China and Britain have a common responsibility to oppose and condemn words or actions invalidating post-war order

In the Harry Potter story, the dark wizard Voldemort dies because the seven horcruxes, which contain parts of his soul, have been destroyed. If militarism is like the haunting Voldemort of Japan, the Yasukuni Shrine in Tokyo is a kind of horcrux, representing the darkest parts of that nation's soul.

On Dec 26, in flagrant disregard of the feelings of his Asian neighbors, Shinzo Abe, the Japanese prime minister, paid homage at the Yasukuni Shrine, where 14 Class A war criminals defined as those who committed "crimes against peace" are enshrined. They were among the 28 Japanese political and military leaders convicted by an international military tribunal after the World War II.

The Yasukuni Shrine was established more than 150 years ago, and Asian people know very well how it has since been used by Japanese militarists as a spiritual symbol to launch wars of aggression. In addition, it is deeply offensive to witness convicted war criminals being venerated. These were leaders found guilty of inflicting indescribable suffering on countless individuals during the war. Rightly, within hours of Mr Abe's visit, there were strong condemnations from China, South Korea and across the international community.

Visits to the shrine by Japanese leaders cannot simply be an internal affair for Japan, or a personal matter for any Japanese official. Nor does it concern only China-Japan and Korea-Japan relations. Deep down, paying this kind of homage reveals whether Japan is trustworthy. It raises serious questions about attitudes in Japan and its record of militarism, aggression and colonial rule.

At stake is the credit of that country's leaders in observing the purposes and principles of the UN Charter and upholding peace. It is a choice between aggression and non-aggression, between good and evil and between light and dark. Regrettably, what Mr Abe did has raised the specter of militarism again in Japan.

Mr Abe's track record provides evidence. Since taking office in 2012, he has been talking enthusiastically about justice, democracy, peace and dialogue. But the reality is seen in his actions. He is unrepentant about Japan's militarist past and makes no apologies for it. He has openly questioned whether his country should be defined as an "aggressor", and did his utmost to beautify its history of militaristic aggression and colonial rule.

In May 2013, Mr Abe caused great offence in China and Korea when he was photographed posing in a military jet boldly marked with the number 731: this was the code of an infamous Japanese biological warfare research facility performing human experiments in China during the war.