Yoshimune's Plan (Season 5)
Yoshimune's objective was to acquire Majijo and Ryuutou's land for Akechi Group's development project.
To this end, he took advantage of Principal Mori's hatred of yankiis and presumably arranged for him to have a gun to assassinate Salt. Japan's gun control is very strict and a schoolteacher is unlikely to have one, and Yoshimune has an online store that sells guns. He also told Otabe that he was selective to whom he provided guns and ammo.
He knew that the Ryuutou Clan would be under suspicion due to their earlier conflict with Majijo, although many did acknowledge that the idea of them killing a high school student for beating them in a fistfight was ridiculous; Ryuutou would then either be weakened by the war against Majijo or be disbanded by the police, which either way would make them more easily pressured to sell their land. As reassurance, he also provided Bakamono, a Majijo graduate who worked at his company, with a gun and disavowed her connection with Akechi Group. Whether she pulled the trigger or not, she would have to be killed before her connection to Akechi Group was discovered, which is what Urasawa did. At the same time, Salt's death would weaken Majijo's yankii leadership, making them less likely to resist their school being shut down, since Majijo's owner was already open to the idea. The plan worked, which Otabe sarcastically applauded, although Yoshimune did regret that his daughter being a Majijo student meant that she was also in harm's way.
Knowing that the Chinese mafia could betray Akechi Group at any time, he also had documents incriminating them as insurance. In the event of his death, he prepared a contingency plan in which weapons and the documents would be delivered to Otabe, allowing her and her friends to eliminate that threat by giving the documents to the police and also protect themselves if necessary. Ironically, his death by the Triad's hand happened with the cooperation of both his right-hand man Urasawa, who was second in line for succeeding Akechi Group's leadership, and Akechi himself, who considers him too dangerous.
Reclaiming the documents had been the Triad's objective since the beginning. Unfortunately, they knew that Majijo had a connection to Akechi Group through Akechi's friendship with Majijo's owner (another thing Yoshimune overlooked) and set their sight on them after eliminating Yoshimune, correctly suspecting that they somehow had the documents. Many viewers blamed Sakura for starting the war with the Triad by assaulting one of their bases, but actually they would have gone after Majijo anyway (although her actions did make them take her more seriously as a threat).
They went as far as murdering Yoga after interrogating her about the documents (which she didn't know about) and then kidnapped Magic and demand the documents as ransom. Majijo students chose to take matters into their own hands rather than handing over the documents or involving the police, whom we know are mostly corrupt anyway, except maybe Nirasawa, and even he has hinted that he isn't above using the yankiis to fight the Yakuza and Triad groups.
