Denial of the Nanjing Massacre is a negationist claim asserting that the murder and rape of hundreds of thousands of Chinese soldiers and civilians by Imperial Japanese forces in Nanjing is a fabrication or exaggeration. Most historians accept the findings of the Tokyo tribunal with respect to the scope and nature of the atrocities which were committed by the Imperial Japanese Army after the Battle of Nanjing during the Second Sino-Japanese War. In Japan, however, there has been a debate over the extent and nature of the massacre, with some historians attempting to downplay or outright deny that the massacre took place.

Experts hold differing estimations for the total death count. Some think it could be as low as 40,000, but most historians think it was somewhere between 50,000 and 300,000. The International Military Tribunal for the Far East has said there were at least 200,000 deaths. Some scholars, notably negationists 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.Fogel, Joshua A. The Nanjing Massacre in History and Historiography. 2000, page 46-8Dillon, Dana R. The China Challenge. 2007, pp. 9–10 These negationist accounts of the killings have become a staple of Japanese nationalist discourse.Yoshida, pp. 157–158 The massacre is also only briefly mentioned in some Japanese school textbooks. Scholars have also said that the Japanese version of the Wikipedia article () emphasizes negationist narratives.

Some Japanese journalists and social scientists, such as Tomio Hora and Katsuichi Honda, have played prominent roles in countering Nanjing Massacre denialism in the decades after 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.Gallicchio, Marc S. The Unpredictability of the Past. 2007, page 158

China–Japan relations are affected negatively by denial of the massacre, as it is seen in China as part of an overall unwillingness on Japan's part to admit and apologize for its aggression, or a perceived insensitivity regarding the killings.

The international academic community generally agree the Nanjing massacre happened and concur on the wide scale of the event. The basic facts have an overwhelming consensus among historians. Although there are still some arguments over the details of the event, such as the exact number of victims, most historians still recognize the scale and nature of the massacre after post-war investigations. These conclusions are supported by a large number of testimonies and archives. As a result, denialists and revisionists who deny or downplay the nature and scale of Nanjing massacre are usually not considered to be mainstream in academic research.

National identity Takashi Yoshida asserts that, "Nanjing has figured in the attempts of all three nations [China, Japan and the United States] to preserve and redefine national and ethnic pride and identity, assuming different kinds of significance based on each country's changing internal and external enemies."Yoshida, p. 5

Japan In Japan, interpretation of the Nanjing Massacre is a reflection upon the Japanese national identity and notions of "pride, honor and shame". Takashi Yoshida describes the Japanese debate over the Nanjing Massacre as "crystalliz[ing] a much larger conflict over what should constitute the ideal perception of the nation: Japan, as a nation, acknowledges its past and apologizes for its wartime wrongdoings; or ... stands firm against foreign pressures and teaches Japanese youth about the benevolent and courageous martyrs who fought a just war to save Asia from Western aggression."Yoshida In some nationalist circles in Japan, speaking of a large-scale massacre at Nanjing is regarded as Japan bashing' (in the case of foreigners) or 'self-flagellation' (in the case of Japanese)".

The academic community is increasingly paying more attention on the role that digital medias such as Japanese Wikipedia play in shaping the public consensus of Nanjing Massacre. The researchers found that the online content are showing the tread of historical revisionism more frequently. They narrated the event selectively and using a controversial view to interpret the historical resources. Meanwhile scholars and editors are actively countering such revisionist narratives by emphasizing the evidence norms and historical writing standards base on primary sources. Askew(2007) emphasizes that in the investigations of Nanjing massacre, it is crucial to conduct a critical assessment of the testimonies and other evidence that can be regarded as primary sources. He also warns against the interpretations which mainly driven by political agendas instead of rigor analysis of the content. This assertion is aligning with boarder efforts created by historians and editors which resists historical denial and distortion. A recent research that operated by Wikimedia foundation (2022-2024)indicated that Wikimedia among different versions of languages are continuously correcting the content that have a tendency towards historical revisionism through moderation and editing practices.

China David Askew, an associate professor of law at Ritsumeikan Asia Pacific University, characterizes the Nanjing Massacre as having "emerged as a fundamental keystone in the construction of the modern Chinese national identity". According to Askew, "a refusal to accept the 'orthodox' position on Nanjing can be construed as an attempt to deny the Chinese nation a legitimate voice in international society".

Taiwan (Republic of China)

Former Taiwanese President Lee Teng-hui had, on numerous occasions, claimed that the Nanjing Massacre was purely propaganda perpetrated by the Chinese communists and which could be placed into the same category as "fictitious history"; a position which has stirred controversy in both mainland China and Taiwan. However, Lee's comments are generally regarded as his personal political interpretation instead of general consensus of mainstream Taiwanese historical community. In Taiwan, Nanjing massacre is widely recognized as a historical event of the Second Sino-Japanese War, even though the interpretations of its political significance can be different among different political parties. Taiwan's historical research on wartime memory are generally tending to adopt a transitional narrative perspective instead of historical denial. The majority of Taiwan scholars resist revisionism. Therefore, in academic literature, Lee's opinions are usually viewed as politically controversial rather than representative positions of Taiwan as a whole. Lee had spent the first 22 years of life in Taiwan under Japanese rule, serving as a military officer when the island-nation was still under Japanese rule. In general, attitudes in Taiwan towards Japan are more positive than in the PRC due to the longer and less harsh Japanese administration of Taiwan compared to the Japanese occupation in the PRC. Furthermore, the geopolitical alignment of Taiwan and Japan against the PRC mean that the perception of Japan is less influenced by Japanese actions in WWII and more influenced by contemporary Japanese cultural exports.

The rest of the world, outside of China and Japan, has largely dismissed attempts to downplay the Nanjing Massacre. Most historians in the US and Europe agree with the findings of the International Military Tribunal for the Far East. Historian Daqing Yang notes a growing consensus among experts that Japanese soldiers were responsible for large-scale atrocities in Nanjing, and that the mass killings of Chinese prisoners of war were ordered, not random. Western scholars place the Nanjing Massacre into the context of Japan's other wartime atrocities, comparing those who deny it to others who distort history. Refusing to acknowledge the massacre hurts China–Japan relations, as it is seen as part of Japan's reluctance to admit to its past mistakes in Asia. This issue remains a major point of tension between the two countries, with many in China feeling that Japan has not done enough to make amends for its actions during the war.

Issues of definition

The precise definition of the geographical area involved, duration of the massacre, as well as who is to be considered and counted among the victims, forms a major part of both the definition of the massacre and the arguments of denialists. Among the most extreme denialists, casualty claims range from several dozen to several hundred.Denialists say that few civilians were killed, and that the massacre is a fabrication. Nankin gyakusatsu' no kyokù" (The "Nanking Massacre" as Fabrication). Masaaki Tanaka, a denialist, engaged in academic misconduct to support his claim that the massacre was a fabrication and death tolls were low. However, figures within the range of 50,000–300,000 are typically articulated among more sophisticated and mainstream historians. The International Military Tribunal for the Far East estimated at least 200,000 casualties and at least 20,000 cases of rape.

The common revisionist viewpoint, made by denialists such as Higashinakano Shudo, is that the geographical area of the incident should be limited to the few square kilometers of the city, and they typically estimate the population to be about 200,000–250,000.Tanaka, Masaaki. What Really Happened in Nanking: The Refutation of a Common Myth. Tokyo: Sekai Shuppan, 2000. pp. 16-17 However, this geographic definition is almost universally unheard of outside of revisionist circles. Their use of 200,000–250,000 civilians also only includes those in the Nanjing Safety Zone, which does not include everyone inside of the city.

Most historians include a much larger area around the city, including the Xiaguan district (the suburbs north of Nanjing city, about 31 km2 in size) and other areas on the outskirts of the city. In 2003, Zhang Lianhong estimated that the population of greater Nanjing was between 535,000 and 635,000 civilians and soldiers just prior to the Japanese occupation. In 2008, he revised his estimate to 468,000–568,000. Some historians also include six counties around Nanjing, known as the Nanjing Special Municipality. With the six surrounding counties included, the population of Nanjing is estimated to be more than 1 million.Historian Tokushi Kasahara states "more than 100,000 and close to 200,000, or maybe more", referring to his own book Nankin jiken Iwanami shinsho (FUJIWARA Akira (editor) Nankin jiken o dou miruka 1998 Aoki shoten, , p. 18). This estimation includes the surrounding area outside of the city of Nanking, which is objected by a Chinese researcher (the same book, p. 146). Yutaka Yoshida concludes "more than 200,000" in his book (Nankin jiken o dou miruka p. 123, Yoshida Yutaka, Tennou no guntai to Nankin jiken, 1998, Aoki shoten, , p. 160). Professor Tomio Hora at Waseda University in Tokyo writes 50,000–100,000 (Tanaka Masaaki, What Really Happened in Nanking, 2000, Sekai Shuppan, , p. 5).

The duration of the incident is naturally defined by its geography: the earlier the Japanese entered the area, the longer the duration. The Battle of Nanjing ended on December 13, when the divisions of the Japanese Army entered the walled city of Nanjing. The International Military Tribunal for the Far East (IMTFE) defined the duration of the massacre as the six weeks following the fall of Nanjing on December 13, 1937." More conservative estimates say the massacre started on December 14, when the troops entered the Safety Zone, and that it lasted for six weeks.

Most scholars have accepted figures between 50,000 and 300,000 dead as an approximate total. Negationists in Japan, however, have contended at times that the actual death toll is far lower, or even that the event was entirely fabricated and never occurred at all.