President Moon Jae-in strongly urged Japan on Thursday to sincerely reflect on its past wrongdoings and apologize for them.

“In resolving the issue of sexual slaves, the Japanese government, the perpetrator, must not say it is ‘over,’” Moon said during a speech marking the March 1, 1919, Korean resistance to Japanese occupation, “Inhumane violation of human rights during war cannot be covered by saying it is over.”

“Dokdo is the land that was first occupied in the process of Japan’s invasion of Korea,” he said, “Japan denying this fact is the same as its refusal to reflect on its imperial invasion of Korea.”

His remarks are a rebuke of the Shinzo Abe administration for playing dumb to Japan’s hideous past and claiming the Dokdo islets.

Japan immediately expressed regret. Chief Cabinet Secretary Yoshihide Suga reportedly stressed the two governments had reached a final and irreversible deal over the issue of wartime sexual slavery. He said Moon’s speech went against the accord and that it was “extremely regrettable” and “unacceptable.”

Tokyo holds fast to its position that it did everything on its part of the deal and that Seoul should keep the promise.

But the Moon administration found crucial faults in the accord, which was signed in 2015 during the Park Geun-hye government. It did not reflect the opinions of former sex slaves. There were unannounced separate agreements seen as favorable to Japan. The Moon administration did not demand renegotiation, considering South Korea’s international trustworthiness. Instead it asked for Japan to acknowledge historical truth as it is and continue efforts to restore the honor and dignity of the victims.

But Tokyo has turned a deaf ear to Seoul’s requests. Prime Minister Abe said Japan would “not move even a millimeter” when it comes to the sex slave issue.

In a recent meeting of the UN Human Rights Council in Geneva, Switzerland, South Korean Foreign Minister Kang Kyung-wha called for a “victim-centered approach” to the issue of sex slaves. Then, Japan reportedly maintained that the issue was settled with the agreement and that it was not confirmed that the Japanese government and military had taken women as sex slaves.

Even a governmental accord cannot undo inhumane war crimes. In this context, Moon said Japan, the perpetrator, cannot say the sex slave issue is over.

In an international conference on wartime sex slaves in Seoul on Feb. 27, a shocking 19-second clip showing Korean sex slaves massacred by Japanese troops was disclosed to the public for the first time. The 19-second footage was taken by the Sino-US allied forces in Tengchong County, Yunnan Province, China, in September 1944.

With this clear evidence brought to the light, Japan must not turn a blind eye to its crimes on Korean women it forced into sex slavery for its troops.

Japan has denied the existence of sex slaves and obstructed civilian activities to commemorate them in the international community.

Influential Japanese figures have denied their country’s historical past including sex slavery almost every year.

Is this a faithful implementation of the accord?

The same is true with the Dokdo issue. Japan’s claims to the Korean islands are becoming conspicuous. In January, it opened an exhibition hall in Tokyo featuring egregious claims to the Korean territory.

Obviously Japan is a country whose cooperation South Korea needs to cope with North Korean nuclear and missile provocations.

But Moon strongly criticized Japan despite the necessity for its cooperation not least for security reasons, because the bilateral ties cannot improve without changes in Japan’s attitude toward the sex slaves deal and Dokdo’s sovereignty.

Moon stressed that he only hopes the two countries will move together for the future as closest neighbors on the basis of a sincere reflection and reconciliation.

Tokyo must not dismiss Moon’s messages as a formality it has heard on March 1 Independence Movement or Aug. 15 Liberation Days. It must take them seriously for the development of bilateral relations.