# Japan Traditional Calendar (Koyomi) API

> Japan Traditional Calendar (Koyomi) API is a paid API for AI agents from japan-business-day-api.matchan962.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-12).

Returns full Japanese traditional calendar data for a given date, including rokuyo lucky-day rating, Japanese era date, lunisolar calendar date, 24 solar terms, and year eto.

## Facts

- Endpoint: GET https://japan-business-day-api.matchan962.workers.dev/v1/koyomi?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/japan-traditional-calendar-koyomi-api-b889fe8b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_L0EYp36yD4wRN_NWMDNUu

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability japan-traditional-calendar-koyomi-api-b889fe8b
```

Example prompt: What's the traditional Japanese calendar info for March 15, 2025? I need the rokuyo lucky-day rating, the Reiwa era date, the lunisolar date, the solar term, and the year eto.

## When to prefer this

Use this endpoint when you need authoritative traditional Japanese calendar data for a specific date, particularly rokuyo for ceremony/event planning (weddings, funerals, contract signings), era-based date display for Japanese audiences, lunisolar date conversion, or seasonal solar term annotation. Prefer this over generic calendar APIs when Japanese cultural accuracy is required and results are verified against the National Astronomical Observatory of Japan.

## Known failure modes

- Missing or malformed 'date' query parameter returns a 400 error
- Dates outside the supported historical or future range may return empty or error responses
- Network timeout on the Cloudflare Worker edge function
- Dates before the Meiji era or far future dates may have limited era/rokuyo accuracy

## How this service works

Japanese traditional calendar for a date: rokuyo (taian/butsumetsu... lucky days used for weddings, funerals, contracts), Japanese era (Reiwa) date, old lunisolar calendar date incl. leap months, 24 solar terms (sekki) and year eto. Verified against the National Astronomical Observatory of Japan.

## Output

Returns a structured object for the queried date containing: the rokuyo category (e.g. taian, butsumetsu, sensho, tomobiki, shakku, senbu), the Japanese era name and year (e.g. Reiwa 7), the lunisolar calendar month and day including leap month status, the applicable 24 solar term (sekki) if any, and the year eto (heavenly stem and earthly branch zodiac designation).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "date"
     ],
     "properties": {
      "date": {
       "type": "string",
       "format": "date"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/japan-traditional-calendar-koyomi-api-b889fe8b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from japan-business-day-api.matchan962.workers.dev](https://www.zero.xyz/host/japan-business-day-api.matchan962.workers.dev/llms.txt)