You know the story: A nameless, mysterious stranger shows up in a desolate town. Two corrupt factions are fighting each other for control without any law to restrain them. The stranger hires himself out to one side, kills members of one family, becomes disgusted with his employers, then makes a deal with the other faction and switches sides. By the end of the story, the town is strewn with bodies, both sides defeated, and the stranger, having cleaned up the town, is triumphant.

You know the story—you may have seen it as a western or a gangster film or a postapocalyptic adventure—even if you’ve never seen the original movie, Akira Kurosawa’s “Yojimbo.” Released in the U.S. 50 years ago and now available in a Bluray edition, “Yojimbo” has proved to be one of the most enduring and influential Japanese films. It has stamped a permanent imprint on popular culture through repeated showings on the arthouse circuit and now on Turner Classic Movies (which recently celebrated the 100th anniversary of Kurosawa’s birth). In the late 1970s, the movie inspired John Belushi’s samurai character, made up to look like “Yojimbo” star Toshiro Mifune, in such “Saturday Night Live” sketches as “Samurai Delicatessen” and “Samurai Divorce Lawyer.”

Kurosawa, who died in 1998 at age 88, was already the most acclaimed and commercially successful Japanese director before “Yojimbo,” thanks largely to “Rashomon” (1950), a film whose title virtually became shorthand for any story told from multiple points of view, and “The Seven Samurai” (1954), which established the samurai epic as a film genre. Their detailed evocation of period and their meticulous and leisurely development of character revealed Kurosawa’s debt to his favorite American director, John Ford. (In his 1982 memoir, “Something Like an Autobiography,” he wrote of Ford that “I would like to resemble [him] as I grow old.” Compared to Jean Renoir and Ford, he felt, “I am no more than a little chick.”) Hollywood, in turn, paid homage to Kurosawa by reworking “The Seven Samurai” and “Rashomon” into westerns: “The Magnificent Seven” (1960), with Yul Brynner, Steve McQueen and Eli Wallach, was one of the biggest-grossing films of that decade; “The Outrage" (1964), with Paul Newman, Laurence Harvey and Claire Bloom, was a critical success but commercial failure.

“Yojimbo,” though, was a radical departure for Kurosawa and, as it turned out, for directors of action movies everywhere. The film opens as if in emulation of the classic western, with the protagonist, played by Mifune—whose real name is never given—warily sizing up the town when a stray dog walks by, carrying a severed human hand in its mouth. This is the samurai’s cue that he’s in a no man’s land where the code and conduct of his profession don’t apply.

In “Shane” and other landmark westerns, the hero always sides with the good guys. The question for Mifune’s swordsman is: Who does a warrior fight for when there are no good guys? The only answer, he quickly discovers, is himself.

“Yojimbo”—the term translates into English as bodyguard—is at once cynical and exuberant. As The New Yorker’s Pauline Kael wrote, “We might expect violence carried to extremity to be sickening; Kurosawa makes it explosively comic and exhilarating.”

According to Audie Bock, author of “Japanese Film Directors” and translator of Kurosawa’s memoir, the film “marked a radical departure in Kurosawa’s mind set from his earlier, more humanistic films. He had become disillusioned with corruption in post-War Japan, and Yojimbo reflected his attitude towards those in power: just kill them all off.”

Which is probably why “Yojimbo,” though it’s set at the end of the last shogun era, which ended in 1867, seems contemporary and not a period film. Corruption and misuse of power is always fashionable—and easily adaptable. In 1964, Italian director Sergio Leone kicked off the era of the spaghetti western with “A Fistful of Dollars,” a virtual frame-by-frame remake of “Yojimbo” as a western with Clint Eastwood in the Mifune role, identified only as “The Man With No Name.” Though Leone denied his film was a remake, Kurosawa sued and received a settlement.

In 1985 Australian directors George Miller and George Ogilvie used the plot line from “Yojimbo” as a model for the first half of “Mad Max Beyond Thunderdome,” with Mel Gibson’s character emerging out of the wasteland and hiring himself out to the two warring factions of “Bartertown” (in a big fight sequence, Mad Max is introduced as “The Man With No Name”).

American action director Walter Hill, openly acknowledging his debt to Kurosawa, transformed “Yojimbo” into a gangster film in his 1996 “Last Man Standing,” with Irish and Italian bootleggers in a Southwestern border town battling it out. Bruce Willis’s gunman, who plays both ends against the middle, calls himself John Smith.

One intriguing question that will probably never be answered is whether or not Kurosawa had an earlier inspiration for “Yojimbo”—Dashiell Hammett’s 1929 crime novel “Red Harvest,” which, because of various legal complications, has never been filmed—though Bernardo Bertolucci, Jack Nicholson, and Neil Jordan, among others, have tried to secure the rights. Set in a Western mining town—an unnamed Western mining town, probably Butte, Mont., where Hammett once worked as a private detective—the plot concerns a mysterious stranger who finds two corrupt organizations fighting for control and. . . well, you know the story.

Film historians are in disagreement over whether Kurosawa took his lead from Hammett. One critic, David Desser, states categorically in his book, “The Samurai Films of Akira Kurosawa,” that “’Yojimbo’ is an adaptation of Dashiell Hammett’s Red Harvest . . . the basic situation that motivates the plot is adapted from Hammett’s novel.” Japanese film scholar Donald Richie, though, told me in a 1996 interview, “I think the similarity in themes is just coincidence.”

If so, cynical minds think alike.

Birmingham native Allen Barra writes about sports and culture for numerous publications including The Wall Street Journal, American Heritage and The Los Angeles Times.