“It took me eight years to get it together,” director Roger Spottiswoode said of his new film “The Children of Huang Shi” during a recent Dallas interview. The film is based on the true-life story of British journalist George Hogg, who found himself trapped in China during the Japanese invasion of the late 1930s and became the unlikely head of an orphanage in the interior. What’s more, when the invaders approached the school, he led his charges on a 700-mile trek across the mountains to a safe haven near the Tibet-Mongolian border, where he built a new home for the youngsters before dying of tetanus.

“I came on an early draft of the script eight years ago,” Spottiswoode explained. “Actually it was started twelve years ago now. The original story was found by a journalist called James MacManus, who wrote for The Guardian and as a young stringer was sent to Beijing and couldn’t find a story. And at the end of the first week, as he tells it, he was in a bar, a journalists’ bar, in Beijing, and he overheard some other English-speaking journalists complaining that they were going to Shandon, which is an absolutely nowhere town on the edge of the Gobi Desert, because the Chinese government was unveiling a statue to an Englishman, the only statue to an Englishman in China.

“Shandon in the thirties was a rather charming little market town, but by 1980 was a wretched, ghastly, polluted place, as it is now. Anyway, he went, and he found this story. And it’s a remarkable story.

“[He] wrote the article and started gathering information. And actually this year he published his book about Hogg. He’d been slowly gathering information, and after writing the article he eventually wrote a script. Somebody optioned it, and then it didn’t get made. It somehow floated around, and years went by, and it got to some producers. And they came to me and said we think this is a good story. And I worked on it for three or four years with them until it became what I thought was a pretty good script.” Spottiswoode made special use of what he’d learned about the brutality of the Japanese campaign in China while making a film about Hiroshima some years earlier. “It was in the making of ‘Hiroshima’ that I came to understand…what the Japanese were not talking about and what the Chinese find unforgivable,” he said.

Eventually Jonathan Rhys Meyers was cast as Hogg, along with Radha Mitchell as an American nurse he becomes romantically involved with, Chow Yun-fat as a communist partisan who becomes the Englishman’s protector, and Michelle Yeoh as a supportive local merchant, and Spottiswoode went to China to work with a local crew on the project. The children were mostly locals as well, recruited from schools to join the cast.

“We stayed within the spirit of what happened,” Spottiswoode said of the treatment of Hogg’s story, although he admitted that some changes had to be made in the record for dramatic effect and other elements had to be fashioned on the basis of logical inference. “The story was always a very small story, a character story, but it weaves its way through bits of history, and so there are some bigger scenes.,” he added. “And I thought that we had to see those scenes a little bit larger and get a sense that they were on the edges of as war.”

The most difficulty thing about shooting in China, Spottiswoode said, had to do with finding locations that had remained from the time. “The only bits that survived were very, very remote,” he said. “And the only way to get good locations would be to accept that we would lose five or six hours of driving time every day, and I would have to shoot it with much less film. I would plan it much more carefully and shoot very fast.”

The film ends very affectingly as surviving members of the student body from Hogg’s school appear during the final credits to offers their recollections of him. “There are more than forty of them still alive,” Spottiswoode said. “We started tracking them down. Some were in very remote places, some were hard to find, but several of them were in Beijing or Shanghai, or the small cities. And they were fascinated and then pleased that we were going to do a film about George.”

But Spottiswoode hadn’t intended to include footage of them in the picture, and hadn’t even filmed their remarks. “I thought that the thing at the front that says ‘based on a true story’ was enough,” he said. “It never occurred to me to do this ending.”

A preview in Boston persuaded him otherwise. “At the preview, somebody said at the end, ‘Is this really a true story?’ And I said to the audience, ‘How many of you remember that the opening titles said it was a true story?’ and five people put their hands up.

“And I said, oh, that doesn’t work. I called my assistant, who was back in China at the time, and said, ‘Get a little hand camera. I want you to go out and find fifteen of them, and sit them down for half an hour and have them talk to you. I want those interviews in a week.’ And she did it.”