Description
Return a year-level Japanese-era arithmetic conversion and boundary flag.
Language and manuscript records use explicit source labels, scripts, era-year conventions and text/area units. A literal split, Unicode slot or page-area calculation preserves supplied notation without resolving pronunciation, historical dates, manuscript identity or conservation needs.
Return a year-level Japanese-era arithmetic conversion and boundary flag.
When to use this tool
Use Japanese Era Boundary Ambiguity when checking the stated language, manuscript, era-label or Unicode convention.
How to use the tool and how it works
- Enter eraStartGregorianYear, eraYear, monthDayKnown, boundaryWithinYear. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read gregorianYear, needsBoundaryCheck. Inspect needsBoundaryCheck before interpreting the associated values.
Return a year-level Japanese-era arithmetic conversion and boundary flag. Require supplied start year and eraYear 1..9999; gregorianYear = start+eraYear-1, needsBoundaryCheck requires first era year, a within-year boundary and unknown month/day.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| eraStartGregorianYear | Era Start Gregorian Year | Required. Safe integer; minimum 1; maximum 9999. |
| eraYear | Era Year | Required. Safe integer; minimum 1; maximum 9999. |
| monthDayKnown | Month Day Known | Required. Boolean. |
| boundaryWithinYear | Boundary Within Year | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| gregorianYear | Gregorian Year | Required. Safe integer. |
| needsBoundaryCheck | Flags only unknown month/day in the supplied first-era-year boundary scenario; not a complete date-validity test. | Required. Boolean. |
{
"input": {
"eraStartGregorianYear": 2019,
"eraYear": 1,
"monthDayKnown": false,
"boundaryWithinYear": true
},
"output": {
"gregorianYear": 2019,
"needsBoundaryCheck": true
}
}Limitations and assumptions
- The start year is supplied and output may exceed 9999; no era table, actual date validation or later-era-end boundary check is performed.
- 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.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect the original text/manuscript and its documented language, edition, calendar and encoding conventions for substantive linguistic, historical or conservation interpretation.
References
Similar or alternative tools
- Era Label Source Identifier
Serialize an era-label source identifier.
- Public Era Year Token
Parse a supplied era label and positive year suffix.