In her almost nine years as chancellor of Germany, Angela Merkel has won respect around the world for her dignified leadership, strong moral sense and disciplined, responsible fiscal policies. In her willingness to stand by unpopular but essential fiscal policies during the eurozone crisis, she has often appeared to be the last adult left standing among the current crop of European national leaders.

It is all the more disappointing, therefore, that Merkel's government has declined two Chinese requests to include Holocaust memorial sites in the official itinerary of Chinese President Xi Jinping in Berlin starting on March 28, the Memorial to the Murdered Jews of Europe - the city's largest Holocaust memorial site and the Memorial to the Victims of Fascism and Militarism on the Unter den Linden boulevard.

Merkel's record of fully acknowledging Germany's own horrendous record of genocide during the Nazi regime of Adolf Hitler has been consistent, courageous and admirable. It is securely rooted in the responsible positions taken by the leaders of democratic, modern Germany since the Federal Republic was first established under Konrad Adenauer in 1949.

Merkel has never shown the slightest reluctance to acknowledge the horrors of the Holocaust when any Israeli leader has visited Germany. Why, then, her refusal to publicly do so with President Xi? The answer clearly does not lie in any German desire to bury or deny the facts of the Holocaust. Instead it rests on an obvious political calculation. As the British newspaper The Daily Telegraph pointed out on March 5, "Berlin fears that it will be drawn into an embarrassing row between Beijing and Tokyo over Japan's perceived failure to acknowledge past war crimes."

The government of China has been trying to impress the world with the sharp contrast between post-World War II Japan and Germany in facing their parallel burdens of history. Both nations carried out war crimes involving the systemized extermination of scores of millions of human beings that were without precedent in modern history. At least 11 million people, including 6 million Jews, are generally accepted as having been systematically murdered in the Nazi genocidal programs. The most recent extensive research by the American Holocaust Memorial Museum in Washington, DC, suggests that the death toll was even higher, 20 million in all. Countless Russians, Poles, gypsies and other nationalities were also murdered during those nightmare years.

Little noted in the West was the comparable slaughter inflicted by the Imperial Japanese Army during its eight years of conquest, occupation and suppression campaigns in China from 1937 to 1945. Certainly 16 million Chinese non-combatant civilians were slaughtered. Some estimates put the figure as high as 20 million. Hundreds of thousands of peasants were systematically and deliberately infected with the most horrific bacteriological and other biological war compounds by the infamous Unit 731. After the war all the doctors and scientists of Unit 731 were quietly cleared by US occupation authorities in Japan, so that their research and "expertise" could be appropriated by the United States in its Cold War struggle with the Soviet Union.

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.