Ciudadanía por descendencia (jus sanguinis)

Escenarios de ejemplo

Los escenarios de ejemplo se muestran en inglés.

• Hana acquired Japanese nationality automatically at birth under Art. 2(i) (either-parent jus sanguinis, EIF 1985-01-01). Because the reservation was properly filed within 3 months (Art. 12 + Family Register Act Art. 104), retroactive loss under Art. 12 did not trigger. She holds dual nationality today. Under Art. 14 (as amended by Act 59/2018, EIF 2022-04-01): she became dual before reaching 18, so the deadline was to choose by reaching 20. She is now 29 — past the deadline. She has not made a choice declaration. Technically she is in default under Art. 14, but the Art. 15 ministerial demand (催告) has NEVER been issued in practice (despite ~925,000 duals as of 2018), so no actual loss has occurred. She remains a Japanese national in a legally ambiguous but practically tolerated dual-nationality position. She should make a selection declaration promptly to regularize her status.

  Father Japanese at time of birth (Art. 2(i)) | Either-parent rule operative since 1985-01-01 | Reservation filed within 3 months (Art. 104) | Art. 12 retroactive loss averted | Art. 14 deadline passed but demand never issued

• Yui acquired Japanese nationality at birth under Art. 2(i) (father Japanese at birth). The reservation was filed on time, so Art. 12 retroactive loss was averted. She currently holds valid dual nationality. Under Art. 14 (Act 59/2018, EIF 2022-04-01): she became dual before reaching 18 (she became dual at birth), so she must choose a nationality by the time she reaches 20. She has until her 20th birthday (in 2029). She may choose Japanese nationality by (a) renouncing French nationality or (b) making a selection declaration (選択の宣言). The selection declaration is the more common and practical route — it creates only an endeavor duty to renounce the foreign nationality (Art. 16(1)), not an absolute requirement. Since she is under 15, any formal act (if needed before age 15) would be by her statutory agent (Art. 18), but she is 16 so she can act herself.

  Art. 2(i) descent via father; reservation filed timely; Art. 12 loss averted | Art. 14: chose before 18 → deadline is reaching age 20 (i.e., by 2029) | Choice mechanism: renounce French nationality OR make selection declaration | Art. 16(1) endeavor duty — not absolute renunciation requirement

• Ren acquired Japanese nationality at birth via Art. 2(i) (mother Japanese). Art. 12 does NOT apply — Art. 12 concerns persons born ABROAD who acquire a foreign nationality at birth. Ren was born in Japan. The subsequent adoption and French nationality acquisition are relevant: if France conferred French nationality on Ren automatically through the adoption (i.e., by operation of law, not by a voluntary election by Ren himself), then Art. 11(1) does not fire — Art. 11(1) requires voluntary (自己の志望) acquisition. If, however, the French couple or Ren himself applied for French nationality through a process that counts as voluntary, Art. 11(1) would trigger. Under Art. 14: if Ren now holds both Japanese and French nationality and became dual before 18, he must choose by reaching 20. Since he is 8, time remains. Since he is under 15, all formal acts are by his statutory agent (Art. 18).

  Born in Japan to Japanese mother → Art. 2(i) automatic acquisition | Art. 12 inapplicable (born in Japan, not abroad) | Key question: was French nationality acquisition voluntary or by operation of law? | Art. 11(1) triggers only on voluntary acquisition; automatic-by-law acquisition does not trigger it | Art. 14: must choose by age 20 if dual arose before 18

• Carlos does NOT qualify for citizenship by descent. Jus sanguinis under Art. 2(i) transmits through ONE generation only: at least one parent must be a Japanese national at the time of the child's birth. Carlos's father was not Japanese (born in Brazil of a non-Japanese Brazilian father, the sansei grandfather having lost Japanese nationality in the generation gap). There is no grandchild-registration entitlement — the Art. 2 acquisition list is closed. The 4th-generation Nikkei 'yonsei visa' (established 2019) is a LABOUR visa scheme under immigration law, not a nationality route. Carlos would need to pursue ordinary naturalization (JP-NAT-01), which requires 5 years' continuous domicile, among other conditions.

  Jus sanguinis is single-generation (parent must be Japanese at child's birth) | Grandfather's Japanese nationality does not transmit two generations down | Yonsei visa = labour/residence status, NOT nationality | No grandchild descent entitlement in Nationality Act

• Luisa acquired Japanese nationality at birth automatically under Art. 2(i) — her mother was Japanese at the time of birth, and the 1985 either-parent amendment (Act 45/1984, EIF 1985-01-01) permits maternal transmission. However, because she was born OUTSIDE Japan (Peru) and acquired Peruvian nationality at birth, Art. 12 applies. Since no 国籍留保 reservation was filed within 3 months of birth, Luisa retroactively lost Japanese nationality as of the time of her birth. Retroactive loss is confirmed (SC 3rd Petty Bench 2015-03-10, 平成25(行ツ)230). She is not currently a Japanese national. Her best path is reacquisition under Art. 17(1) — BUT only if she is under 18. She is 31, so Art. 17(1) reacquisition is also unavailable. She would need to pursue ordinary naturalization (JP-NAT-01) or, if her mother is still Japanese, the Art. 8(i) child-of-Japanese simplified naturalization (JP-CBN-01) — which requires a Japanese domicile.

  Mother Japanese at time of birth → Art. 2(i) acquisition | Born abroad + acquired Peruvian nationality at birth → Art. 12 applies | No reservation filed within 3 months → retroactive loss from birth | Art. 17(1) reacquisition requires under 18 — age 31 is out of range | Art. 12 constitutionality upheld (SC 2015-03-10)

• David validly holds Japanese nationality under Art. 2(i) (maternal descent; either-parent rule). The Art. 12 loss was averted by the timely reservation. He is currently a foreign-born dual national. Under Art. 14 (post-Act 59/2018): because he became dual before reaching 18, he must choose a nationality by the time he reaches 20. He has until his 20th birthday. He can choose Japanese nationality by either (a) renouncing his U.S. citizenship or (b) making a selection declaration (選択の宣言) under Art. 14(2). The selection declaration is the more common route — it creates only an endeavor duty to renounce the foreign nationality (Art. 16(1)), not an absolute requirement. The demand to actually choose (催告) has never been issued in practice, but the legal obligation runs from his 20th birthday if he has not chosen.

  Art. 12 loss averted by timely reservation | Foreign-born dual → Art. 14 choice deadline by age 20 (since dual arose before 18) | Choice: renounce U.S. citizenship OR make selection declaration | Under-15 rule: statutory agent (mother) acts for him now (Art. 18)