# Japan National Holiday Working Day

> Checks a date against Japan's statutory national holidays and Saturday/Sunday baseline.

- Calculator id: `japan-national-working-day` · Category: Everyday Life (`everyday`) · Tool name: `check_japan_national_working_day`
- Canonical page: https://tttkmbb.com/everyday/japan-national-working-day · This document: https://tttkmbb.com/everyday/japan-national-working-day.md · JSON definition: https://tttkmbb.com/everyday/japan-national-working-day.json

## Purpose

Checks a date against Japan's statutory national holidays and Saturday/Sunday baseline.

**Use when:** You need Japan statutory national-holiday status for 2026-2027.

**Do not use when:** You need a company, school, bank, exchange or prefectural closure calendar.

## Example user requests

- Is 2027-03-22 a Japan working day?


## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `date` | date |  | required | Gregorian date in the pinned Cabinet Office 2026-2027 coverage. |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `territory` | string |  | JP. |
| `territory_name` | string |  | Japan. |
| `weekday` | string |  | Gregorian weekday. |
| `is_working_day` | boolean |  | True when the Japan Saturday/Sunday baseline is a weekday and no statutory national holiday applies. |
| `day_type` | string |  | Regular weekday, regular weekend or statutory national holiday. |
| `holiday_names` | string_list |  | Japanese statutory holiday names applying on the date. |
| `holiday_kinds` | string_list |  | National holiday or statutory holiday under the Cabinet Office table. |
| `holiday_legal_bases` | string_list |  | Holiday Act or Cabinet Office legal classification. |
| `weekend_days` | string_list |  | CLDR Saturday/Sunday baseline. |
| `calendar_scope` | string |  | Japan statutory national holidays only. |
| `rest_day_policy` | string |  | Company, school, bank and exchange closures are not inferred. |
| `calendar_profile` | string |  | jp-cabinet-office-national-holidays. |
| `dataset_version` | string |  | Pinned Cabinet Office evidence package. |
| `sources` | list |  | Official Cabinet Office and legislation sources. |

## Formula

`is_working_day = Japan weekday baseline and no Cabinet Office statutory holiday`

Apply the pinned Cabinet Office national-holiday table on top of the CLDR Japan weekend baseline.

## Data Sources

- Cabinet Office of Japan - National Holidays — https://www8.cao.go.jp/chosei/shukujitsu/gaiyou.html (government, published 2026-09-29)
- Act on National Holidays (Act No. 178 of 1948) — https://laws.e-gov.go.jp/law/323AC0000000178 (legislation)

Data freshness: `static`. The Cabinet Office publishes the national-holiday table; refresh only after official review.

## API

- `GET https://tttkmbb.com/api/v1/calculate/japan-national-working-day?date=…`
- `POST https://tttkmbb.com/api/v1/calculate/japan-national-working-day` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/japan-national-working-day · OpenAPI operationId `check_japan_national_working_day` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool: `check_japan_national_working_day` (dedicated) or `run_calculator` with `{"calculator_id": "japan-national-working-day", "inputs": {…}}`

## Example

- Article 3(2) statutory holiday: inputs `{"date":"2027-03-22"}` → `{"is_working_day":false,"holiday_kinds":["statutory_holiday"]}`

```
GET https://tttkmbb.com/api/v1/calculate/japan-national-working-day?date=2027-03-22
```

## Limitations

You need a company, school, bank, exchange or prefectural closure calendar. Apply the pinned Cabinet Office national-holiday table on top of the CLDR Japan weekend baseline. All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Does this cover Japanese company holidays?**

No. It is limited to statutory national holidays and the Japan Saturday/Sunday baseline.

## Related

- [Add Japan National Working Days](https://tttkmbb.com/everyday/japan-national-add-working-days.md) — Offset using the same statutory national-holiday evidence package.