japan-calendar-mcp

by nagarexUpdated May 6, 2026

Supplies five tools for Japanese calendar operations: `is_holiday` checks if a date is a national holiday, `next_business_day` finds the subsequent business day excluding weekends and holidays, `get_holidays` lists holidays for a year, `business_days_between` counts workdays between dates, and `japanese_era` identifies the era like Reiwa or Heisei. Developers integrate it into finance apps for accurate accrual periods, HR systems for payroll, or scheduling tools for Japan-specific deadlines.

japanese-calendar
holidays
business-days
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Overview

The japan-calendar-mcp server exposes five tools tailored to Japanese calendar logic, handling national holidays, business days (excluding Saturdays, Sundays, and holidays), and traditional era names (gengō). It enables programmatic date computations that account for Japan's unique observances, such as Emperor's Birthday or Respect for the Aged Day.

Key Capabilities

  • is_holiday(date): Returns true if the input date is a Japanese national holiday, false otherwise.
  • next_business_day(date): Computes the next valid business day after the given date, skipping non-working days.
  • get_holidays(year): Returns a list of all national holidays in the specified year.
  • business_days_between(start_date, end_date): Counts the number of business days between two dates, inclusive or exclusive based on parameters.
  • japanese_era(date): Identifies the Japanese imperial era for the date, e.g., 'Reiwa 5' for 2023.

Use Cases

  1. Financial Calculations: Use business_days_between to determine precise workdays for interest computations in yen-denominated loans, avoiding holiday distortions.
  2. Project Scheduling: Apply next_business_day to set realistic deadlines in task management apps for Japanese teams.
  3. HR and Payroll: Query get_holidays and is_holiday to adjust employee pay cycles or time-off accruals.
  4. Historical Data Apps: Leverage japanese_era to label dates in timelines or documents for cultural accuracy.

Who This Is For

Developers building applications for Japanese markets, including fintech platforms, enterprise resource planning (ERP) systems, HR software, and content tools requiring era-aware formatting. Data analysts processing time-series data with Japan-specific calendars also benefit.