Germany played no direct role in the worst Japanese atrocities in China. The slaughter of 300,000 civilians in the horrific Rape of Nanjing in 1937 occurred two years before Japan formally joined the Axis Alliance with Nazi Germany. However, the dark, fascist ideologies of racism, imperialism, and the philosophy that "might makes right" were enthusiastically shared by the regimes in Berlin and Tokyo through the 1930s and 1940s. The sufferings of the Chinese people were on a scale comparable with those of the Russian, Jewish and Polish peoples. It is therefore fitting and moving that President Xi wanted to make this comparison publicly.

Another result of President Xi's initiative would have been to contrast Germany's national acceptance of responsibility for the crimes of the Nazi era with the consistent recent policies of Prime Minister Shinzo Abe in Japan. Abe has made clear he is determined to suppress any reference, let alone acknowledgement, of Japan's terrible war crimes. He has done so not just in his public actions and statements, but also in his systematic appointments to the governing board of NHK, Japan's state broadcasting corporation. Nearly 70 years after the end of World War II, these crimes have never been revealed systematically and on a wide scale to the Japanese people. And now under Abe the policies of denial and suppression are being intensified, not abandoned.

Chancellor Merkel made an uncharacteristic and grave error in not accompanying President Xi to the Holocaust memorials in Berlin. The visit would have symbolized the reconciliation of old antagonists. And presented a powerful message to the world about the need for expanded humane international cooperation. Any embarrassment the Abe government experienced would have been salutary, and for its own good. The lessons of memory still need to be learned.

The author is a columnist for the Post-Examiner online newspapers in the United States and a senior fellow of the American University in Moscow.