refusing to work, study or interact with anyone around them. More than half a million people are thought to be hikikomori, most of them young men.

One organisation, New Start, has come up with an unusual solution: rental sisters. The sisters-for-hire visit regularly, helping to coax the hikikomori out of their bedrooms and back into society. That could mean just talking through the door, going out for lunch or even moving into a hikikomori boarding house and starting some part time work. Reporter Amelia Martyn-Hemphill finds out about the increasingly popular rental sister phenomenon for BBC World Hacks in Tokyo.

Presenter: Harriet Noble

Photo Caption: A Former Hikikomori