Koichi Adachi (1960-) was a Japanese policeman, driving instructor, and security company executive. Based in Yokohama, he was fired from the Kanagawa Prefectural Police in 2019 for helping Ichiban Kasuga investigate the Omi Alliance and its ties to TMPD superintendent Juro Horinouchi, only to help expose Horinouchi's corruption and found the successful Adachi Investigative Services.
Biography[]
Koichi Adachi was born in Yokohama, Japan in 1960. He served in the Kanagawa Prefectural Police and took down the Yokohama Pink Panthers burglary gang in Isezakicho during the 1990s, but, after leaking evidence that revealed that a suspected murderer named Kusumi was falsely arrested by corrupt TMPD officer Juro Horinouchi, he was demoted to work as a driving instructor. Kusumi hanged himself in prison, and a guilty Adachi sent money to his orphaned son Takashi for years.
Adachi helping Kasuga break into the Heian Tower
In 2019, Adachi investigated the falsely imprisoned Ichiban Kasuga ahead of his release from prison, discovering that he had taken the fall for another yakuza gangster's murder of Chikao Suzumori shortly after midnight on 1 January 2001. Adachi enlisted Kasuga's help with investigating Horinouchi's corruption, and, although Kasuga was initially insistent on rejoining the Arakawa-gumi, Adachi caught up with him in Kabukicho, Tokyo and revealed that the Arakawa Family had left the Tojo-kai for the Omi Alliance, which by then controlled Tokyo. Adachi later helped Kasuga storm an Omi officers' meeting to confront his former oyabun Masumi Arakawa, and Adachi's stalling of a police helicopter sent to investigate the break-in resulted in his firing from the police force.
Adachi followed Kasuga to Isezakicho, Yokohama now that he was unemployed and joined him, the homeless man Yu Nanba, and the hostess Saeko Mukoda in their investigation of the murder of soapland owner Isao Nonomiya, the role that Yokohama Liumang strategist Akira Mabuchi played in his death, Mabuchi and the Omi Alliance's plot to start a gang war and take over the city, and later Tokyo governor Ryo Aoki's role in masterminding the Omi's takeover of Tokyo and invasion of Yokohama. Adachi remained a steadfast ally of Kasuga, leading to the assassin Mirror Face briefly disguising himself as Adachi as part of an assassination attempt on Kasuga at Reiji Ishioda's hideout. Kasuga identified Mirror Face after realizing that the assassin, unlike Adachi, was an expert on traffic laws, and he defeated the Adachi lookalike. As Kasuga prepared to confront Aoki in Tokyo, Adachi put Kasuga in touch with his old friend Makoto Date, who lent them New Serena as a hideout. During the storming of the Millennium Tower, Adachi discovered a memory drive containing proof of Masumi Arakawa's bribery of police officials, and he confronted Horinouchi with the evidence after sending its contents to the inspector general, watching as his nemesis was arrested for his crimes.