"Tobacco harm reduction" is defined as a method to minimize harm and risk of death and disease without eliminating tobacco and nicotine use. In Japan, where heated tobacco products (HTPs) are prevalent, the tobacco industry is progressively endorsing the concept of "tobacco harm reduction." Therefore, stakeholders in tobacco control must urgently share perspectives and experiences surrounding this issue. This discussion paper aimed to propose four requirements for effectively implementing "tobacco harm reduction" as a public health measure: (1) disease risk reduction, (2) cigarette smoking cessation, (3) no additional public health concerns, and (4) regulatory authorities held by health agencies, and compile information on them regarding nicotine-containing electronic cigarettes (e-cigarettes) and HTPs. Another aim was to summarize policies related to "tobacco harm reduction" adopted by an international organization (World Health Organization (WHO) and health authorities in foreign countries (the United States of America (USA), the United Kingdom (UK), Australia, Italy, and the Republic of Korea) to explore the implications of these requirements on Japan's approach. Regarding the first three requirements, scientific evidence indicated that e-cigarettes offers some level of risk reduction and can assist with cigarette smoking cessation. The potential uptake of e-cigarettes among youth and their possibility to serve as a gateway to combusted cigarette use is a concern, though a definitive causal link is yet to be established between the uptake of e-cigarette in youth and the subsequent use of different tobacco products. There is insufficient scientific evidence for any of the three requirements for HTPs. Regarding the official policies, WHO took the position that the same regulations should be applied to all tobacco products. Only the UK and USA officially established a health system based on the concept of "tobacco harm reduction"; even in Italy and the Republic of Korea, where HTPs are relatively widespread, health authorities denied any risk reduction by introducing HTPs. The UK officially adopted a smoking cessation policy with e-cigarettes. The USA established a modified risk tobacco product system under federal legislation enacted in 2009, whereas of June 2023, no HTP or e-cigarettes were recognized as explicitly reducing health risk. Regarding the fourth requirement, the UK and USA institutionalized "tobacco harm reduction" under health authorities' regulation independent of the tobacco industry. The introduction of a tobacco harm reduction policy in Japan should be considered only in line with health authorities' regulation and implementation of comprehensive tobacco control measures independent of the tobacco industry.