Historical novel based on the "Nissho Maru incident." In March 1953, the Japanese oil company Idemitsu secretly sent the second-generation Nissho Maru to Iran, which was involved in a dispute with Great Britain after nationalizing its oil industry. Loaded with about 22,000 kiloliters of gasoline and diesel oil, the Nissho Maru returned to the Port of Kawasaki in May, greeted by welcoming crowds. In response, the British Anglo-Iranian Oil Company (the predecessor of BP) sued Idemitsu in Tokyo District Court, claiming ownership of the Nissho Maru's cargo. This "Nissho Maru Incident" would be fought out in the courts. The judicial process was reported on in detail in the newspapers day after day, and in the end Idemitsu was victorious, as the Anglo-Iranian Oil Company dropped its case.