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.
Overview
Retain 宿曜 and 六曜 in the comparison. Their similar sound and repeated count of six do not make their tables compatible.
At a glance
- Sukuyo
- 宿曜
- Rokuyō
- 六曜
- Rokuyō names
- 先勝・友引・先負・仏滅・大安・赤口
Check the characters
宿曜 contains the character for mansion; 六曜 contains the number six.
Romanized search strings can hide that distinction, so retain the original characters when comparing sources.
A calendar annotation is not a birth mansion
A Rokuyō label such as 大安 describes a date in that calendar tradition. It does not identify a person’s Sukuyo mansion.
Do not put the six Rokuyō names into a 27-position relationship table.
Six is not the same classification
Sukuyo has six relationship families and a separate six-role reference, neither of which is the Rokuyō sequence.
The shared count is not an equivalence rule.
Compare date methods separately
A calendar may print Rokuyō beside mansion or weekday information. Read each column’s heading and method.
A disagreement between columns is not necessarily a calculation error.
Do not infer a shared forecast
Combining auspicious labels from different traditions does not produce a measured success probability.
Use cultural date preferences voluntarily while keeping practical plans, consent and safety independent.
Read a mixed calendar by columns
When one calendar shows 六曜, weekday and 宿曜 together, trace each heading to its own method and retain all three labels separately.
大安 beside a mansion does not convert that mansion into Rokuyo, and apparent disagreement between columns is not necessarily a calculation error.
Sources and editorial basis
- 宿曜經 · T1299 卷下卷下「三必祕要法」relative mansion roles; these are not the six Rokuyo calendar names.The three-nine passage supplies historical relative-position terminology. It is not evidence that a modern relationship outcome is determined by a mansion pair.
- OpenFate Sukuyo calculator and calculation conventionEditorial code check 2026-09-10, policy 1.0.0: rokuyo; 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.
- 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.