Choice-of-nationality failure → ministerial demand → loss

Example scenarios

• Sophie became dual before 18 (she was dual from birth — born 2006). Under Art. 14 (Act 59/2018, EIF 2022-04-01): because she became dual before reaching 18, she must choose a nationality by the time she reaches 20 (i.e., by 2026). She turned 18 in 2024, so she has until 2026. She cannot formally keep both — Japanese law requires choosing one. She can choose Japanese nationality by: (a) renouncing French nationality, or (b) making a selection declaration under Art. 14(2). The selection declaration creates only an endeavor duty to renounce French nationality (Art. 16(1)), not an absolute requirement — this is the practical path that allows de facto retention. If she fails to choose by 2026, she is in default under Art. 14. However, the Art. 15 demand (催告) has never been issued in practice, so many Japanese-French dual nationals remain in an unenforced dual-nationality position. Formal advice: make the selection declaration promptly.

  Became dual before 18 (at birth) → must choose by reaching 20 (by 2026) | Choice: renounce French nationality OR make selection declaration | Selection declaration = endeavor duty only (Art. 16(1)), not mandatory renunciation | Art. 15 demand never issued — de facto tolerance but legally precarious

• If Kenta registers as an American citizen at the U.S. consulate at age 18, the key question under Japanese law is whether this is a 'voluntary' acquisition of foreign nationality under Art. 11(1) or an automatic acquisition regulated by Art. 14. Under Japanese law: acquiring a foreign nationality 'at birth' by operation of law is what is governed by Art. 14 (choice obligation). However, if he is 18 at the time of registration and the act of registering is the voluntary election that creates U.S. citizenship (not an automatic acquisition at birth that he is merely documenting), Art. 11(1) might apply. The line between 'registration of automatic jus sanguinis' and 'voluntary application for nationality' is legally gray in Japanese jurisprudence. If Art. 11(1) applies: he automatically loses Japanese nationality at the moment of U.S. citizenship acquisition. If Art. 14 applies (automatic by birth descent, confirmed at any time): he would be a dual national subject to the Art. 14 choice obligation. This is an NLR-LOW unresolved question on these specific facts.

  Key question: is post-birth consular registration of descent-based U.S. citizenship 'voluntary acquisition' (Art. 11(1)) or confirmation of automatic birth acquisition (Art. 14)? | Art. 11(1): voluntary acquisition fires Art. 11(1) loss | Art. 14: automatic acquisition at birth is subject to choice obligation, not Art. 11(1)

• Using an American passport in the United States (or internationally) does NOT, by itself, cause loss of Japanese nationality. Art. 11(1) fires only on VOLUNTARY ACQUISITION of a new foreign nationality — Mei already held U.S. citizenship from birth; she is not acquiring it. Art. 16(2) deprivation applies only if she assumes a foreign PUBLIC OFFICE contrary to the purport of her selection declaration. Living in the U.S. and using her U.S. passport for travel are private acts that do not trigger Art. 16(2). The Art. 16(1) endeavor duty (to renounce U.S. citizenship after making the selection declaration) creates a soft obligation — breach of this duty alone does not cause nationality loss; it must be paired with the specific Art. 16(2) foreign-public-office scenario. Mei remains a Japanese national. Her Japanese nationality is secure for ordinary private life in the U.S.

  Using a foreign passport does not trigger Art. 11(1) — she already held U.S. citizenship | Living abroad does not affect Japanese nationality | Art. 16(2): applies only on assumption of foreign public office (private life in U.S. = not applicable) | Art. 16(1) endeavor duty: soft obligation, not loss trigger on its own

• To choose Japanese nationality under Art. 14(2), Kimi has two options: (A) Renounce U.S. citizenship: apply to the U.S. government (through U.S. Embassy) for renunciation of U.S. citizenship under U.S. law — a formal, irrevocable process; then record the renunciation in the Japanese koseki. (B) Make a selection declaration (選択の宣言) under Art. 14(2): file a written selection declaration at a Legal Affairs Bureau or Japanese consulate/embassy, declaring the choice of Japanese nationality. The declaration creates only an endeavor duty to renounce U.S. citizenship (Art. 16(1)) — not a binding obligation. The declaration is recorded in the koseki. Option B is the far more common and practical choice — it does not require immediate renunciation of U.S. citizenship and is relatively straightforward. Procedure for Option B: (1) visit a Legal Affairs Bureau or consulate; (2) complete the selection declaration form; (3) the bureau records the declaration in the koseki; (4) Kimi endeavors (but is not legally compelled) to renounce U.S. citizenship afterwards. No statutory filing fee for the declaration.

  Art. 14(2): two methods to choose Japanese nationality — renounce foreign nationality OR make selection declaration | Selection declaration is the practical path — creates only endeavor duty (Art. 16(1)) | Filed at Legal Affairs Bureau or consulate | Deadline: before she turns 20 (Art. 14 rule for those who became dual before 18)

• Kyoko's applicable rule is the OLD pre-2022 Art. 14 deadline (by age 22 if dual before 20). The Act 59/2018 transitional provisions state that persons who were 20+ at EIF (2022-04-01) retain the OLD rule. Kyoko was 32 at EIF — clearly over 20. Under the OLD rule: she became dual before age 20 (she was dual from birth in 1989), so the deadline was by reaching 22 (i.e., by 2011). She is now 36 — 25 years past the OLD deadline. She is in chronic default under Art. 14. However, the Art. 15 demand (催告) has NEVER been issued in practice (despite decades of accumulated defaults). She remains a Japanese national in a de facto tolerated position. She should make a selection declaration to regularize her status. The stale EN translation's '22' framing is the CORRECT value for her (she is in the old-rule cohort).

  OLD rule applies to Kyoko (over 20 at EIF 2022-04-01) | OLD rule: dual before 20 → choose by 22 (deadline: 2011) | She is 36 — 25 years past OLD deadline | Art. 15 demand never issued — de facto tolerance but legally precarious