Tokyo's Shinjuku entertainment district hides a criminal underworld known by a name that strikes fear into the hearts of many Japanese, Yakuza. "The Yakuza are feared because of their violence....They don't even have to commit an act of violence. People know that they are capable of it. They are ruthless and they will commit violence against you, if you don't do what they want," said Jeff Kingston, director of Asian studies at Temple University, Japan Campus, in an appearance on the National Geographic documentary series, Taboo.