Description
Add 87 days to verifiedRisshunDate and return inclusiveOrdinal 88.
Some traditional Japanese seasonal dates are counted inclusively from Risshun. The astronomical origin date must be known before a fixed ordinal can be converted to a Gregorian date.
Add 87 days to verifiedRisshunDate and return inclusiveOrdinal 88.
When to use this tool
Use Japanese Hachijuhachiya Date Calculator when you need a fixed traditional ordinal from a verified Risshun date.
How to use the tool and how it works
- Enter verifiedRisshunDate. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read result. Expand result to inspect the returned fields.
Add 87 days to verifiedRisshunDate and return inclusiveOrdinal 88. The supplied origin counts as day one.1
Hachijuhachiya is the 88th day counted from Risshun. Inclusive counting makes its Gregorian offset 87 days from the supplied origin.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| verifiedRisshunDate | Previously verified Gregorian Risshun date, YYYY-MM-DD, in years 0001-9999; output must stay within that year range. | Required. Text. Implementation limit: 8192 Unicode code points and 16384 UTF-16 code units. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| result | Result | Required. Object. |
| result.date | Date | Calculated result member: string. |
| result.inclusiveOrdinal | Inclusive Ordinal | Calculated result member: number. |
{
"input": {
"verifiedRisshunDate": "2024-02-04"
},
"output": {
"result": {
"date": "2024-05-01",
"inclusiveOrdinal": 88
}
}
}Limitations and assumptions
- This uses an explicitly supplied Gregorian Risshun date rather than calculating astronomical timing or regional observance.
- Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Alternative or Complementary methods
Obtain the relevant year's origin from an authoritative almanac rather than assuming a fixed Gregorian date.
References
-
Calculation and input contract: japanese-calendar/hachijuhachiya — tool.io
-
Glossary on Solar Terms: Zassetsu — National Astronomical Observatory of Japan
Similar or alternative tools
- Japanese Nihyakutoka Date Calculator
Add 209 days to verifiedRisshunDate and return inclusiveOrdinal 210.
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Count open entries until requiredOpenDays and return that date, otherwise an empty deadline and found false.