Growing up in Japan, Asayo Iizuka was fascinated by China. So the 22-year-old jumped at the opportunity to study at Shanghai's Fudan University, hoping to expand her knowledge and make Chinese friends.

There she met Chen Li, a 20-year-old economics student at Fudan, who hated Japan. When she was growing up, Ms. Chen's family had told her the Imperial Japanese Army had killed her great-grandfather.

So, at first, a friendship didn't seem possible. "I don't really like the Japanese," she informed Ms. Iizuka early on.

Yet the two women have stayed in touch and each continues to try to change the other's point of view. In the process, they confronted, on a personal level, some of the major issues threatening relations between Asia's two economic giants at a time when slow-growth Japan is finding opportunities in fast-expanding China.

"For 4,000 years China was the top country in Asia, but in the past 150 years, Japan has been more powerful," Ms. Iizuka says. "Now they are equal, but they don't know each other well enough to acknowledge each other."

Even as old wounds linger, China, including Hong Kong, has become Japan's biggest trading partner. About 99,000 Japanese live in China, more than any other country besides the U.S. Both governments are working to nurture better relations among the younger generation. Japan plans this year to set up a fund of 10 billion yen ($86 million) to pay for 1,100 Chinese high-school students to study in Japan annually for about 10 days and an additional 150 for several months to a year. A current government-affiliated study program enrolls 100 Chinese students in Japanese high schools each year.

"The economic relationship is robust and growing," said Jeff Kingston, director of Asian studies at Temple University Japan. "But I don't think that can continue indefinitely while government relations are in the deep freeze."

In China, memories are still strong of the Sino-Japanese war from 1937 to 1945, when the Imperial Army killed at least 10 million Chinese, according to standard estimates. The Chinese complain that Japanese school textbooks skim over the war and object to visits by Prime Minister Junichiro Koizumi to the controversial Yasukuni war shrine in central Tokyo that is dedicated to the 2.5 million people who died fighting for Japan, most of them during Japan's war with China and World War II.

In protest, Beijing has refused to schedule formal summit meetings with Mr. Koizumi and is opposing Japan's bid for a permanent seat on the United Nations Security Council. Thousands of Chinese participated in anti-Japanese demonstrations last spring.

Ms. Iizuka's fascination with China began when she studied the Chinese language in high school. She loved China's ethnic variety and thousands of years of history, and knew the language would help her career. While studying law and politics at a Tokyo university, she went in 2003 to spend a year at Fudan -- the top university in Shanghai.

That winter, a South Korean friend introduced the two women. The students exchanged phone numbers. But Ms. Chen talked little with Ms. Iizuka.

Ms. Chen had disliked Japan since she was a child growing up mostly near Shanghai. From age 7, schoolteachers took her class to see patriotic films; some were about heroic Chinese children risking their lives to resist evil Japanese soldiers during Japan's World War II occupation of China.

In high school, Ms. Chen took part in day-long hunger strikes against Japan. Now, she boycotts Japanese goods, and two years ago bought a digital camera made by a South Korean manufacturer. Buying Japanese products is "a bit like losing face," she said. "We were beaten by them, but now we have to accept their products?"

Ms. Chen bumped into Ms. Iizuka on campus after a winter break. Ms. Chen noticed that Ms. Iizuka seemed different from Japanese students who stuck together and dressed fashionably. Ms. Iizuka dressed down and wore floppy hats, a casual look Ms. Chen found approachable. "She was nice," Ms. Chen recalled. "I thought maybe I should be more open."

The two women found they had plenty in common. They both liked the late Hong Kong movie star Leslie Cheung. Ms. Iizuka treated Ms. Chen to her first Japanese meal, laughing when Ms. Chen flinched at the taste of miso -- bean paste -- soup.

Ms. Chen was beginning to have doubts about the accuracy of some of the information she had about Japan. Ms. Iizuka, meanwhile, felt a special mission to talk about China-Japan relations. In 2002, before her year at Fudan, she had taken a crowded evening train in Manchuria, a former Japanese colony in northeastern China. Fearing for her safety, she told fellow passengers she was Korean.

She later regretted telling a lie and vowed to be more open with the Chinese she met. She had heard about anti-Japanese feeling before she visited China and felt she needed to make a stronger effort to understand Japan's past wrongs. She also felt some Chinese anti-Japan sentiment came from skewed information. For instance, Japan is China's top foreign-aid donor, but China's state-controlled press rarely reports about the financial assistance.

Yet both women held on tightly to certain beliefs. Ms. Iizuka and Ms. Chen had fiery discussions, both in person and over email, over Mr. Koizumi's recent visits to the Yasukuni war shrine. Though the prime minister has apologized for Japan's invasion of China and said his visits are to pray for the souls of regular soldiers, these apologies ring hollow in China because the shrine honors 14 Class A war criminals -- those tried for "crimes against peace," because they led Japan's war in Asia.

Ms. Chen said she was offended by Mr. Koizumi's annual visits. Ms. Iizuka responded that visitors honor relatives killed in action. "They're thinking of their own families," she recalled saying. Mr. Koizumi prays for peace, not for war criminals, she added. Ms. Chen argued that visits by a prime minister are different because "he stands for the country's opinion."

Ms. Chen retained her core feelings about Japan. When anti-Japanese sentiment bubbled up last spring, she joined one of the demonstrations in China. Ms. Iizuka said she was disappointed that her friend had participated, and she wished the Chinese wouldn't blame her generation for past problems. "It's natural for them to criticize Japan's past," she said. "But I can't accept it when they throw this at the Japanese of today. The Japanese of today have done nothing wrong."

Despite the differences in opinion, the two women have remained close. Last fall, Ms. Iizuka visited Shanghai, and they chatted like old friends over lunch in a rooftop restaurant, recalling their past arguments. Ms. Iizuka, who will soon start a job as a wire-service reporter, dreams of working in China one day. Ms. Chen said conversations with Ms. Iizuka have made her less radical. "If I dislike Japan," she said, "it doesn't mean I dislike all Japanese people."