About Nhật Nguyệt
Four kinds of knowledge on Nhật Nguyệt
A lunar date, a festival, a birth chart and a personality type cannot be checked the same way. Every article and tool carries a label at the top saying which of the kinds below it belongs to.
Calendar and astronomy
Lunar dates, solar terms, stems and branches, days and hours. The same input always gives the same result, and the result can be cross-checked against a printed almanac or an independent calculation. An error here is a calculation error, and it is fixed as one.
Article topics: Lunar calendar
- Vietnamese lunar calendar. Lunar dates, stems and branches and solar terms are computed; auspicious hours are a date-selection convention.
- Lunar-solar converter
Culture and belief
Customs, festivals, beliefs, traditional crafts, history and Vietnam's ethnic communities. The site records what people do and believe, and does not rule on whether the belief is true. What can be checked is whether the record matches the documents: dates, places, names, rites and sources.
Article topics: Traditional festivals, Tet and seasonal rites, Vu Lan festival, Festival customs, Tet customs, Regional customs, Regions, Folk belief, Ethnic minority belief, Ancestor worship, Buddhism, Life-cycle rites, Ethnic minority customs, Vietnam's ethnic communities, Traditional crafts, Traditional performing arts, Traditional dress, Traditional food, Vietnamese commemorative days, Historical figures, Folk taboos
- The 64 hexagrams. A classical text, checkable against the original.
- Vietnamese festival calendar. Festivals, names and venues follow documentary sources; lunar dates are converted by calculation.
- Rite customs lookup. The days or months for each rite follow sourced custom; lunar and solar dates come from calendar computation.
Traditional systems
Tử Vi, Bát Tự, the I Ching read for questions, feng shui, face reading, date selection and age compatibility. These are long-standing interpretive systems with their own books and schools, and they have no scientific basis. The site presents them as the books do, says where the schools disagree, and makes no claim that they work. Charts and tables are computed by machine under the books' conventions; what can be checked is whether the machine follows those conventions correctly, not whether a reading fits anyone's life.
Article topics: Vietnamese astrology, Zi Wei Dou Shu, BaZi, Saju, Tam Thức, Feng shui, Vastu Shastra, Feng shui stones, Five Elements, I Ching, Physiognomy, Face reading, Palmistry, Folk traditional practices, Zodiac animals, The twelve zodiac animals, Date selection, Date and hour selection, Astrology, Western astrology
- Tử Vi: how the palaces connect
- Ask the coins
- Tử Vi chart
- Couple compatibility: marriage & partnership
- Auspicious hours. The stems and branches of the day and hour are computed; which hours count as auspicious is a date-selection convention.
- Western zodiac (Sun sign). Astrology has ancient Greek roots; reading by the Sun sign alone only became common in the 20th century.
- Yearly star (Nine Luminaries) & Tam Tai
- Luban rule. The measurement is arithmetic; which sectors of the rule are lucky is a feng shui convention.
- Cast a hexagram
- House-building year check
- New Year first-footer check
- Wedding date picker. Lunar dates and stems and branches are computed; auspicious hours, avoided months and age fit are date-selection conventions.
- House direction lookup
- Best day for a purpose. Lunar dates and stems and branches are computed; which days suit a task or an age is a date-selection convention.
- Face reading
- Palm reading
- 2026 Yearly Star and Tam Tai. Yearly stars and Tam Tai follow traditional systems; the Pinnacle periods follow numerology, a modern system.
- What energy do you carry. The Four Pillars and nạp âm layers are traditional systems; the numerology layer is a modern system.
- How is today for me. Stems and branches and solar terms are computed; the day officer, hexagram and Five Elements are date-selection conventions; numerology is a modern system.
- Name your child
- Child's birth year by parents' ages. Lunar years, Tết and solar terms come from calendar computation; the matches and clashes of stems, branches and Nạp Âm are folk conventions for matching ages.
- Bát Tự chart
Modern system
MBTI, the Enneagram, Human Design, name-and-birthday numerology, Tarot and playing-card reading. Many borrow old names or symbols but took shape recently: name-and-birthday numerology formed in the late 19th century and only borrows Pythagorean number philosophy; Tarot began in the 15th century as a card game, was used for divination from the late 18th century, and the reading style common today took shape with the Rider-Waite deck of 1909. The site does not present them as ancient traditions, and states the state of research where there is any.
Article topics: Numerology, Tarot, Playing-card reading, MBTI, Enneagram, Human Design
Topics between two kinds
The I Ching is a classical text and is also used for divination; an almanac is calendar arithmetic plus a date-selection convention. In such cases the label gives the kind that covers most of the content, and tools say which part is computed and which is convention, as in the list above. The 64-hexagram reference tool is filed under culture because it reads the text; I Ching articles are filed under traditional systems because most of them read hexagrams to answer questions.
Articles that analyse these systems through psychology or the philosophy of science carry no label: they do not present a system, they examine systems from outside.
Labels inside an article
An article belongs to one kind, but its paragraphs are not all checkable to the same degree. A label at the start of a paragraph covers the whole paragraph; a label inside a paragraph covers only the dotted-underlined sentence after it. Paragraphs without a label are Nhật Nguyệt's own framing and explanation.
Computed by calendar arithmetic, and checkable against a printed almanac or an independent calculation. Lookup rules of traditional systems, such as placing stars or spirit-stars, are a book's convention even when a machine computes them, so they carry the school label.
Backed by a document, a date and a source; the note number beside it points to that source.
What people believe, avoid or pass on by word of mouth, recorded as a belief, not as a checked fact.
How one school or one book reads it; other schools may read it differently. Where known, the label names the school or the book.
Someone has claimed it, but no source or study is strong enough to confirm it.