In April 2005, fierce anti-Japanese protests broke out in China.

Triggered in part by Japan's approval of newly revised history textbooks which glossed over the Japanese wartime abuses of six decades ago, the demonstrations were the most provocative upsurge of anti-Japanese unrest China had seen in years.

It was not the first time problems of the historical sort had sparked trouble between the neighbours in North-East Asia.

But researchers at Stanford University's Walter H. Shorenstein Asia-Pacific Research Centre hope that their work will damp down future outbursts and open a path to lasting reconciliation.

Led by director Gi-Wook Shin and co-director Daniel C. Sneider, researchers are completing an ambitious three-year project to examine how the main players in North-east Asia - China, Japan, South Korea and Taiwan - along with the United States, form their views of the past, or what the scholars call "historical memories."

Entitled Divided Memories and Reconciliation, the project began in 2007 and is divided into three phases. The first stage involves comparing how shared historical events are depicted in history textbooks of the five societies, as history education plays a crucial role in shaping citizens' perspectives on the past.

The second stage, which began last year, looks at the treatment of the 1931-1951 wartime period in the films of China, Japan, South Korea, Taiwan and the US.

In the third phase, researchers will survey elite opinion makers in China, Japan, South Korea and the US for their views on historical issues.

The study, said Mr Sneider, stems from the understanding that unresolved historical issues are drivers of regional tension, and continue to bedevil relations to this day.

"The past is very much part of the present. Unresolved problems of the past feed mistrust and suspicion," he told The Sunday Times. "History issues also feed rising nationalism that can undermine government efforts to repair damaged relations."

Despite growing economic and cultural ties, wounds inflicted in the time of war and colonialism still fuel anti-Japanese sentiment in China and South Korea. The outcome of China's civil war resonates today in tension between the mainland and Taiwan.

The goal was not to forge a common historical account for the region or reach a consensus on specific events, said Mr Sneider. He noted that such attempts by historians and government committees have had limited success.

Stanford University historian Peter Duus explained: "Writing a common history is not feasible politically because the teaching of history in East Asian countries is tied to building and strengthening national identity."

Instead, Stanford researchers felt it was more fruitful to "try to recognise and understand how each society has developed its own distinctive memory of the past, and how that has affected its national identity and relations with others", commented Prof Shin.

Prof Duus and Prof Shin were writing in separate chapters included in a soon-to-be-published edited volume on the textbook study. Parts of the book were seen by The Sunday Times.

To facilitate the textbook study, researchers translated into English the most widely circulated high school history textbooks used in China, Japan, Taiwan, South Korea and the U.S.

Focusing on the period from the beginning of the Sino-Japanese war in 1931 until the formal end of the Pacific War with the San Francisco Peace Treaty in 1951, the researchers selected eight historical issues for translation.

These included the Japanese capture and occupation of Nanjing, China in 1937 and the atomic bombing of Japan in 1945.

Researchers included the US in the textbook study because of its participation in the Pacific War, as well as its role in shaping post-war dynamics in the region.

Looking at the translated textbook excerpts side by side would allow people to compare how historical memory is shaped in the different school systems for the first time, said Mr. Sneider.

The team then brought together historians and textbook writers, including those from Japan and China, in a conference in February last year to analyse the treatment of history in thetextbooks, and their impact on regional relations.

The experts found that the region's history texts were far from objective.

"Textbooks have been written specifically to promote a sense of national identity, and the politics of nationalism invariably affects their writing," wrote Professor Shin.

Both Taiwan and mainland China textbooks, for example, play up the victory over colonialism and imperialism. But while "both agree the defeat of the Japanese army ended a century of humiliation and established China as an international power, the path to victory is described differently and so is the outcome," Professor Duus commented.

The deepest disagreements between the mainland and Taiwanese textbooks are about the nature and effectiveness of Chinese resistance to the Japanese. The Chinese texts played down the role of the Kuomintang, while the Taiwanese texts make scant mention of the Chinese Communist Party's guerilla bases.

Compared with the Taiwanese textbooks, the Chinese texts dwelled on the brutality of the Japanese military in more graphic detail.

American textbooks, in general, were better than the Asian textbooks at encouraging critical thought. "You have a debate over the decision to drop the atomic bomb on Japan, or discussions of the events that led to Pearl Harbour, for example," Mr Sneider noted.

In contrast with Chinese and US textbooks, the tone in Japanese textbooks is "muted, neutral, bland", Prof Duus wrote. While they make no effort to conceal the brutality of Japanese forces towards occupied peoples, they do not give students much of an analytical construct to understand events, observed Mr. Sneider.

What the study made obvious was that the problem was not just with the Japanese historytextbooks, even though they have received most of the criticism. Experts point out that the textbooks which whitewashed wartime abuses are used in less than 2 per cent of Japanese schools.

"This is a problem for everybody," said Mr Sneider. "We are all participants in creating a divided, and to some degree, implicitly distorted understanding of the past."

The edited volume on the textbook study - which includes discussions from the February 2008 conference, and translated textbook excerpts - will be out next year. A teaching supplement based on the textbook study has been prepared for use by high school teachers in the US.

Mr Sneider said researchers hoped their work would show that "we need to take a dispassionate, comparative approach to history that recognises there is no single historical truth that everybody has to subscribe to".

He added: "There is room for discussion which can hopefully lead to reconciliation."