Naturalisation: 10 years' residence now expected, with longer tax checks

The Justice Minister announced the change on 27 March 2026. The Nationality Act still sets a 5-year address condition, and the minister said applicants must meet that first. On top of it:

• Residence: to show you’re integrated into Japanese society, you’re expected in principle to have lived in Japan for 10 years or more.
• Tax: Tokyo’s Legal Affairs Bureau asks for 5 years of resident tax certificates, plus proof you paid resident tax on time for 5 years unless it’s deducted from your salary. If you file tax returns, it also asks for 3 years of income tax certificates.
• Social insurance: the Tokyo and Kofu bureaus ask for 2 years of pension and health insurance payment records.

Kyodo reports that both checks previously went back 1 year. These are the documents the bureaus ask for, and they can also cover your spouse and people you share a household with. A bureau may ask for different papers in your case, so check its current list before you collect anything.

The government says it’s still looking at tightening naturalisation further, including whether applicants can support themselves in the long term.

Not clear yet

• Applications filed before 1 April 2026: Kyodo reported the new approach covers them, and Nikkei says it applies to decisions made from that date. The official texts we’ve read don’t say.
• Spouses of Japanese nationals and others on the relaxed routes: the Nationality Act eases some conditions for them, and the Ministry’s Q&A still says so. Nothing official says how the 10-year standard treats them. One gyoseishoshi firm says they don’t necessarily need 10 years, but ask your Legal Affairs Bureau.