Eight months on, the diplomatic shock waves from Prime Minister Shinzo Abe's visit to Yasukuni Shrine in December continue to reverberate. The Chinese and South Korean leaders still refuse to meet one-on-one with Abe, with Beijing seeking assurances from Tokyo that the premier will not make another visit to the contentious site as a precondition for talks.

The main bone of contention between Japan and its neighbors regarding the shrine is generally considered to be the enshrinement of 1,068 war criminals, and in particular 14 Class-A war criminals, alongside the souls of millions of Japan's war dead from all the nation's conflicts since 1868. But often overlooked in discussions about Yasukuni is the poisonous role played by the Yushukan, the war museum built within the shrine grounds to promote the nationalist ideology that has become known as the Yasukuni doctrine.

As Koichi Nakano, a professor of political science at Sophia University, explains, this doctrine holds "that all the wars Imperial Japan has fought in modern times were wars of self-defense. Therefore, the people who died while fighting for the country's peace and safety — not only the soldiers, but even nurses and other civilians who were killed on the battlefield — should be commemorated and treated as deities. Also, as a logical conclusion, those conflicts are never treated as wars of aggression."