The assumption of Bill Guttentag and Dan Sturman's Nanking, like that of many pedestrian documentaries, is that in describing painful things, the work is accomplished. So: In December 1937, the Japanese invasion of China led the army to Nanking, where for the first six weeks of their occupation they followed the rule of "The Three Alls": "Kill All, Burn All, Loot All." Over 200,000 civilians were killed and 20,000 raped, making the Rape of Nanking one of the 20th century's most severe yet least remembered atrocities.

In helping to rectify this failure of the public memory, Nanking is no help at all. Diligently itemizing rapes and mutilations, it tells you everything and nothing. Irony and complexity are dead words here; only the most viscerally repugnant events are considered. While Nanking may be under-remembered, it's not undocumented either: something more than a tear-inducing atrocity exhibition is called for.

Instead, Nanking glosses over its subjects' many interesting complications. The Japanese announced their invasion with air raids over Shanghai; Radio Shanghai responded by playing Beethoven's "Funeral March," a mortuary's paid advertisement conceived in dubious taste. As the Japanese ground troops advanced towards Nanking from Shanghai, an unlikely coalition of foreigners decided to create a safety zone to shelter as many civilians as possible. One, John Rabe, was a dedicated Nazi businessman who puzzled over why the Führer wouldn't intervene when his kindness and concern for all peoples of the world was famous. Alongside more conventional do-gooders like Americans surgeon Bob Wilson and Minni Vautrin, headmistress of a missionary college, Rabe managed to save, depending on how you count, as many as 200,000 civilians.

Much of Nanking is the simple listing and description of atrocities, which quickly fade into each other. Teen girls are raped, mothers have their breasts chopped off, baby buttocks are skewered. There will be blood. What's missing is why this matters: Does hearing something described at great length make it comprehensible? The most revelatory footage in the film is old Japanese soldiers describing, with no apparent remorse or emotion, their participation in the bloodshed; the unfathomable contrast between their reserve and the words coming out of their mouths is more revealing than any of the emotion shed by Chinese interviewees recalling the past. To feel good about yourself as a viewer, you can identify with the understandable pain of the victim, but you learn nothing -- that victimization sucks is a given. Looking beyond the most obviously horrific stories -- to find something that is not obvious -- is the task Nanking shirks; its Japanese soldiers are there to fill in background detail. It all blurs together: "Sometimes one gets weary of suffering," Vautrin wrote in a letter. It's true even if you're experiencing it vicariously.

A granola PBS-style history I could have lived with, but it's the celebrity factor that makes Nanking close to unwatchable. Instead of having the letters and diaries of the foreigners read in voice-over, we get close-ups of actors of varied skill sitting in business attire and performing what seem like barely rehearsed monologues. Few negotiate the challenge of how to discuss atrocity without succumbing to emotional pornography (Jürgen Prochnow comes close; Woody Harrelson seems to not even be trying), but something's gone very wrong when I spend more time thinking about Mariel Hemingway's eyebrows than the words coming out of her mouth. Hemingway is an appalling actress; she sighs after every other line, working extra hard to convey inner turmoil and the weariness that comes when hell on earth is the status quo.

Undercutting the testimony of the real victims and soldiers, these melodramatic hams push Nanking from well-intended history lesson into a bizarre exercise in Brechtian alienation. What's more important, eyewitness accounts or bad performances by semi-famous thespians, both unrevealing? Nanking offers up the worst of both worlds.