When lists of cinema's old masters are compiled, Japanese director Koji Wakamatsu, now 75, rarely makes them. Perhaps he'd prefer it that way. Going by the antiwar remarks in his director's statement for his latest film, Caterpillar, he remains an extremely angry man. Universal praise has a tendency to fossilize a filmmaker. In Wakamatsu's case, he's reemerged on the world cinema stage after decades of being ignored. United Red Army, now being released in the U.S. three years after it first made a splash at the 2008 Berlin Film Festival, is an epic masterpiece full of tragic grandeur. It's a far cry from the 70-minute B-movies that initially made his reputation, but it retains the same rebellious spirit. The difference between Wakamatsu now and then is that he's also willing to engage with the damage done in the name of that spirit.

Some have already noted that Caterpillar and United Red Army, taken together, form a critique of both the left and right wings of Japanese society. In some ways, it's fitting that they're being released in the U.S. almost simultaneously. Kino Lorber's launching them in New York at the IFC Center, with Caterpillar opening May 6 and United Red Army May 27. The initially disappointing Caterpillar looks better in the light of its immediate precursor. The two films are a history lesson of sorts, taking in a good chunk of 20^th-century Japanese history, from the '40s to the '70s. The conservative nationalism displayed in Caterpillar helps explain the rage of the ultra-leftists in United Red Army.

Koji Wakamatsu's early work is hard to see in the U.S. In France, several box sets of his '60s and '70s films have been released, with introductions by directors like Luc Moullet and Marina de Van, but here, only Ecstasy of the Angels, The Notorious Concubines, and Go, Go Second Time Virgin are available as Region 1 DVDs. His work of this period has points of contact with Jean-Luc Godard and Nagisa Oshima, but its dual commitments to radical politics and explicit sex may explain its difficulty reaching an American audience. When Oshima combined the two in In the Realm of the Senses (which Wakamatsu produced), he had the benefit of an arthouse patina, but Wakamatsu films like Ecstasy of the Angels are unabashed B-movies. On the other hand, they're too cerebral and politically oriented for the psychotronic camp (I can't picture anyone having a good time by getting stoned and trying to laugh their way through them).

United Red Army begins as a docudrama history of the '60s Japanese student left, seamlessly mixing newsreel footage with fictional material shot by Wakamatsu. About 45 minutes in, it concentrates on the United Red Army, an organization made up of several radical student groups, holed up in a mountain hut. Obsessed with the notion of purification via the Maoist practice of self-critique, the United Red Army begins torturing and killing its own members. Finally, the survivors leave the hut and take a hostage in a nearby hotel, directly confronting the police.

United Red Army goes to great lengths to establish the facts behind its story of revolutionary masochism. The causes for which the Japanese left initially fought—opposition to Japanese complicity in the Vietnam War and raises in student tuition—were genuinely righteous. So how did the United Red Army wind up killing each other? The film never editorializes, but it masterfully shifts from a rather dry, journalistic surface to a depiction of the characters' wild sadism. Composer Jim O'Rourke's guitar-driven score evokes Jimi Hendrix and early Pink Floyd.

There's nothing cold or distanced about United Red Army, although the screen is often filled with text, as each new character is introduced by name and age. Its documentary elements recall Peter Watkins, and contribute to a you-are-there immediacy. Once the United Red Army holes up in the mountain hut, the film becomes as suffocatingly intense as Michael Haneke's Funny Games. While there are exteriors during this portion, it's easy to forget them and remember the section as one long torture scene. The film's sustained, nearly unwatchable brutality has few counterparts. As a cri de cœur against 20^th-century tyranny, it does for communism what Pier Paolo Pasolini's Salò did for fascism. United Red Army demonstrates how politics can deteriorate into sadomasochism, played without the safe, sane, and consensual part.

United Red Army was obviously made with a larger budget than Wakamatsu usually has access to. Helicopters circle overhead in some exteriors. However, the heart of the film is quite simple: a confrontation among a group of people. Once the United Red Army reaches the hotel, the mood lightens enough for the film to make jokes about "anti-revolutionary cookies." Yet it never loses sight of its investigation into the darkest aspects of communism. The vast majority of the victims of the Cultural Revolution in China had no choice in the matter. In United Red Army, the situation is somewhat more complicated; while some of the radicals seem caught up in a group that's quickly grown more extreme and vicious than they're comfortable with, others are complicit in the suicidal games of self-critique. Why did the United Red Army identify so deeply with the worst practices of the Cultural Revolution? The film leaves the answer to that queasy question up to the spectator.

Shot in 12 days and edited in 13 hours, Caterpillar is an astonishingly crude, even amateurish-looking, film, for all of Wakamatsu's experience. Even exteriors filmed in the middle of the day turn into shallow-focus murk. Darker interiors are brown and dingy. The dominant color palette is fecal. Careful lighting was clearly not one of Wakamatsu's priorities. It's hard to tell whether this slapdash quality is intentional or a product of the rushed shoot. Yet there's something bracing about Caterpillar's raw blast of anger. It's the cinematic equivalent of a late-'70s anarcho-punk 45.

In its opening scene, Caterpillar shows soldier Kyuzo (Shima Ohnishi) raping a Chinese woman. (The words he uses to describe her are rather less polite.) The building they're in burns down, and he's trapped. Rescued and sent back to Japan, he lives as a quadruple amputee with burn scars on his face and heavy damage to his vocal chords. He expects his wife, Shigeko (Shinobu Terajima), to take care of his needs, particularly his sexual desires. Set toward the end of the Sino-Japanese War and based on a short story by Edogawa Rampo, Caterpillar also exposes the Japanese government's view of wounded men as "war gods" to be put on display.

Wakamatsu's fixation with the materiality of the body here recalls Shohei Imamura, but Imamura never got so blunt. Wakamatsu lavishes loving close-ups on Kyuzo's facial scars and stumps the way a more conventional director might film a starlet's breasts. The very title of Caterpillar indicates the lack of decorum with which Wakamatsu treats his protagonist's body. And make no mistake—Kyuzo is reduced to a body. Shigeko frequently tells him that he does nothing but eat and sleep. If he were fully capable of communication, he might add urination and sex to the list. However, he's reliant on her to fulfill his basic bodily functions. While he still has a penis, he has no hands to facilitate urination or masturbation.

As a political film, Caterpillar shows the hypocrisy of the Japanese government in carting Kyuzo out periodically as a "living war god" but doing nothing for his care. Shigeko frequently spits the phrase "war god" back sarcastically at him. Wakamatsu's rage is refreshing up to a point, but ultimately turns the film into a one-dimensional harangue. The politics of United Red Army are complicated by the director's sympathy for the initial idealism of the United Red Army and intense engagement with their historical background. By contrast, he views World War II-era Japanese nationalism with utter contempt and relatively little interest.

If the Japanese government treats young Japanese men like expendable props, they in turn do the same to women. Caterpillar periodically returns to the opening rape scene, as well as revealing that Kyuzo beat Shigeko before leaving for China. If the film is a tragedy for him, it's a dark comedy for her. Initially, she may be even worse off than she was as a victim of domestic violence. She's called upon to be both madonna and whore. Caterpillar is far from the first Japanese film to suggest that its culture has only two roles for women: submissive victims and dominatrixes. Shigeko navigates between the two positions with ease, expressing her anger at Kyuzo by letting him wet himself and throwing eggs at his face. Yet Shinobu Terajima gives a remarkably nuanced performance—perhaps the only aspect of Caterpillar deserving that adjective—that shows an underlying desire for an equal relationship, impossible under her current circumstances.

Wakamatsu now says that his work researching United Red Army has led him to pacifism, after endorsing armed rebellion in the '70s, and that he wants to tell the stories of conflict between men and women. Caterpillar shows how warfare reproduces itself in the bedroom. In the Middle East and North Africa, students are among those now arming themselves for revolution. In the U.S. and Western Europe, economic problems continue with no end in sight and soldiers head off to fight equally endless wars. The solutions offered by the characters in United Red Army are highly flawed and the characters' view of themselves as a revolutionary vanguard deluded, but the problems they complain about are still real.