By Kate McGeown
BBC News Online
South Koreans have never quite come to terms with the 35 years when the Japanese occupied their country.
President Roh wants to know more about the past
Since the nation was liberated in 1945, there have been few investigations into the widespread collaboration which took place during colonial rule, and the repression of the military regimes which followed.
But now the left-leaning government of President Roh Moo-hyun says the time has come to reveal what really happened.
Unfortunately for him, the first casualty of his campaign was none other than Shin Ki-nam, the chairman of the ruling Uri party which Mr Roh supports.
The president announced his intention to look into Korea's controversial past during a speech last Sunday to mark the 59th anniversary of independence from Japan.
He proposed forming a special committee to look at modern history, particularly during colonial rule and the authoritarian South Korean governments in the decades that followed.
"The anti-national activities of the pro-imperial Japan individuals alone are not the only target," Mr Roh said in his address.
"The encroachment on human rights and the illegal acts perpetrated by past administrations should also be targeted," he said.
According to Korean politics expert Professor Sonn Hochul, from Sogang University, modern Korean history is a subject which certainly needs attention.
"We have never really investigated it properly. After liberation in 1945, any inquiries failed," he told BBC News Online.
"The power-base at the time included Japanese collaborators," he explained, adding that it was not in their interests to investigate the issue.
Kim Hee-sun, chairwoman of the National Policy Committee, said President Roh and the Uri Party were spearheading the initiative "in order to move forward".
According to the Uri Party, South Korea's history has often been changed to serve the administration in power at the time.
Mr Shin resigned as head of the Uri Party because of his father
"Korea's past has been distorted and incorrectly presented, and this has negatively affected our society and culture," Mrs Kim told BBC News Online.
But critics of Mr Roh say his proposal has little to do with recording an accurate version of Korea's past - and much more to do with discrediting his opponents.
Members of the opposition Grand National Party claim the campaign has been launched purely to score points against their chairwoman Park Geun-hye - whose father was the late President Park Chung-hee, an obvious focus for Mr Roh's inquiry.
Park Chung-hee seized power in 1961, in a military coup which toppled the civilian government.
He established martial law and led a regime which - while bringing economic and social stability - is often accused of being oppressive and dictatorial.
But Kim Hee-sun insists the new campaign will not target specific people or power groups.
"If anyone says we are doing this in order to get at someone, then this is not just insulting our efforts but also the wish of the majority of our people," she said.
Mr Roh himself has said that those whose ancestors collaborated with the colonial power - or with the military governments in the 1960s - must not face punishment.
But if Mr Roh's critics are right, and his motivation for launching the campaign was indeed purely political, his plan seems to have spectacularly backfired.
The chairman of the Uri Party, Shin Ki-nam, resigned on Thursday, becoming the first casualty of the campaign.
An enthusiastic supporter of Mr Roh's plan to investigate collaborators, Mr Shin even backed the setting-up of committees to name and shame those who worked for the Japanese.
When it was revealed that his own father had served as a sergeant in the colonial police force, Mr Shin felt he had little choice but to go - even though he claimed the revelation was as new to him as it was to everyone else.
It remains to be seen how many other politicians will have unwelcome reminders of their family histories unearthed as part of Mr Roh's probe into the past.