This is The Lower Depths but angry. This feels like the closest Kobayashi ever came to making a Kurosawa movie, and it's still distinctly his own. It's a look at people living in the shadow of an American military base on the eve of the American military's departure from the area, when development opportunities are opening up, and what happens to the people in the lowest rungs of society in the face of that. It's also a love-triangle. There's definitely interlapping elements between the two major storylines, both literally and thematically, but I still feel like the two could have been intertwined more intimately.
A slum area of Tokyo welcomes a new resident, the student Nishida (Fumio Watanabe). He has decided to move out here to save some money, finding a cheap place to rent run by an unscrupulous landlady (Isuzu Yamada). On his way, he meets with the pretty Shizuko (Ineko Arima), a waitress who lives in the area. She is also spied by Joe (Tatsuya Nakadai), a local gang leader who decides that he's going to have her. Nishida meets the tenants of the shack of an apartment building, including a husband whose wife he has no idea is a prostitute, a sickly man with a wife, and even some of Joe's gang. That night, Joe sends his gang out to accost Shizuko while she's alone, allowing him to put on a show of saving her from the group of six men. He then immediately rapes her. She is a good girl, though, and knows that he took possession of her. She comes to him the next day and demands that he marry her formally, a prospect that Joe laughs off while taking her on as a kept woman. This causes a rift between Shizuko and Nishida in more ways that one. They were obviously fond of each other in that stranger likes another sort of way, and she had promised to borrow a book from him. With her shame, she runs away from him instead.
Behind all of this is the landlady working with a government official to get the tenants to sign eviction notices because she wants to sell the land to the government for development. Tenant rights in Japan at the time apparently included a provision that each tenant in a tenement had to affirmatively sign off on the eviction for the sale to go through, so the landlady enlists the services of Joe and his men to get those signatures. They're happy to pay three thousand yen for a signature, but they'll commit fraud if necessary. And commit fraud they do, getting at least three fake signatures (as well as stamps, which were apparently a thing) including that of Nishida.
Meanwhile, the relationship between Shizuko and Joe continues with Shizuko obviously trapped in a situation she has no love for, living in rather constant fear, while also trying to find ways to break off just to see Nishida for a few moments whenever she can, but it never works out. He grows increasingly disgusted with the whole situation, and she grows increasingly desperate that she's losing her way out of her depression.
The final major section of the film is really centered on the love triangle while pretty much completely dropping the tenant storyline. There is something going on here that connects the two, though. It's all about how to survive in such a world. Do you keep your innocence, whatever it may be after a crime committed against you, or do you become like Joe? Well, Shizuko chooses one path, and Nishida does not want her to take it. He puts himself in danger to prevent her from doing it, but she does it on the eponymous black river (a stretch of street that is pitch black in the middle of the night). The final shot is just great, by the way. A marvelous composition of stark contrasts in both light and subject.
I think Black River is a good film overall, but the out of balance nature of the two subplots undermines the emotional throughline of Nishida, I think. The center of this film is the degrading effects of this lawless, dog eat dog environment on the people, starting with the presence of Joe and continuing into the degradation of Shizuko. The look at the tenants is another dimension of this same idea, meaning that the two subplots do tie together, but it ends up feeling like extra stuff rather than essential elements to the story. So, it's not quite two movies awkwardly stitched together, but it's close to it. It feels like Kobayashi's typical issue (I wouldn't go so far as to call it a problem) where he has what he wants to say (this time about the lawlessness of post-war Japan that tramples under the underclasses) while trying to find a story to attach to it. The story itself, the romantic trio, actually has all of the subtext that he was looking for, which is interesting in and of itself. Perhaps simply diminishing the tenants in importance while giving us more time with Nishida would have been enough to push this into the upper tier of Kobayashi's body of work.
As it is, though, Black River is the continued evolution of Kobayashi learning to say what he wants to say within a story effectively. He's never been bad at it, and he's made better films, however the strength of the love triangle element's subtext is probably the best he's done at it. The overall package is solidly good, but that love triangle represents some very good work on Kobayashi's part.
