BEIJING — With a war chest of $93 million, Zhang Yimou’s latest project, “Heroes of Nanjing,” is the most expensive movie ever made in China, and marks a bold attempt by the leading Chinese helmer to transform the biz here, bringing in Christian Bale and aiming to appeal to both overseas and domestic auds.

Zhang made his name in the West’s arthouses as the banned helmer of “Raise the Red Lantern” and “Red Sorghum,” but was rehabilitated after making “Hero” and “The House of Flying Daggers,” and stage-managing the 2008 Beijing Olympics.

The helmer’s attention in recent projects has been on the domestic market, but “Heroes” is a sign of new international focus.

His long-term producer and partner Zhang Weiping is confident that “Heroes” could do better B.O. abroad than the helmer’s last big overseas hit at the box office, the similar-sounding “Hero,” which took more than $100 million internationally.

“Western audiences loved ‘Hero,’ but while they liked the look of the picture, they had a difficult time getting into the historical Chinese epic theme. So we decided to look for a story with an international core,” the New Picture Film Co. prexy says.

The subject they settled on is the Rape of Nanking, the massacre that followed the invasion of China’s wartime capital, now called Nanjing, on Dec. 13, 1937. Several projects looking have looked at the event in recent years, including Chinese helmer Lu Chuan’s “City of Life and Death” and Florian Gallenberger’s Sino-German co-production “John Rabe.”

“Heroes of Nanjing” is an adaptation of the book “Jinling” by Yan Geling.

“We thought we had found the story,” says Zhang Weiping. “This was in 2006. But the novel itself is not a film script; it needed major surgery to introduce more film elements. We started to work on the script, and it took us three years to accomplish.”

“Heroes of Nanjing” is not only Zhang Yimou’s biggest-budget film in 16 years in the business, he says, at 600 million yuan ($93 million), but it’s also his first time working with a major Hollywood star.

“Inviting Bale to be in the film is mainly targeted at the foreign audience, although he is getting more and more famous in China,” Zhang Weiping says. “He’s the first Hollywood superstar to act in a Chinese movie.”

The negotiation process was a steep learning curve for the Chinese filmmakers, who are used to doing things quickly and on terms that suit them rather than the stars.

“It took two years, as we had to follow Hollywood rules, such as not negotiating with other stars at the same time,” Zhang Weiping says. “If each one needs three to four months to consider the script, it’s already a long time. They are all professional actors; they have very high standards with the script.”

Bale took five months to read and evaluate the script.

“He is so busy, his schedule is fully booked, and he can make money everywhere he wants,” Zhang Weiping explains. “He really has no need to come to China, to do a Chinese film with us. But he loved the story, and he also gave us a lot of suggestions on the script, which inspired us.”

The level of cooperation between Bale and Zhang Yimou was amazing, he says, and the helmer has paid tribute to Bale’s professionalism.

“Our actors really need to learn from those Hollywood actors,” says Zhang Weiping.

New Picture Film is the sole producer, which Zhang Weiping says would keep the production efficient.

He turned away investors looking for a piece of the pic — the booming Chinese economy means the market is awash with capital seeking likely projects to invest in — and opted to borrow money from the Bank of China and Minsheng Bank, and use some internal funding too.

“We wanted to make our film in a pure way, standing back to back and confident. If there are other partners, it is less efficient and harder to make decisions,” Zhang Weiping explains.

“I didn’t consider using foreign investment. I did several co-productions before like “Hero” and “Curse of the Golden Flower,” and I knew a bit about the foreign market, but I didn’t think using foreign funds would help guarantee the movie’s distribution abroad,” Zhang says.

Zhang says he feels the power is in the hands of the audience, not the distributors. “They decide whether they want to pay to see your film in the cinema, they are the decision makers,” he says.

International sales on “Heroes of Nanjing” excluding North America, Japan, Korea and Hong Kong, will be handled by FilmNation.

“I will make a decision at the Toronto Film Festival about the North American distribution,” Zhang Weiping says. “There’s been a lot of interest, including from Universal and Fox, and I hope the film can get released in the U.S. at Christmas and in China on Dec. 16.” n