When did auspicious and inauspicious day divination begin?
The practice of choosing auspicious and inauspicious days printed in today's van su almanacs descends from a textual tradition already systematized by at least the 3rd century BCE. Rishu day books (Chinese: rishu) excavated from Warring States, Qin and Han tombs show that people already recorded days for action and days for avoidance according to a consistent editorial logic, used for choosing wedding days, burial days, groundbreaking and travel. This is historical evidence for the age of the tradition, not proof that good days are actually better than bad ones. This article traces that tradition through archaeological texts, scholarly research and its transformation into today's van su almanacs.
Marc Kalinowski, in a 1986 research article in the journal T'oung Pao, analyzed the Shuihudi day books and concluded that day selection had become systematized by the 3rd century BCE. This is a level A research finding, widely accepted among researchers.
What is the Shuihudi day book and who used it?
The Shuihudi day book is a collection of bamboo slips excavated in 1975 in Yunmeng county, Hubei province, China, from the tomb of a Qin official. According to Kalinowski's 2008 analysis in T'oung Pao, Set A of this day book was edited according to a consistent logic: days of the year were classified by the sexagenary cycle and by the jianchu system, each day tied to an activity to be done or avoided. This editing style shows that users did not consult randomly but had a complete calendar system to consult.
According to Kalinowski, users of Qin and Han day books included both local officials and commoners, since bamboo slips recording auspicious and inauspicious days were placed in tombs as burial goods. This shows that day selection had permeated daily life, not just court ritual.
Donald Harper and Marc Kalinowski (eds.), in the book Books of Fate and Popular Culture in Early China (Brill, 2017), gathered research on excavated day books, confirming the connection between these ancient texts and the almanacs still used today. This is a level A collective work, providing an overall picture of the development of day selection from the Warring States to the Han.
Day selection in ancient popular religious life
Mu-chou Poo, in the book In Search of Personal Welfare: A View of Ancient Chinese Religion (SUNY Press, 1998), argues that day selection and taboos were central to everyday religious life in ancient China. People not only sought divine protection in major rituals but also consulted auspicious and inauspicious days for small matters like going to market, farming or sewing clothes. This is a level A research finding, based on analysis of archaeological texts and contemporary records.
Poo shows that the day-selection system was not only a product of the intellectual class but also a tool for ordinary people to cope with life's uncertainties. Day selection became part of popular religion, where people sought to control personal fate through ritual actions.
Dunhuang manuscripts and the spread of medieval day-selection almanacs
Marc Kalinowski, in a 2003 study, analyzed medieval Dunhuang manuscripts, showing that day-selection almanacs continued to be copied and widely circulated through the centuries. These manuscripts not only repeated the Qin and Han system but added new rules, reflecting the development of astronomy and astrology in later periods.
The Dunhuang manuscripts show that medieval day-selection almanacs integrated elements from Buddhism and Daoism, creating a more complex system than the Qin day books. This is a scholarly interpretation of textual content, not a claim about the efficacy of day selection.
Tung-shu and imperial almanacs: the structure of a day-selection almanac
Richard J. Smith, in the book Chinese Almanacs (Oxford University Press, 1992), described the structure of the t'ung-shu, the type of day-selection almanac printed and sold widely in China and countries influenced by Han culture. A typical t'ung-shu includes sections: the lunar calendar, auspicious and inauspicious days by sexagenary cycle, stars and favourable directions for each day, and advice on what to do. This structure was standardized from the Ming and Qing dynasties and is still maintained in today's van su almanacs.
Smith also notes that the t'ung-shu was not only a reference tool but also part of the commercial publishing market, with many printers competing. This explains why t'ung-shu versions may differ in detail despite sharing a common theoretical system.
In Vietnam: Han-Nom day-selection books under the monarchy
Alexei Volkov, in a 2013 research article in the journal Extrême-Orient, Extrême-Occident, surveyed Han-Nom day-selection texts of Vietnam under the monarchy. He shows that the Vietnamese not only received the day-selection system from China but also compiled their own day-selection books, integrating local and Buddhist elements. These books circulated in the court and among the people, serving the need to choose days for important rituals such as weddings, funerals and groundbreaking.
According to Volkov, Han-Nom day-selection books often combined the Chinese sexagenary system with Vietnamese folk beliefs about auspicious and inauspicious days. This is an interpretation of textual content, not a claim that those beliefs have practical efficacy.
Which layers of that history do the sections in Nhat Nguyet's day-viewing utility come from?
Nhat Nguyet's day-viewing utility inherits textual layers formed over many centuries. Kind of knowledge: School: Nhat NguyetSchool's interpretation. How one school or one book reads it; other schools may read it differently. The five labelsThe lunar calendar and sexagenary sections are based on traditional calendrics, verifiable against printed calendars or independent spreadsheets. The auspicious and inauspicious day sections by jianchu and star positions are based on the system recorded in Qin and Han day books and Ming and Qing t'ung-shu. The advice sections on what to do by day are the site's interpretation, based on rules edited to suit contemporary Vietnamese context.
The sections in Nhat Nguyet's day-viewing utility do not aim to claim that a good day will bring good results or a bad day will bring bad results. We provide information based on the existing textual tradition, for users to consult and decide for themselves.
Does it work? The boundary between historical fact and practical efficacy
The age of the day-selection tradition is a historical fact. However, the current research catalogue contains no experiment verifying the efficacy of auspicious and inauspicious days. Studies on the effects of belief in auspicious and inauspicious days usually focus on economic behaviour, such as choosing wedding days and real estate transactions, and are conducted in other countries, not on Vietnamese people.
Kind of knowledge: UnprovenNot enough evidence. Someone has claimed it, but no source or study is strong enough to confirm it. The five labelsThere is currently no research in the catalogue verifying whether good days actually bring better results than bad days. This is an evidence gap, not negative evidence.
Some studies abroad show that belief in auspicious days can influence economic behaviour, for example choosing wedding days or contract-signing days, which can affect market outcomes. However, this is an effect of belief on behaviour, not proof that the auspicious day itself has efficacy. These studies are conducted abroad and cannot be extrapolated to Vietnamese people without research on Vietnamese people.
Table: Layers of day-selection texts through the periods
| Period | Type of text | Main features | Reference |
|---|---|---|---|
| Warring States, Qin, Han (3rd c. BCE - 3rd c. CE) | Excavated day books (Shuihudi, etc.) | Records days to do and avoid by sexagenary cycle and jianchu; used by both officials and commoners | Kalinowski 1986, 2008; Harper & Kalinowski 2017 |
| Medieval (Dunhuang, 8th-10th c.) | Dunhuang manuscripts | Added Buddhist and Daoist elements; more complex system | Kalinowski 2003 |
| Ming and Qing (14th-20th c.) | T'ung-shu, imperial almanacs | Standardized structure: lunar calendar, auspicious and inauspicious days, stars, favourable directions | Smith 1992 |
| Vietnam under the monarchy (15th-19th c.) | Han-Nom day-selection books | Combined Chinese system with local and Buddhist beliefs | Volkov 2013 |
| Modern | Van su almanacs, day-viewing utilities | Inherit the above layers, add digital interface and site interpretation | Synthesized from the above sources |
Conclusion: a long textual tradition and its boundaries
Auspicious and inauspicious day divination is a textual tradition with a compilation history traceable at least to the 3rd century BCE, through excavated day books, Dunhuang manuscripts, Ming and Qing t'ung-shu and Vietnamese Han-Nom day-selection books. That age is a historical fact, not proof that good days are actually better than bad ones. This article does not deny the utility of day viewing but only clarifies its origins and boundaries. To learn more about the custom of choosing days in Vietnamese life, you can read the article Auspicious and Inauspicious Day Viewing in Weddings and Groundbreaking: The Vietnamese Custom of Choosing Good Days and Months.
