of Japanese nationality by birth under article 2(i) cannot be confirmed retroactively just because a child was recognized by a Japanese male (father) after birth.170 As stated above, A had been treated as having had acquired Japanese nationality under Article 2(i) of the Nationality Act by birth with his legal father being D. This was because A’s mother (who was of ROK nationality at the time of delivery) was legally married to D (a Japanese national) at the time of A’s birth and the presumption of legitimacy had once been effective for some time.171 However, 30 years later, the court decision denying the father-child relationship between A and D had been made and finalized. The fact that A did not have a legal father at the time of birth was confirmed. It is noted that A was recognized after birth by C (a Japanese national); however, as stated above, the current interpretation of the law is that recognition of parentage cannot have retroactive effect so as to enable the acquisition of Japanese nationality by birth under Article 2(i). A thus could not acquire Japanese nationality based on his established legal descent from C.172 As a result, A was subjected to quite severe treatment by being considered to have retroactively lost his Japanese nationality at the time of his birth and being processed as an illegally staying foreigner as stated above. b) ROK B, the mother who gave birth to A, was of ROK nationality at the time of delivery. ROK’s nationality law before the amendment coming into force on 14 June 1998 adopted the paternal jus soli principle, as with Article 2(i) of the pre-amendment Japanese Nationality Law. One did not acquire ROK nationality just because he or she was born to a mother of ROK nationality. Thus, A did not acquire ROK nationality by birth under the law of ROK.173 In practice also, even if A—who had been living as a Japanese national for more than 30 years—suddenly claimed that he “has been of ROK nationality retroactively since the 170 See supra note 168; Supreme Court judgment, 22 November 2002. On presumption of birth in wedlock and its denial, see note 180 below. 172 By the 2008 amendment of the Nationality Act Article 3 (i), it became possible for a child who has been recognized by a Japanese father before the age of 20 to acquire Japanese nationality even if the parents are not married. However, A in Case 9 would not have been saved even after the amendment because A was already in his 30s at the time of recognition by C. 173 According to Article 2 (iii) of the Korean Nationality Act effective at the time of A’s birth, “when the father is unknown… a person whose mother is a national of the Republic of Korea” acquires Korean nationality. However, A, at the time of birth, had a legal father who was a Japanese national, although this legal father-child relationship was later denied, A was recognized by C, who is the natural father, and therefore already has a legal father. Based on the fact that recognition of a child has a retroactive effect under the Japanese Civil Code, A would have had a legal father-child relationship with C since the time of birth. Also, A’s mother naturalized in Japan shortly after A’s birth and no longer has Korean nationality. Under such circumstances and after more than 30 years had passed, there would have been very little possibility that A would have been treated as having had acquired Korean nationality at birth based on Article 2 (iii) of the Korean Nationality Act. 171 81