The fact that World War Two was a brutal, costly, total war campaign is well-known to even some of the youngest historians still in grade schools across the United States and aboard, with topics from the European, North African, and Pacific theaters covered in units, semester- and year-long classes. What is much more rarely discussed, at least in the United States, is the Asian theater, in which the Empire of Japan invaded and captured the Korean peninsula, the Manchuria region of China, and attacked China itself before Hitler ever invaded Poland in 1939. Part of this is likely due to the Euro- and Amerocentrism of typical history classes in American schools, in which the content taught in these classes are focused on Europe and United States, sometimes to the point of glorification. Indeed, very little is taught about the histories or cultures of other nations and states in American schools, even when this information is pertinent or even critical to the understanding of international events throughout history. The Second Sino-Japanese War, from 1937-1945, is one of numerous events that go unmentioned in American textbooks, including the Nanjing Massacre, which was part of the Imperial Japanese Army’s actions against China.
What is interesting, therefore, is not just American textbooks’ lack of inclusion of that war or event, but also Japanese textbooks’ omission of the event, while Chinese histories make it a point to include what happened in Nanjing before World War Two ever started in Europe, before the West really cared what was going on in the Pacific. It may be that Japan did not want the events of the Massacre to affect their post-war image, something that the United States may have supported in leaving unrevealed due to its own historical events that it is highly reticent to discuss openly, or simply because the US did not want its ally in the area to still seem brutal and ruthless (which Imperial Japan was). However, in spite of this, similar to the United States, Japan has historians who seek to uncover these events, and inject them into the public discussion, such as Ienagu Saburo, whose texts have been censored by the Japanese government for revealing, discussing, and apologizing for the Nanjing Massacre. In fact, there are those among Japanese historians who deny that the Massacre ever took place, contrary to Chinese and revisionist Japanese histories.
Interestingly, some of the treaties signed by Japan to end the War in the Pacific included clauses that Japan had to confess and atone for any war crimes it committed during World War Two. However, due to the fact that the Nanjing Massacre took place in 1938, it’s possible that politicians and some historians have determined that World War Two started in 1939, and as such the event is not included in the war crimes to which it was required to confess and for which it had to atone. Meanwhile, China and its historians have made the Nanjing Massacre almost a rallying cry, demanding that Japan acknowledge the event and atone for it, just as it has for its other war crimes in World War Two, with the Chinese establishing a fairly large and elaborate memorial to the event (the image below depicts but a part of the whole memorial), despite the fact that the historiography – that is, the discussion among historians about what happened – is far from settled even within different perspectives on history.
It is important to acknowledge all histories supported by evidence, and to teach history as an inter-related subject, not isolated to any one nation or state, and to teach those who may take up history as a career, a hobby, or even in classes to evaluate history critically, and form their own judgments based on the evidence they can find for themselves or are presented with by others. That history not be a sterile set of names and dates, but a dynamic understanding of the past and our arrival to the present and its circumstances. To acknowledge and discuss events that may be unpleasant, like the Holocaust, or the Nanjing Massacre, or the genocides and massacres and other crimes against humanity that have taken place since and before World War Two, so that a better understanding, and a better world can be established.
I think that you make a good point about the necessity of evidence based history. With evidence usually comes good history, but I think the events in Nanjing provide an unfortunate example to the contrary. Both sides of the debate on what happened in Nanjing cite “evidence” that looks good enough on the face of it, and it takes a lot of work by professional historians to show why some evidence is being misinterpreted or is not good evidence at all.