How did the police interact with (1) the yakuza as depicted in Confessions of a Yakuza, (2) the citizenry during the Pacific War, and (3) the general public, as depicted in Cultural Norms and National Security?
As we are limited in space, below are a few ideas to help get you started.
One thing to understand the yakuza, Japanese mob, or organized crime unit, is that in the past the yakuza was really not the same as the Italian or Russian mobs, mostly due to Japanese customs. Peter B. E. Hill in The Japanese Mafia: Yakuza, Law and the State defines the yakuza as a “set of firms that provide extra-state protection to consumers in primarily, but not exclusively, the illegal market sector” (p.10). According to Peter Hessler of The New Yorker, generally, the yakuza was not violent, and if it ever was, the violence was only towards a fellow yakuza member. Should a yakuza member murder a fellow yakuza member, the murderer would actually turn himself into the police station and only be sentenced to prison for two or three years because it was not treated as the same as murdering a regular citizen (A Review of The Japanese Mafia by Caryl Lynn Segal). Since the yakuza was seen as non-violent, the police generally left the yakuza alone. If the police did perform a raid on a yakuza gambling facility, the police would even warn the gang prior to the raid, giving the members the chance "to hide particularly damning evidence" ("Yakuza and the Police").
Even in Confessions of a Yakuza by Junichi Saga, in the chapter titled, "Resisting the Law," the police were portrayed as being a lot more lenient on the mob, depending on mob activities, than we see it necessary for police to be when it comes to the violence of the Italian and Russian mobs. The raid on the gambling facility was a lot more peaceful than Western civilization would picture. The customers and mob members would not resist the raid because resisting would mean tougher sentences. The only reason why the police made an arrest is because the author, Saga, put up a fight by pulling on a ceiling light and shutting off all the power, allowing for all customers and mob members to clear out. Due to the sabotaged raid, the police felt embarrassed, so they went to the mob leader asking him to turn in whoever "blew the fuse."
The one aspect of police treatment that varies from Western practices concerns the use of torture for confessions. Saga explains that the police use torture on yakuza to get them to confess to the crime of illegal gambling. They would not use torture on the customers to get confessions because the customers would be more likely break in court and say that they only confessed to gambling due to torture and then the case would be thrown out, and the investigating officer in charge would have been dismissed. If the yakuza had broken in court like the customers, the police would have cracked down on the yakuza even more as revenge for getting an officer dismissed or transferred. If the police were to crack down on the yakuza, they would have started 24-hour stake outs, which would have chased away any gambling customers, deterring the yakuza from making their living (p. 91-92).
Hence, we see that while the Japanese police were generally relaxed concerning the yakuza because they were generally non-violent, they also used brutality that would not be permissible in Western society.