Nanking Massacre denial is the denial that Imperial Japanese forces murdered hundreds of thousands of Chinese soldiers and civilians during the Second Sino-Japanese War, a highly controversial episode in Sino-Japanese relations. It is considered a revisionist viewpoint and is not accepted in mainstream academia, even within some Japanese academia. Most historians accept the findings of the Tokyo tribunal with respect to the scope and nature of the atrocities committed by the Imperial Japanese Army after the Battle of Nanking. In Japan, however, there has been a heated debate over the extent and nature of the massacre. Relations between Japan and China have been complicated as a result, as denial of the massacre is seen as part of an overall unwillingness on Japan's part to admit and apologize for its aggression, or a perceived insensitivity regarding the killings. Estimates of the death toll vary widely, ranging from 40,000 to over 300,000. Some scholars, notably the revisionists in Japan, have contended that the actual death toll is far lower, or even that the event was entirely fabricated and never occurred at all. These revisionist accounts of the killings have become a staple of Japanese nationalist discourse.
In Japan, only a small but vocal minority deny the atrocity outright. Some Japanese journalists and social scientists, such as Tomio Hora and Katsuichi Honda, have played prominent roles in countering revisionist historiography, in the decades since the killings. Nonetheless, denialist accounts, such as those of Shūdō Higashinakano, have often created controversy in the global media, particularly in China and other East Asian nations. Coverage of the massacre in Japanese school textbooks also troubles Sino-Japanese relations, as in some textbooks, the massacre is usually only briefly mentioned.