Several cases of Japanese children with past-life memories have come to light since they began to be studied systematically in 2000. The cases closely resemble cases of children with past-life memories reported from other parts of the world, although as yet the previous incarnation has been identified in very few Japanese cases with stranger relationships between the past and present lives. Most solved Japanese questions have occurred among relatives.
Some archaeological and cultural facts suggest that people in Japan of the Jomon period (14,000-300 BCE) had a belief in reincarnation: infants were placed in a pot, possibly likened to the womb, and buried upside down near or inside dwelling places, possibly showing the family members' wish for the dead child to reincarnate.1 This conjecture appears to be supported by the fact that ‘very similar funeral customs have been observed in some rural areas of Japan even recently’.2
The earliest written reference to the notion of 'reincarnation' was made after the arrival of Buddhism in the sixth century in Shomangyo Gisho, an annotated commentary on the Srimala Sutra, written in 611.3 Then, numerous reincarnation stories under the influence of Buddhism came to be reported, arguably the oldest ones being those included in Nihon Ryoiki written in the early Heian Period (794-901),4 but all were ‘rewarding good and punishing evil’ type of legends or folktales. The first investigative report was that of Katsugoro in the nineteenth century.
Numerous uninvestigated reincarnation stories have appeared in recent years. Within the framework of folklore studies, Matsutani collected more than thirty such stories from all over Japan.5 A number of stories, mostly provided by the children’s mother,6 have been reported by Ikegawa Akira, whose focus is on prenatal memories in general, and by Iida Fumihiko, an economist who argues that the knowledge of spiritual reality including reincarnation can help create meaning and value in life. The notable reported case of Noriya, interviewed by Ikegawa, is described in the ‘unsolved Japanese cases’ section below.
Ohkado Masayuki began in 2000 to study Japanese children claiming past-life memories using the methods of Ian Stevenson, and since that date he has discovered and investigated many such cases, as summarized below. Ohkado has written more extensively about some cases only in Japanese, but he has published reports of several in English, notably for the Journal of Scientific Exploration.
Japanese Cases with Family Relationships
This is a rare case involving abortion.7 In 1989, Ao’s grandmother, Tomiko, who had already had two children (a son and a daughter), had to abort the third child when she found she was three months pregnant. Following a Buddhist tradition she held a memorial service for the aborted soul, displayed the ‘proof of service’ in the living room, and made it a practice to pray for the spirit. In 2016, Tomiko's daughter gave birth to Ao. When Ao was two years and three months old, he said: ‘Before I was born, I was with mom, grandpa, grandma, and Hie [the name of Tomiko's son].’ He mentioned his grandparents and Tomiko’s son (his uncle), who lived separately from his mother, and did not mention his father, who has been with him: The family members he mentioned were exactly those present when Tomiko aborted the third child.
At around the same time, when Ao visited Tomiko, he pointed to the ‘proof of service’ and said: ‘That is me, and you should now discard it’, appearing to imply that now that he was back, his grandmother no longer needs to pray for the spirit (now incarnated as Ao). Ao insisted on wearing blue pants, and according to Ayumi, his mother, who had regularly seen spiritual entities when she was young, Ao with blue pants looked exactly the same as the child spirit who had been around the house. She had not known about the aborted child at that time, but she now believed that he had been the aborted child's spirit and returned to her mother (Ao's grandmother) as Ao.8
This is a case in which a deceased girl appears to have been reincarnated as her brother. Kanon's sister Momoka died of leukemia in January 2004 at the age of six. Shortly before her death, in the car driven by her mother from the hospital she had been back to her home, Momoka ‘promised’ her mother that she would write a letter with words: ‘Are you OK? Aren't you lonely?’ The case involves two possible announcing dreams.
(1) In 2008, Momoka's mother had an impressive dream, in which her favourite band played a song with a beautiful melody and lyrics. A couple of days after the dream, she turned on the TV to find that in a variety program, the band was about to sing a new song. The title of the song was ‘Hana no Nioi (The Scent of Flowers)’, which the mother thought was suggestive of her deceased daughter being around since ‘ka’ in ‘Momoka’ means ‘flower’. The lyrics of the song was suggestive, to the mother, of her return: ‘Even if this is goodbye forever / I can hear your breathing / I just know that in some other form, with that same smile / You'll come to see me again.’ Eleven days after this, she found that she was pregnant.
(2) Her husband repeatedly had the same dream, in which two girls were laughing joyfully in the wood, one of whom he interpreted as Momoka coming back. (The other he regarded as Momoka's friend who had died before her.)
Kanon was born in July 2009. He resembled Momoka physically and his behaviours reminded his mother of Momoka: He liked flowers; his favourite colour was pink; he showed interest in girls’ toys and had a toy cosmetic set with a lipstick, comb, mirror, and ribbons; he asked his mother to tie his hair with a pink ribbon; he had toy rabbits, which were also Momoka's favourite toys, and played with them in the same way as Momoka did. When he was four, he said: ‘I was once burned,’ appearing to talk about the cremation of Momoka’s body. He also said that the wall colour of the house used to be much darker, which was correct, since the colour of the wall was dark brown when Momoka was alive, but it faded and was light brown when Kanon talked about it. Three months after the remarks, he came to his mother saying: ‘I have written a letter to mom.’ The words in the letter were: ‘Mom, are you OK? Aren't you lonely?’ Kanon had not said explicitly that he had been Momoka until May 2020: When he was with his parents in the living room, he said: ‘I was Momoka before’, and he made the same remarks while he was with his mother.9
This is a case in which a young man who had passed away by committing suicide appears to have returned to his mother by being born to his sister. His past-life personality, Jun, got into trouble with gangsters and eventually committed suicide by jumping from a bridge over a highway in December 1997 at the age of 21. Kazuya was born in April 2004 to Jun's brother. Kazuya made a number of remarks and showed behaviours suggesting that he was the reborn Jun. He called his great-grandparents in the way Jun had called them, and his grandmother ‘mom’ as Jun did, not ‘grandma’ as expected. When Jun’s best friend came to his home on the anniversary of his death, Kazuya called her by the same nickname as Jun had. During an asthma attack, Kazuya said: ‘I can’t breathe, but I won't die. I will live this time.’ He also said, ‘I could have died of a disease, but I wanted to die early. I didn't face my disease at that time, so I'm now facing it.’
In response to his grandmother's question: ‘Were you Jun?’, Kazuya said: ‘When I was born from Mom, I was Jun. But now I am Kaju [Kazuya]. I am Kaju now.’ After the funeral and cremation of his great-grandmother in 2016, Kazuya insisted on carrying the urn in which the ashes were placed until he and his family were back home. He said: ‘I have finally fulfilled the promise with her I couldn't fulfil before’, which means: When he was Jun, he promised his grandmother that when she became too old to walk, he would carry her on his back, but because of his early death, he couldn’t fulfil his promise. Now as Kazuya he is carrying her [her ashes in the urn] and has fulfilled the promise. An interesting feature of this case is that the child talked about what he experienced after he committed suicide.10
This is a case in which a child apparently remembered two miscarriages his mother underwent. Takuma was born in April 2009. In 2015, when he was six years old, while he was eating snacks with his mother in the living room, he said casually: ‘I entered mom’s belly twice, but died. But I looked for it again, and I was so happy that I was able to find it.’ His mother had two miscarriages, once in 2002 and once in 2004, which Takuma had no way of knowing. In 2018, when he was eight years old, he surprised his elementary school teacher by writing about his two ‘deaths’ in an essay in which he was supposed to express his gratitude to his mother.11
This is a case in which a mother appears to have come back to her daughter as a daughter of the latter about three years after her death. Tae was born in May 1996 as a second child of Atsuko. Atsuko’s mother (Tae's grandmother) Midori, who enjoyed inviting and entertaining guests with foods and gifts, had died three years before Tae’s birth. She had worried about Midori, who had been suffering from depression up until about one year after Midori's death.
When Tae was about two years old, Atsuko, her mother, happened to show Tae a picture of Midori, saying: ‘This is your grandmother.’ In reply, Tae said: ‘It’s me.’ Although this was the only occasion when Tae explicitly said that she was Midori reborn, she showed some characteristics that reminded Atsuko of her mother: she had fastidious taste in clothes; she was fond of and good at drawing pictures; whenever the house hosted guests, she got excited and gave a big welcome to them; and she expressed great ‘mother-like’ attention to Atsuko. Related to the last point, Tae showed impressive behaviours at the age of three when Atsuko was suffering from a relapse of depression. One day, when Atsuko took a walk around the house with Tae, holding her hand, she heard Tae muttering: ‘I have to cheer her [mother] up. I have to cheer her up.’ Upon hearing this, Atsuko strongly felt that Midori, who had been showing concern about her mental condition, came back to take care of her again.12
This is an experimental birthmark case in which a deceased uncle appears to have been reborn as his niece. When Tomiko was born in April 1954, the midwife in charge of the birth let out a gasp of astonishment, noticing a round reddish birthmark, possibly about 3 centimetres (1.2 inches) in diameter, on the back of the baby's neck. The mother, who was worried by the midwife’s reaction, immediately noticed the birthmark and was scared that the child might have a serious handicap or disorder. Her concern was relieved when she heard from her husband that the birthmark corresponded with the circle he had drawn on his brother’s neck when he had died of dysentery at the age of three in 1934, and that the child must have been his brother reborn. Tomiko did not make any statements suggesting that she was her uncle reborn, but she was exceptionally big and healthy just as her uncle had been.13
Japanese Cases with Stranger Relationships
This is one of the best documented historical cases of the reincarnation type. It is the subject of a separate article in the Psi Enclyclopedia and is only briefly summarized here.
Katsugoro was born in 1815. When he was eight years old, he started to tell his family about having lived before in a nearby village as a boy named Tozo, who had died of smallpox at the age of six, five years before he was born. Many of his statements turned out to be true, and, since he repeatedly begged his family to take him to his former house, his grandmother eventually took him to the village. On the way, Katsugoro guided his grandmother to the house where Tozo used to live and met his former family. He convinced Tozo’s parents that in fact he was their son reborn.14
Sakutaro was born in August 2012. When he was three year old, as his mother was putting him to sleep, he said: ‘Mom’s voice is not very cute. The voice of the former mom was cute.’ Then he started to make statements about his past life as a young man who had an accident while riding a motorcycle and later died at a hospital. He talked about some details about his former mother, the type of motorcycle he was riding, had knowledge of the games which was popular about twenty years before he was born, and drew a detailed picture of the accident. Sakutaro's mother, who felt urged to find the mother Sakutaro was talking about to comfort her by showing that the ‘dead’ son was actually ‘alive’ (reincarnated), tweeted about Sakutaro’s story and begged for information. Some pertinent information was sent to the mother, and the past-life family was apparently identified. Although Sakutaro's mother attempted to contact the family, they refused to talk with or even receive written messages from her.15
Takeharu was born in May 2012. When he was two, as he was taking a bath with his mother, he said: ‘I won’t die. I won’t die before you. You cried a lot because I died, didn’t you?’ He loved to play with a toy ship in the bathtub in a peculiar way: he ended up his play by sinking the ship as if it were attacked. When he was three, he started saying: ‘I want to see Yamato,’ which made no sense to his parents. When he was four, he made the following remarks which seemed to suggest that he was talking about the Japanese battleship Yamato, one of the two largest battleships of the Imperial Japanese Navy. (In 1945, immediately after the Allied forces invaded Okinawa on April 1st, Yamato, together with nine other ships, was dispatched to protect the islands, but on the way to Okinawa on 7 April, it was repeatedly attacked by American Navy carrier airplanes and sunk.)
Among other things, Takeharu said:
- ‘There was a great ship.’
- ‘It exploded.’
- ‘I was drowned.’
- ‘We were attacked and defeated as we went to help.’
- ‘Nobody knew about the ship.’
- ‘The left side of the ship was attacked again and again.’ [The American airplanes concentrated on attacking the port side of Yamato.]
- ‘I found Musashi! He is (my/our) brother!’ [‘Musashi’ is the sister ship (in Japanese the ‘brother ship’) of Yamato.]
From these remarks and behaviours, his parents began to think that Takeharu was talking about the battleship Yamato. Since he repeatedly told them that he wanted to see Yamato, they took him to the Yamato Museum, which is located where the battleship Yamato was completed and has exhibitions related to the battleship including a 1/10 scale model of Yamato (26.3 meters long) displayed in the lobby. When Takeharu saw the display, contrary to his parents’ expectation that he would be delighted to see such a big display, he became upset and cried, saying: ‘It’s not Yamato! It’s a fake! It’s much bigger!’
From his remarks and knowledge, the past-life personality Takeharu remembered appeared to be one of the youngest graduates of the Naval Academy. Eight of them died on the day of the battle in which Yamato was sunk, five were on Yamato and three were on other battleships. When Takeharu was shown the pictures of the eight, he pointed out one of the five and said that he was this person. Because of the lack of necessary information, this statement is not yet verified, but he also pointed out one picture and said that the person on the picture was his best friend who was on the cruiser Yahagi. The person was indeed on Yahagi and was killed when it was attacked and sunk. This appears to suggest that the person Takeharu recalled was the person in the picture he picked up.16
Unsolved Japanese Cases
This is an unsolved international case. Akane, who was born in July 2006, had an oval birthmark on her forehead, appearing just like a bindi. She appeared to be attracted by dark-skinned people such as Indians or Nepalese she met at a restaurant, which perplexed her mother. When her mother wore a towel on her head after a bath, she got upset, claiming: ‘Women should not do that.’ At three years, she started talking about her past life as an Indian girl who died young because of the fire caused by a man wearing glasses who illicitly fell in love with her mother. She recalled her name, and other family members' names, which the consulted Indians all judged sounded likely Indian names. She showed some symptoms of arson phobia which seemed to be attributed to the violent death she claimed to have suffered in her past life. She knew some Indian gods, who are unfamiliar to most Japanese. As for the birthmark, she said that it was marked by a goddess she met after she died in the fire so that she would not forget her life in India.17
Aya was born in February 2002 in the Kanto region. When she was five, she started talking about her past life memories as a female child of a restaurant owner. The restaurant was located possibly in an island in the Kansai region and serving sushi and fish. Although Aya was born and raised in an inland area, she had unusually detailed knowledge about fish and marine products. She also spoke some dialectal expressions of the Kansai region, and knew the difference between the form of sushi in fried tofu (called ‘inari zushi’) in the Kansai region and that in the Kanto region, of which her parents had no knowledge. She had vivid memories of a big earthquake but she was not certain whether her past-life personality died because of the earthquake. The person she talked about has not been identified and the case remains unsolved.18
Mu, a female child who was born in July 2008, was a very stubborn and difficult child to raise. When she was aged three years, in a car driven by her mother, she suddenly talked about her past-life memories: ‘The former me fell, hit the head on the ground, and went to the heaven. I didn’t know where to go, fell, hit the head, and the head became a mess, and I peed.’ Surprised, all her mother could say was: ‘Were you big at that time?’ To the question, Mu said: ‘I wouldn’t have fallen if I had been big.’ Then, for a while, Mu talked about her past-life memories such as she had been a male, she had gotten on an aeroplane with her (his) father, and she did not have a mother. She recalled the name of the person in her past life, but gave no detailed information which would have allowed for further investigations.19
This is an unusual case in that phobias and other anxieties apparently related to past-life memories were alleviated by the child's recalling and talking about them, just like past-life recalls under a past-life hypnotic regression therapy tend to help alleviating problematic symptoms. Koko was born in September 2001. Ever since she was born, she had had strong sense of fear, anxiety, and guilt (which she later recalled were due to her past-life memories) and had hard time going to school or playing with other kids.
In 2014, when she was twelve, Koko had a chance to watch a movie dealing with children with prenatal memories.20 As she watched the children in the movie talking about their past-life memories, she realized that what she had were past-life memories and that not everybody had such memories so that people without them, including her mother, were unable to understand how she had been feeling. On that day, she confessed to her mother what had been tormenting her, her past-life memories. Once she started talking, words gushed out of her mouth, which described at least as many as twenty past lives, which her astounded mother recorded shortly after the confession. Most of the memories were unverifiable, but there were some factually correct pieces of information which Koko was unlikely to have. For instance, when she recalled a past life as an Indonesian musician, she said she had played the Gamelan, an Indonesian musical instrument. After this incident, Koko's mental conditions were greatly alleviated and she became able to go to school.21
This case was investigated by Ohkado along with Ikegawa Akira and interviews with the child and his mother were filmed in a documentary focusing on children's prenatal memories.22
Noriya was born in March 2003. When he was three, he began to act hysterically when he saw buttons on clothes. He even refused to wear clothes with buttons. Gradually he explained: ‘When I was a baby, I was slapped and kicked by a person wearing clothes with buttons. The colour of the clothes was green, with blue, white, red, and yellow.’ When asked where his parents had been, he replied that they had been in ‘shuyoukan’, which can be interpreted as a concentration camp. He also recalled that he himself was brought to a place which was surrounded by barbed wire fences and that he saw a peculiar flag.23 His memories and traumatic reactions subsided after his mother consulted and followed the advice of a psychic, who explained that the story Tomoya was talking about was his past-life memories and suggested that she understand the traumatic experiences Tomoya had suffered.24
This is an unsolved international case in which Tomo, who was born in January 2000, had past-life memories of a child living in Edinburgh, Scotland. He was attracted to and mastered writing in Roman letters before he began to write in the Japanese letters. He was able to sing along the English song ‘Top of the World’ when he first heard it on TV. When he was three years old, he started talking about past-life memories, claiming that he was a boy of a restaurant owner in Edinburgh who died in 1997 at the age of nine due to health problems. He gave detailed information about his life in Great Britain including the dates of his birth and death (but not his full name), and showed strong desire to go back to Edinburgh to meet his former mother. Since he repeatedly asked his parents to take him to Edinburgh, his father eventually agreed to do so when Tomo was seven years old. Although the trip was not successful in the sense that they could not find the person and the restaurant they were looking for, it seems to have soothed Tomo’s desire to go back to his former house and the memories faded.25
This is another unsolved international case, in which a child appeared to have memories of a victim of the September 11 attacks on the World Trade Center in 2001. Yu was born in July 2014. He was a nervous child and whenever he was taken to a new place, he obsessively looked for a fire alarm and a security camera. He was abnormally scared of the sound of a fire alarm or similar sounds. When he was three, as he was walking with his mother, he found a threshing machine. He said: ‘I know how to use it. In the life before the last, I was a rice dealer.’ His mother asked: ‘Then who were you in the last life? I’m wondering why you keep on looking for a fire alarm.’ Then he said: ‘There were two tall buildings. I was working there, using computers. I spoke English. There was a fire or something. Fire alarms were ringing. I was trying to run away. There were fire engines coming to the other building. There seemed to have been a huge accident. Firefighters were coming but they couldn’t come in time. I tried to run away, but there was a big “bang,” and I died.’ ‘That must have been scary, but what floor were you on?’ asked the mother, to which Yu replied: ‘On the 100th floor.’
If Yu’s memories were correct, probably he was in the World Trade Center's South Tower, which was hit after the North Tower was hit. The 100th floor of the South Tower was occupied by Aon. So he might have been one of the 176 workers of the company. However, when Ohkado showed some pictures of the workers available on the web, Yu did not recognize any of them.26
Yumeri was born in October 2005. Unlike other members of the family, she was unusually pious (although she did not stick to any particular religious traditions) and regularly talked about gods and Buddha. When Yumeri, who was six years old, was lying on the floor of their house, her mother, who was also lying with Yumeri, started to sing a Japanese version of ‘My Grandfather’s Clock’. The song appeared to trigger Yumeri to recall her past-life memories. She burst into tears and wailed: ‘My mother died on Tuesday. My father became so sad that he lost memories. He was so sad that he went into hospital, and cried and died. I was singing the song when I was young [in the past life].’
After that incident, she kept on wailing: ‘I want to see my mother.’ All Yumeri's mother could do was just hug her tightly and console her saying: ‘I know how you feel. You do want to meet your mother.’ This lasted for about two weeks. Then, one day when Yumeri's mother was consoling her as usual, she began to stare at her mother’s eyes, and cried: ‘You ARE the mother!’ She seemed to have realized that the present mother was the same person (or the same spirit) as the mother in her past life. After that, she made some remarks about her past life such as: ‘I’m happy to have a nice piano teacher now. My former teacher was really mean, and very easily upset.’27
Harada, T., & Mitsugu, T. (1967). Nihon Ryoiki (in Japanese). Tokyo: Heibonsha.
Hirata, A. (2000). Senkyo Ibun/Katsugoro Saisei Kibun. (Edited and annotated by N. Koyasu). Tokyo: Iwanami.
Iida, F. (2015). Kanzenban ikigai no souzou (Creating the value of life, ultimate edition). Tokoyo: PHP Shuppan.
Ikegawa. A. (2014). Zensei wo kiokusuru Nihon no kodomotachi (Japanese children remembering past lives). Tokyo: Soleil.
Ikegawa A., & Kiwako (2014). Anone mama wo puresento-shitette onegai-shitanda (You know, I asked god to present mom to me). Tokyo: Zennichi Publishing.
Ikegawa, A., & Ohkado, M. (2005). Hito wa umarekawareru (People can be reborn). Tokyo: Popularsha.
Matsutani, M. (2003). Gendai-minwakou, 5 – Shi no shirase, Anoyo e itta hanashi (A study of modern folklore, 5 – News of death, stories of going to the other world). Tokyo: Chikuma Shobo.
Nakamura, H., & Hayashima, K. (2007). Shomankyo Gisho, Yuimakyo Gisho (in Japanese). Tokyo: Iwanami Shoten.
Ogikubo, N. (Director) (2016). Kamisama tono yakusoku (Prenatal memories of children) [Film]. Tokyo: Kumanekodo.
Ohkado, M. (2012). "Kakoseikioku" wo motsu kodomo – Indojin toshiteno kioku wo motsu nihonjin-joji no jirei (Children with "past-life memories" – A case of a Japanese female child with "memories" as an Indian). Journal of Mind-Body Science 21/1, 17-25.
Ohkado, M. (2013). A case of a Japanese child with past-life memories. Journal of Scientific Exploration 27/4, 625-36.
Ohkado, M. (2016a). A same-family case of the reincarnation type in Japan. Journal of Scientific Exploration 30/4, 524-36.
Ohkado, M. (2016b). Kakosei-taikousaimin-ryouhou niyoru shoujou-keigen-kouka to ruiji-shita tokuchou wo shimesu sizen-hassei-saiseigata-jirei (A spontaneous case of the reincarnation type showing characteristics similar to the therapeutic effects observed in past-life regression therapy). Journal of the Faculty of General Education, Chubu University, 2, 9-21.
Ohkado, M. (2017a). Same-family cases of the reincarnation type in Japan. Journal of Scientific Exploration 31/4, 551-71.
Ohkado, M. (2017b). Tanjoumae-, tanjouji-kioku wo kataru kodomotachi—Nihon ni okeru mittsu no jirei (Children with pre- and perinatal memories—Three Japanese cases). Journal of the Faculty of General Education, Chubu University 3, 13-27.
Ohkado, M. (2020). Chuzetsu no kankeisuru saiseigata-jirei (A case of the reincarnation type involving abortion). Chubu University Journal of Liberal Arts 2, 14-30.
Ohkado, M. (2021). "Umarekawari" wo kagakusuru (Scientifically investigating "reincarnation"). Tokyo: Sakuranohana Press.
Takekura, F. (2015). Rinne Tensei: <Watashi> wo Tsunagu Umarekawari no Monogatari (Reincarnation: The story of rebirth connecting "I." Tokyo: Kodansha.
Tucker, J B. (2005). Life Before Life: Children's Memories of Previous Lives. New York: St. Martin’s Press.
Yamada, Y. (1994). Jomon Jidai no Kodomo no Maiso (Mortuary practices for children in Jomon Japan: An approach to Jomon life history). Nihon Kokogaku (Journal of the Japanese Archaeological Association) 4/4, 1-39.
- 1. Yamada (1994);Takekura (2021).
- 2. Takekura (2021).
- 3. Nakashima & Hayashima (2007).
- 4. Harada &Takahashi (1967).
- 5. Matsutani (2003).
- 6. Ikegawa & Kiwako (2014); Iida (2015). The number will be multiplied if cases of adults who claim to have past-life memories since they were children or those who claim to have recalled such memories after they became adults (Ikegawa (2014)).
- 7. An American case involving abortion was reported by Tucker (2005, 114-16).
- 8. Ohkado (2020).
- 9. Ohkado (2017a).
- 10. Ohkado (2016a).
- 11. Ohkado (2017a).
- 12. Ohkado (2017a).
- 13. Ohkado (2017a).
- 14. Hirata (2000).
- 15. Ohkado (2021).
- 16. Ohkado, 2021).
- 17. Ohkado (2012).
- 18. Ikegawa & Ohkado (2015).
- 19. Ohkado (2017b).
- 20. Ogikubo (2013).
- 21. Ohkado (2016b).
- 22. Ogikubo (2016).
- 23. The flag has not been identified. Historians working on the German Nazi period Ohkado consulted did not recognize the flag drawn by Noriya.
- 24. Ogikubo (2016).
- 25. Ohkado (2013).
- 26. Ohkado (2021).
- 27. Ohkado (2017b).