Tokyo Underworld, Paperback/Robert Whiting

American Nick Zappetti was sent to postwar Tokyo as part of the Occupation Forces, and soon realised there were certain 'opportunities' to be had there. He opened a pizza joint, became the Mafia boss of Tokyo and the intimate of some of Japan's most notorious underworld figures as well as many of its political and business leaders. This is the secret story of organised crime in Japan as it has risen to world economic prominence.