Sukuyo comparisons: zodiac, nakshatras and Rokuyo
Sukuyo comparisons should separate each system’s input, reference frame, calculation, and output; shared Moon terms do not make results equivalent.
Overview
Start with the quantity each tool returns. Different definitions can produce different answers without either result being an arithmetic error.
At a glance
- Sukuyo
- Converted lunar-date mansion
- Moon sign / nakshatra
- Declared longitude-based position
- Rokuyō
- Six calendar annotations
Explore concepts
- Sukuyo study guide
Japanese astrology comparison: zodiac versus Sukuyo
Japanese astrology includes multiple systems: the animal-year cycle, 12 zodiac signs, and Sukuyo’s 27 birth mansions use different inputs and outputs.
Read definition - Sukuyo study guide
Sukuyo and nakshatra: why lunar mansions can differ
Sukuyo and nakshatra use lunar-mansion terms, but date-table and longitude-based results are not interchangeable; compare inputs, zodiac, and assignment rules.
Read definition - Sukuyo study guide
Sukuyo vs Moon sign: date table and lunar longitude
Sukuyo vs Moon sign compares different outputs: a declared zodiac longitude versus OpenFate’s 27-entry lunar-date table.
Read definition - Sukuyo study guide
Sukuyo vs Rokuyo: 宿曜 and 六曜 are different
Sukuyo vs Rokuyo compares different systems: Rokuyo names six calendar annotations, while Sukuyo uses a 27-mansion birth lookup and relative cycles.
Read definition
Ask what is being calculated
A birth-date table, a celestial longitude and a date annotation are different quantities.
A shared name or symbol cannot establish numerical equivalence.
Compare the inputs
Sukuyo’s current product uses a civil date. A precise Moon position needs a suitable instant and coordinate convention.
Do not invent the missing input merely to make two systems agree.
Compare the reference frame
A tropical sign and a sidereal nakshatra use different reference choices.
A Japanese twelve-animal year label answers a different question again.
Keep each result labeled
A person may consult several traditions, but the outputs should retain their system names and settings.
Do not present a combined identity as a deterministic field that neither method calculated.
Choose the useful next page
Use the dedicated comparisons for Japanese zodiac, nakshatras, Moon signs and Rokuyō.
The purpose is to prevent confusion, not to prove that one symbolic system predicts life better than another.
Use a four-column comparison
Create one row per system with four columns: input, calculation rule, output size, and interpretation layer.
Row 1 is civil date → lunisolar lookup → 27-mansion name. Row 2 is timestamp → longitude → 12-sign Moon position. Different questions can validly disagree, so do not blend labels.
Sources and editorial basis
- 宿曜經 · T1299 卷上卷上「分定宿直品第一」and「大唐月建圖」: mansion/palace vocabulary and date lookup, not universal equivalence with other systems.Historical text for mansion names and calendar tables. Its table is not identical to OpenFate’s modern 27-mansion lookup; it does not establish predictive validity.
- OpenFate Sukuyo calculator and calculation conventionEditorial code check 2026-09-10, policy 1.0.0: comparisons; policy.ts, constants.ts, engine.ts and traditional-cycles.ts. Product settings are not an independent historical authority; practical examples are OpenFate editorial applications.Product-specific input and output reference. Editorial checks also inspected policy 1.0.0 and the month-start constants on 2026-09-10; those implementation checks are not an independent traditional authority.
- Swiss Ephemeris: Sidereal Ephemerides for AstrologySwiss Ephemeris documentation §2.8.1 The problem of defining the zodiac: tropical/sidereal origins and ayanamsha; §2.1 planetary and lunar ephemerides.Technical reference for tropical/sidereal frames and ayanamsha choices. Longitude calculation and symbolic interpretation remain separate.
- 国立国会図書館：日本の暦・六曜日本の暦 第三章「吉凶を表す言葉①六曜」: six current names and calendar-annotation distinction.Reference for the six Rokuyo calendar names. Their cultural meanings do not validate outcomes or make them Sukuyo relationship roles.
- 国立天文台 暦Wiki：十二支暦Wiki「十二支」: twelve names and their readings; not a birth-mansion calculation.Reference for the twelve-branch nomenclature, distinct from a 27-mansion birth-date lookup.