The recovery and repatriation of the remains of Japanese war dead and the roles of physical anthropologists.

During and after World War II, around 2.4 million Japanese died overseas. The bodies of nearly half of them are still missing as they remain in the field where they fell and have never been repatriated. The tasks of recovering and repatriating the remains of Japanese war dead started in 1953 by the former Ministry of Health and Welfare, and are now carried out by the Social Welfare and War Victims' Relief Bureau of the Ministry of Health, Labour and Welfare (MHLW). In 2016, the "Act on Promoting the Recovery of the Remains of Japanese War Dead (Act No. 12 of 2016)" was enacted. The Act designates Fiscal Year (FY) 2016 (from April 2016 to March 2017) to FY 2024 as the period of intensive implementation and stipulates that the state shall establish a process to promote the identification of the war dead. In line with this Act, physical anthropologists were employed as full-time experts by the MHLW to conduct scientific analysis on the remains in the field, and since then, they have accompanied all overseas delegations for repatriation. The authors of this paper have been sent to the sites in the partner countries overseas such as the former Soviet Union, the Philippines, Papua New Guinea, and the Solomon Islands, and nationally to Ioto (Iwo Jima) to analyze the minimum number of individuals (MNI), ancestry, age at death, and sex of the remains. Along with the morphological investigations, DNA analyses of mitochondrial polymorphism and Y-chromosomal/autosomal short tandem repeat (STR) have been applied for estimation of the ancestry and identification of the individual. By narrowing down the possible candidates based on the historical records such as name list of the missing, if individual identification of the remains is achieved, the remains are returned to the bereaved families, and if not, they are placed in the Chidorigafuchi National Cemetery in Tokyo to rest in peace. Also, the implementation of single nucleotide polymorphism (SNP) analyses with next generation sequencing (NGS) for ancestry is under discussion. This paper provides an overview of the process of recovery and identification of the missing bodies from World War II in Japan.