# Japan Business Tools Muse connector

From musedirectory.ai, the independent directory of Meta Muse connectors. Not affiliated with Meta.

## Japan Business Tools

Check Japanese holidays, business days, and calculate deadlines accounting for weekends and closures.

- Record: https://musedirectory.ai/connector/japan-business-tools
- Category: Productivity
- Developer: ossalt.jp
- Muse status: Extra setup. Not in Muse's Connectors list yet. Muse can still use it: its page gives you a request to paste into Muse.
- Health: Working, 72ms, checked 2026-10-29T12:15:52Z
- Endpoint: https://biz.ossalt.jp/mcp
- Auth: No account needed; Pricing: unknown
- Screening: Screened, no issues found (2026-10-28T22:31:38Z)
- Source: Found in the official MCP Registry (jp.ossalt/jp-biz-tools) https://registry.modelcontextprotocol.io/v0/servers?search=jp.ossalt%2Fjp-biz-tools

Provides Japanese national holidays, business day calculations, and date adjustments for Japan. Helps determine if a date is a business day, count working days between dates, and shift deadlines to the next or previous business day.

Example request: "Tell me the last business day of this month in Japan so I know when to schedule a payment."

How to connect: Not in Muse's Connectors list yet, but Muse can still use it. Paste this into Muse: "Use Japan Business Tools to help me. It is a free service with an MCP server at https://biz.ossalt.jp/mcp. It does not need an API key. Ask me before you share anything with it." Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.

Tools:
- list_holidays: List all Japanese national holidays and substitute holidays for a year, based on the National Holidays Act and verified against the Cabinet Office CSV. Each holiday has `name` (descriptive) and `official_name` (as written by the Cabinet Office). / その年の国民の祝日・休日（振替休日・国民の休日を含む）の一覧。n
- check_business_day: Check whether a date is a business day in Japan, and if not, why (weekend, holiday name, bank closure, or a custom closed day). `reason` is Japanese text; `reason_code` is one of weekend, holiday, bank_closure, extra_holiday (null on business days). flags: `estimated`/`unverified
- add_business_days: Return the date that is N business days after (or before, if N is negative) the given date. The start date itself is not counted; e.g. 1 business day after a Friday is the next Monday unless it is a holiday. / n営業日後（nが負なら前）の日付。起算日は数えない。
- count_business_days: Count business days from start to end, inclusive of both ends. Returns 0 if start is after end. The period can be up to 3,660 days (about 10 years). / start から end までの営業日の数（両端を含む）。start が end より後なら 0。期間は3,660日（約10年）まで。
- adjust_to_business_day: If the date is a business day, return it as is; otherwise move to the next ("next") or previous ("previous") business day. Useful for payment due dates that fall on holidays. / 営業日ならその日、休みなら次（next）または前（previous）の営業日。支払日が休みのときなどに使う。
- last_business_day_of_month: Return the last business day of the given month. / その月の最終営業日。
- to_japanese_era: Convert a Gregorian date (YYYY-MM-DD) to the Japanese era calendar, e.g. 2026-10-07 → 令和8年10月7日 (wareki_short R8.10.07, zero-padded). Year 1 is written 元年. Supported from 1873-01-01 (the Gregorian calendar was adopted on 明治6年1月1日). Eras: 令和 (R) from 2019-05-01, 平成 (H) from 1989-0
- from_japanese_era: Convert a Japanese era date to YYYY-MM-DD. Accepts 令和8年10月7日, 令和元年5月1日, R8.10.7, H31/4/30, Reiwa 8.10.7, kanji numerals (昭和六十四年一月七日), a trailing weekday such as （水） or 水曜日, and full-width characters. `input_era`/`input_era_year` echo the input; `actual` is the correct era for tha
- lookup_postal_code: Look up the address (prefecture, city, town) for a 7-digit Japanese postal code, from Japan Post data. Accepts forms like 1000001, 100-0001 or 〒100-0001. One code can cover several towns; all are returned. `town_detail` holds the parenthesized part as written by Japan Post (e.g. 
- search_postal_code: Find Japanese postal codes by prefecture, city and (optionally) part of the town name, from Japan Post data. The city must be the full municipality name (e.g. 札幌市中央区, 新宿区); the county name may be omitted. With `office_name`, searches business-specific codes (大口事業所個別番号) of busines
- normalize_address: Split a Japanese address into prefecture, city, town and the rest (block numbers, building), matching Japan Post's address data, and return candidate postal codes. Absorbs full/half-width, spacing, kanji vs. arabic numerals, ヶ/ケ and omitted county names; fills in the prefecture w
- lookup_corporate_number: Look up a 13-digit Japanese corporate number (法人番号) in the National Tax Agency's monthly bulk data: name, furigana, English name, kind, registered address and postal code, assignment date, and closure (date, cause, successor) if the registry record was closed. The check digit (fi
- search_corporation_by_name: Find Japanese corporations whose name starts with the given text (prefix match), in the National Tax Agency's monthly bulk data. Legal-form words such as 株式会社 or 一般社団法人 are ignored at either end, and full/half-width and spaces are normalized. Matching in the middle of a name and 

Screening checks:
- MCP handshake: pass (Answered in 44ms)
- Domain against threat feeds (Cloudflare security DNS): pass (biz.ossalt.jp not flagged)
- Published packages against the OSV malicious-package database: n/a (No npm or PyPI package published)
- Hidden instructions or invisible characters in tool text: pass (6 tools read, nothing found)
- Inputs asking for passwords, card numbers or seed phrases: pass (None found)
- Domain and redirects: pass (No redirects off the domain)
- AI review of purpose and tool behavior: pass (No concerns)