Iwami Shipbuilding is a Japanese shipbuilding company based in Onomichi, Hiroshima Prefecture. The company was founded by Heizo Iwami during World War II, and it was contracted to build warships for the Imperial Japanese Navy. The last contract was to build the Yamato Mark II, a project financed by Admiral Minoru Daidoji using embezzled war funds after the government, considering surrender to the United States by August 1945, cancelled the deal. After the Japanese surrender, the warship was hidden in an underwater drydock to prevent its destruction by the Allies, and it came to be known as the "Secret of Onomichi" as both Japan's highest-classified military secret and as physical proof of Daidoji's involvement in corrupt dealings with Iwami Shipbuilding. Iwami founded the Yomei Alliance yakuza clan to protect the secret and Iwami Shipbuilding's financial interests, and Iwami used the secret to blackmail the Daidoji Faction into passing legislation beneficial to his company. In 2016, the Secret of Onomichi was revealed by Kazuma Kiryu and the Hirose-gumi as part of their quest to bring down the men behind the attempts to kidnap Haruto Sawamura, and this revelation led to Iwami Shipbuilding CEO Tsuneo Iwami murdering his father with Daidoji's backing. He was arrested before he could assume control of the Yomei, leaving his company's future uncertain.