It’s not your typical viral hit. Self-directed, self-funded, and shot mostly on a simple camcorder, the film follows the lives of coal workers in rural Hunan, a central Chinese province.

But “Miners, the Horsekeeper, and Pneumoconiosis” has become an unexpected sensation among Chinese documentary fans after its director took a creative approach to publicizing the feature.

In late March, a small group of documentary enthusiasts on the popular review site Douban received direct messages from the filmmaker Jiang Nengjie. He sent them links to a file-sharing site where they could download his new movie for free.

The move proved to be a stroke of genius. Within days, thousands of people had watched “Miners, the Horsekeeper, and Pneumoconiosis,” given it a high rating, and shared the link to download it with their friends.

“The director follows you back and sends a private message explaining how to watch his film,” one shocked user posted on Douban. “What’s made our documentary makers do this?”

Giving away work for free appears natural to Jiang. Throughout his career, the 35-year-old has been an advocate for two things above all: standing up for marginalized communities and not compromising freedom of expression.

For the self-described diaosi — a slang term referring to members of the Chinese underclass — indie documentaries are vehicles for exposing the truth.

“What’s ‘independent’ first and foremost? In my eyes, it’s free expression, which is an inherent human right,” Jiang tells Sixth Tone during a phone interview. “I need to speak up. I can speak with my mouth, and I can also speak with my documentaries.”

Since 2009, the filmmaker has released several titles focusing on the plight of the “left-behind” children of China’s migrant workers. An ongoing series tells the life stories of army veterans who feel they’ve been forgotten by society. Another new project looks at China’s LGBT community.

The issues he explores in the 83-minute film “Miners, the Horsekeeper, and Pneumoconiosis” hit even closer to home.

Pneumoconiosis, more commonly known as “black lung disease,” is an incurable occupational ailment that mainly affects coal miners. Around 6 million people in China have the disease, according to Beijing-based charity Love Save Pneumoconiosis. It remains a toxic legacy of decades of breakneck economic development and lax work safety regulations.

Jiang is from a mining family, and almost all of his male relatives suffer from pneumoconiosis to varying degrees. The “horsekeeper” from the film’s title refers to his own father; the owner of the illegal iron ore mine is his cousin; and Zhao Pinfeng — the dying middle-aged miner — is from a village next to his hometown in Hunan province.

The film offers a frank portrayal of life in Hunan. It takes viewers up slippery mountain paths, down illegal dusty mine shafts, and around lunch tables where miners crack crude jokes and swap stories of local corruption and injustice. Then the second half of the film shifts focus on the impending death of a family’s sole breadwinner.

Yet “Miners, the Horsekeeper, and Pneumoconiosis” has enjoyed almost overnight success — an even more impressive feat, given the challenges facing China’s indie documentary makers.

As the government’s oversight over the cultural sector has tightened in recent years, filmmakers have found themselves forced to choose between altering their work to secure a public release, or reaching a tiny audience in the underground cinema scene. Chinese indie-doc filmmaking is widely perceived to be in decline, with mainstream audiences increasingly intolerant toward narratives depicting the dark sides of society.

“Some people seem to think that removing those who point out problems also gets rid of the problems themselves,” says Jiang.

Jiang’s success is likely to be a one-time deal. Baidu Cloud, the storage service where copies of the film are stored, is required by law to clean up illegal or unapproved content on its site. Old links to the documentary have already been scrubbed from the internet. Fans, however, keep sharing new links — so many, Jiang says, he can’t even keep track of them.

Sixth Tone discussed with Jiang to find out how he made “Miners, the Horsekeeper, and Pneumoconiosis,” why he chose to release it the way he did, and what the film reveals about China’s economic development. The interview has been edited for brevity and clarity.

Sixth Tone: How did you end up releasing the film for free online?

Jiang Nengjie: Initially, it was fellow documentarians and media friends of mine that reposted it. People clicked the “want to watch” button on the film’s Douban page, so I sent it to them. A friend said it’d be difficult for me to recover the production costs, so I attached a QR code to the messages at his suggestion.

People sent me tips through the QR code to show their respect. I told them online screenings should be cheap, because I couldn’t give them a theater-level experience. But they said, “It’s OK, you can send me your future films if they can’t be released via ‘ordinary channels.’ Just treat this as a preorder.” I was quite touched.

Sixth Tone: How did you develop the idea for this documentary?

Jiang: When I started shooting this film in 2010, I just found it interesting. Others didn’t have the same access to the mining community. Many of the miners are related to me, so I could easily join them and enter the mines.

Of course, I knew about pneumoconiosis. But I didn’t deliberately focus on that. I just filmed the miners. But by 2014, it had become increasingly obvious that miners were suffering from pneumoconiosis. Many people in the village spat up blood and died. After that, I began shooting with more purpose.

We locked in on this particular family, and the protagonist died within just a couple of years. We knew he wouldn’t live long, but we didn’t expect the cause to be a power outage. When the electricity went down, his oxygen machine stopped.

Sixth Tone: What was the most challenging aspect of making this film?

Jiang: The lack of funding was the hardest. Half of the money I spent on the camera was borrowed. Every now and then, I’d run out of money and would have to take a break from shooting to earn more.

Sadly, some of the best scenes I shot aren’t in the film, because the camera ran out of batteries or the memory card was full. There wasn’t anywhere to charge them in the mountains. That left me with a lot of regrets.

When it snowed, it was very slippery in the mountains. One time, a man I was filming tripped and almost fell down the steep slope. If he’d fallen, he almost certainly would have died. I was standing right next to him, and my hand holding the camera was shaking.

Sixth Tone: What do you want the audience to take away from your film?

Jiang: This group receives far too little coverage in the media. We shot the film hoping to call attention to the prevention of occupational diseases. It’s necessary for miners to wear masks. Factories and enterprises are responsible for their workers’ health. They come to offer their labor, not their lives.

We also wanted the public to see that the disease is very serious. Some feedback I received was that people hadn’t heard of pneumoconiosis patients in China, and yet it’s such a huge group. I hope people see that these people aren’t having it easy and they treat migrant workers better.

Pneumoconiosis patients aren’t just people who work in illegal mines. Many build highways, high-speed railways, and high-rise buildings. These people made great efforts and sacrifices for our economic development but don’t have basic protections. It’s not supposed to be like that.

Sixth Tone: How do you navigate China’s stringent film screening approvals process as an independent filmmaker?

Jiang: We have to fight to express ourselves in films. If you don’t push the boundaries and ask, “Why can’t I keep this?” the authorities will gradually encroach even more. There’s little space left for us.

From the reaction to my film, it appears the public is hungry to see these kinds of things about our country and its sufferings. There are still quite a few people in our country who want to see the reality of life in China, not just the gaodashang — the grandiose. I can’t make those films. As a diaosi, this is my kind of style.

Editors: Qi Ya and Dominic Morgan 

(Header image: A screenshot from “Miners, the Horsekeeper, and Pneumoconiosis.” Courtesy of Jiang Nengjie)