Those directors who return to the same theme over and over commonly use the same actor to embody it. Akira Kurosawa cast Toshiro Mifune as the intense hero in film after film about masculine, if not always traditionally macho, heroism. Juzo Itami starred wife Nobuko Miyamoto as the tough cookie taking on charming, unreliable guys in comedy after comedy satirizing the excesses of bubble-era Japan.

In a similar way, Gaku Hamada has become the go-to actor for Yoshihiro Nakamura, making five films to date with the director since starring as a naive college student in Nakamura’s 2007 “Ahiru to Kamo no Koinrokka (The Foreign Duck, the Native Duck and God).” Diminutive and pixie-faced, Hamada looks more likely to be cast in “The Hobbit” than as the hero in a local commercial film.

But as he shows again in the director’s latest, “Minasan, Sayonara (See You Tomorrow, Everyone),” Hamada is also perfect, and not only physically, as the “little guy” who turns out to be more feisty in a hostile world than he seems at first glance – that is, the center of many a Nakamura film.

He plays Satoru, who has grown up in a danchi — housing projects built in the postwar boom years as self-contained communities. That is, the Japanese version of “workers’ paradises” in the West, as a grainy newsreel illustrates with shots of happy housewives shopping and chatting and happy kids learning and playing — all in the danchi!

So when a 12-year-old Satoru (played by an obviously adult Hamada) tells his ever-patient mother (Nene Otsuka) in 1981 that he plans to spend the rest of his life in the danchi and not attend the junior high school outside it, we half understand why she agrees, though a mystery remains since his decision is not fully explained.

When his former classmates traipse off to their new school, Satoru remains; but instead of vegetating in front of the TV, he embarks on a rigorous regime of study, martial-arts training and patrolling the danchi with a clipboard to make sure all his neighbors are safe, month after month, year after year.

Yes, Satoru is a bit off, but he is also a nice guy, befriending an effeminate boy (Kento Nagayama) who is being bullied at school. He also has a normal sex drive, as he proves when the no-nonsense girl-next-door and his closest confidant (Haru) invites him over for make-out sessions. At age 20 he even finds a girlfriend in the sweet, idol-cute Saki (Kana Kurashina), who shares his desire to stay close to home, and lands his dream job as an apprentice to the gruff master baker (Bengaru) of the danchi cake shop.

But as the years pass and the number of his former classmates dwindle, Satoru’s already small world steadily shrinks. Yet every time he tries to go down the leading to the bigger world outside, he freezes and panics. Will he end up an urban Robinson Crusoe, marooned on his island of concrete?

Based on a novel by Takehiko Kubodera, Nakamura and Tamio Hayashi’s script finds an ingenious answer to this question. And as he did in his 2009 masterpiece “Fisshu Sutori (Fish Story),” Nakumura ties up all the carefully spun plot threads in a brilliant reveal-all ending. Enough to say that Satoru faces a test that is no formula construct, but reflects the reality of a present-day “paradise” poorer and more ethnically diverse than anything imagined in that long-ago newsreel.

At the same time, Nakamura films his boy-to-man story with his characteristic dry humor, though even the gags prove to have a more serious purpose. And personal quirks that at first seem lovably harmless eccentricities turn to out to have a deeper meaning — and surprisingly practical use.

Finally, this film, which starts out quirky and slow, builds to a climax that had me crying hot tears, for reasons I couldn’t immediately explain. Danchi nostalgia, though, had nothing to do with it.