Otaku is the phrase used to describe those who love Japanese manga and anime.
To celebrate its global popularity, Tokyo is hosting what organisers are calling the world’s first Otaku summit.
Half a million people are expected to attend the Otaku Expo, with many dressed as their favourite anime characters.
This is the first time that groups from outside Japan have been invited.
People from at least 18 countries and territories are represented at the event, which is similar to some of the Comic Con exhibitions.
The term Otaku was once a derogatory term to describe geeks, but it now reflects the anime-loving community in a far more positive way.