
Yoshio Yamamori was a Japanese yakuza crime boss who was patriarch of the Yamamori-gumi family of Hiroshima Prefecture from the 1940s to 1950s.
Biography[]
Early career[]

Yamamori in 1946
Yoshio Yamamori was born in Kure, Hiroshima Prefecture, Japan, and he became a prominent black marketeer during and after World War II. Yamamori formed the Yamamori-gumi family with the help of the elder yakuza Kenichi Okubo, and he was initially closely associated with Okubo's Okubo-gumi and Kiyoshi Doi of the Doi-gumi. In 1946, he recruited the Imperial Japanese Army veterans Shozo Hirono, Tetsuya Sakai, Seiichi Kanbara, Uichi Shinkai, Masakichi Makihara, Shinichi Yamagata, and Shuji Yano into his family, and they would come to serve as his underbosses by 1949.
War with Doi[]

Hirono warning Yamamori about the Doi-gumi
That year, Okubo introduced Yamamori to the town councilman Shigeto Nakahara, who offered Yamamori unlimited bank loans in exchange for his help with rigging a council vote against his rival, Shoichi Kanamaru. On Yamamori's orders, Sakai kidnapped one of Kanamaru's allies, and this resulted in the clear defeat of Kanamaru's faction in the ensuing vote. However, Doi found out about Yamamori's culpability after Kanbara drunkenly bragged about the feat at a local bar, causing Doi to storm into Yamamori's bar and attempt to kill Yamamori. Doi was restrained by his underling Hiroshi Wakasugi, and Doi was ultimately forced to leave empty-handed, although he agreed to allow a temporary family exchange between Wakasugi and Kanbara in order to keep the peace as he prepared for his next action against Yamamori.

The Yamamori family gathering to discuss Doi's plans
Yamamori was initially confused as to how to deal with Doi, but Hirono ultimately volunteered to do the deed by himself, even if it might cost him his life, or a return to prison. Yamamori melodramatically thanked Hirono and promised to give him all of his money should Hirono go to prison and ultimately be released; however, while Hirono was hone, Yamamori - manipulated by his wife Rika Yamamori - decided to set up Hirono, whom he was afraid would one day eclipse him. Hirono succeeded in killing Doi, but Yamamori had Kanbara lure Hirono into a trap, where Hirono was arrested by the police. Wakasugi, Hirono's sworn brother, avenged him by executing Kanbara, but Yamamori tipped off the police about Wakasugi's mistress' home, where they tracked down and killed Wakasugi.
Declining power[]

Yamamori in 1954
The 1950s saw the Yamamori-gumi reach new heights of power as the United States military granted the Yamamori family a contract to ship its supplies to South Korea during the Korean War. Yamamori took 70% of his lieutenants' income for himself and, while he notionally opposed some of his lieutenants' involvement in the trafficking of methamphetamine, he secretly sold their confiscated methamphetamine for side profits. In 1954, Sakai and another Yamamori lieutenant, Toru Ueda, demanded that the other lieutenants cut back on their tribute payments to Yamamori; they were opposed by Shinkai and Yano's faction of the family. After Shinkai's subordinate Toshio Arita revealed to Sakai that Yamamori had sold the confiscated methamphetamine on the side, Sakai and Ueda went to Yamamori and demanded that he cede all power to them. Yamamori responded by having Ueda killed, leading to a gang war which saw Sakai destroy Shinkai's faction and become the power behind the throne of the Yamamori-gumi. Yamamori was forced to focus on his business interests as Sakai took over the day-to-day operations of the family.

Yamamori in 1956
In 1956, Yamamori attempted to recruit his other lieutenants to help him return to power. Yamamori ordered Hirono to assassinate Sakai, but Hirono leaked the plan to Sakai rather than shoot him; this led to Sakai blackmailing Yamamori into stepping down as patriarch. Sakai took control of the family and its finances, founding his own investment company. Yamamori, now nominally a private citizen, attempted to regain power once again by turning the rest of the family against Sakai. Yano was assassinated before he could convince the Kaito-gumi to not join forces with Sakai, whom Yamamori feared intended to create his own family, weakening Yamamori's position. While Hirono dissociated himself from Yamamori due to Yamamori's repeated manipulation of him, Makihara ultimately succeeded in having a hit squad murder Sakai at a discount store in February 1956. This allowed for Yamamori to return to power, but Hirono made a scene at Sakai's funeral, where he shot up Sakai's funeral decorations to punish Sakai for his dishonorable behavior, and warned Yamamori that he would shoot him if he attempted to harm him ever again.