Japanの税務居住ルール：183日テスト
183日のしきい値
Japanにおける183日ルールの仕組み
Japan treats anyone with a domicile or 1+ year of residence as a tax resident. The 183 day rule applies mainly to treaty contexts.
暦年（1月〜12月）. これは、日数カウントが毎年1月1日にリセットされることを意味します。前年の日数は繰り越されません。
183日を超えると、Japanは税務居住者としてあなたの全世界所得に課税する可能性があります。具体的な影響は、個人の状況、適用される租税条約、所得の種類によって異なります。
日数のカウント方法
Japan does not lean on a 183 day rule for domestic residency. Instead, you are a resident (a "kyojusha") if you have a "jusho", which is your domicile or the base of your living, in Japan. Failing that, you become resident if you maintain a "kyoshou", a place of abode, in Japan continuously for one year or more. Domicile is presumed where the centre of your life is.
1日とみなされる条件
The one year test looks for continuous residence. Short trips abroad usually do not break the chain, but a substantial absence with no Japanese base behind you can reset the count.
日数以外の判定基準
Inside Japanese tax residency there is a further split that matters for foreign income. You are a permanent resident if you are a Japanese national, or a non Japanese person who has had a domicile or aggregate residence in Japan exceeding 5 of the past 10 years. Otherwise you are a non permanent resident, taxed on Japanese source income and on foreign income only when it is paid in or remitted to Japan.
特別税制
Japan does not run a formal expat regime, but the non permanent resident status effectively functions as one. For the first five years of Japanese residency, many newcomers shelter their foreign source income from Japanese tax by simply not remitting it.
租税条約
Japanese treaties broadly follow the OECD model. The 183 day rule does appear, but in the employment income article, where it splits taxing rights between Japan and a worker's home country.
よくある質問
Is there a 183 day rule for Japanese tax residency?
Not under domestic law. Japan looks at domicile and continuous one year residence instead. The 183 day rule shows up in tax treaties, where it allocates taxing rights for short term assignees between Japan and their home country.
How does non permanent resident status help?
A non Japanese person with Japanese tax residency for five or fewer of the past ten years pays Japanese tax only on Japanese source income, plus any foreign income that is actually paid into or remitted to Japan. Foreign income kept outside Japan is generally not taxed at all.
Does buying a home in Japan create residency?
It is a strong factor in establishing domicile, but not enough on its own. The NTA looks at the wider picture: where your family is, where your work happens, where your social life sits, and so on.
公式情報源: https://www.nta.go.jp/english/index.htm