The Seiryu Clan (星龍会; Seiryu-kai) is a yakuza organization operating out of Yokohama, which is featured in Yakuza: Like a Dragon.
The Seiryu Clan are the biggest yakuza group based in the city of Yokohama. According to the organization's current chairman, Ryuhei Hoshino, the Seiryu Clan was first formed in the immediate aftermath of World War II. Back then, the Clan controlled most of the black markets in occupied Yokohama and protected local businesses from looters in exchange for protection payments.
However, by the 1950's, an organization made of Chinese refugees called the Yokohama Liumang had also began to gain influence in the city and became rivals with the Seiryu Clan. This rivalry almost led to a gang war between the two factions, until a local politician named Yutaka Ogikubo intervened to stop further escalation. Wishing to prevent violence within his constituency, Ogikubo approached the then leaders of the Liumang and the Seiryu Clan and offered to partner with them in a money counterfeiting operation. Ogikubo had acquired stolen plates which the Japanese Treasury used to print 10,000 yen bills and he offered to grant both groups access to them if they joined together to form a counterfeiting syndicate, where the Liumang would import the materials from China, the Seiryu would produce the bills and Ogikubo would use his connections with local government and the police to keep everything covered up. All three of them would split the revenue and peace would be kept between the Seiryu and the Liumang.
Ogikubo's scheme was incredibly successful, since it made him, the Liumang and the Seiryu Clan wildly wealthy. Nonetheless, since the counterfeiting operation had to be kept secret, only top members of both groups were allowed to know about it. This meant that the leaders of both groups had to pretend that there were constant tensions between them which could flare up at any moment. Eventually, when the Korean Geomijul also became a substantial power player in Yokohama, Ogikubo brought their leaders into the counterfeiting scheme as well, giving them the task of producing the counterfeit yen, while the Seiryu handled distributing bribes to key officials to keep the racket secret. This three-way rivalry/secret partnership between the Liumang, the Seiryu and the Geomijul came to be known as the Ijin Three.
In 1973, actor Toshio Arakawa worked as a smuggler for the Ijin Three's counterfeiting operations; moving bribe payments across the country using his acting troupe's travels as a cover. However, his adulterous wife, Yoko, and her lover stole one of the briefcases containing this bribe money from Toshio, causing him to fail to deliver an arranged payment. The Seiryu, suspecting that Toshio had actually stolen the money for himself, sent Hoshino (who was a mere hitman back then), to kill him while he was having dinner with his son. After the Seiryu realized that it had actually been Yoko who'd stolen the money, they had her and her lover murdered as well. As a result, Toshio and Yoko's son, Masumi Arakawa, was left orphaned.
Yakuza: Like a Dragon
In 2019, Ichiban Kasuga and his friends, Yu Nanba and Koichi Adachi, unwittingly uncover that the chief of Seiryu Headquarters, Yamato Totsuka, is running a sinister pension fraud scheme out of the elderly retirement home he operates: Totsuka would kill some of the home's retirees and cover up their deaths so he could continue to cash their pensions and get payments from their relatives. When the Kasuga Party goes to the Seiryu Clan's headquarters to inform Chairman Hoshino about this, Totsuka and several of his goons attack them and try to stop them from reaching their boss' office. Nonetheless, the Party succeeds in reaching Hoshino and revealing the truth. Angered by Totsuka's ruthlessness and the fact that he'd kept this grim business a secret, Hoshino has his captain, Mamoru Takabe, take Totsuka away, beat him half to death and then cut off one of his fingers.
Later on, the second-in-command of the Yokohama Liumang, Akira Mabuchi, falsifies proof that the Seiryu Clan had tried to assassinate him in order to justify going to war with them. In order to start the hostilities, he murders two of Takabe's officers in the middle of the street; prompting the Seiryu Captain to seek vengeance. Hoshino asks Ichiban and his friends to stop Takabe from attacking the Liumang, since he wishes to prevent an all out war between the two groups. The Kasuga Party manages to stop Takabe from attacking the Liumang ringleader, Tianyou Zhao, but when Zhao is told about Mabuchi's betrayal, he demands proof if he's to stop his men from retaliating for Takabe's attempt on his life. In order to get the proof, the Kasuga Party infiltrates the Geomijul's base to gain access to their citywide surveillance system, but they also end up discovering the Korean group's counterfeiting plant.
After Nanba defects from the Party and reveals the counterfeiting to puritan activist group Bleach Japan in order to take revenge on the Geomijul for their alleged murder of his brother, the Geomijul orders Nanba's assassination. The Kasuga Party are called to a meeting with the leaders of the Ijin Three, where the secret pact between all three of them is revealed. Chairman Hoshino insists that Nanba must be silenced to stop the truth about the counterfeiting from being revealed, since its exposure would lead to the collapse of their organizations' primary revenue stream and would leave Yokohama open to an invasion by the Omi Alliance. The Party tries to stop Nanba, but they are unable to prevent him from revealing the counterfeiting secret to Bleach Japan, which is secretly in league with the Omi.
After the truth about the secret pact between the Ijin Three is exposed to the rank and file members of all three organizations, Chief Totsuka tries to stage a coup against Chairman Hoshino. However, Kasuga and his friends manage to beat him and stop his attempts to rally Seiryu soldiers against the Chairman.
After the Geomijul are forced to destroy the counterfeiting operation to stop it from falling into the hands of the Omi Alliance, Ogikubo is coerced by Bleach Japan's leader, Ryo Aoki, into stepping down as Chief of the Citizen's Liberal Party and Diet Representative for Yokohama. When Sota Kume is announced as Bleach Japan's candidate as his replacement in the latter position, the Seiryu Clan covertly backs Ichiban as an alternative candidate in the election. Ichiban runs on a platform of protecting the marginalized people who would be adversely affected by eliminating the gray zones (such as sex workers, the homeless and foreign migrants) and he gains a lot of popularity after trouncing Kume in an impromptu public debate.
In retaliation, Aoki orders Jo Sawashiro to assassinate Chairman Hoshino in order to remove his backing from Ichiban's campaign. The Party attempt to stop Sawashiro but are too late to save Hoshino.
- Ryuhei Hoshino - Chairman
- Mamoru Takabe - Captain
- Yamato Totsuka - Chief of Headquarters, Ryuto Family Chairman
- Kasayama - Lieutenant
- Kikugawa - Lieutenant
- Aida - Lieutenant
- Tetsu - Soldier (New Recruit)
- Koji - Soldier (New Recruit)
- Nagano - Soldier, Senda's Aniki
- Senda - Soldier
- The clan's name directly translates to "Astral Dragon" in English.