LEARN TONG SHU
How to choose an auspicious date, properly.
Long before apps, every Chinese household kept a Tong Shu (通书) — the imperial almanac that graded each day of the year for weddings, moving house, signing contracts, breaking ground. Date selection (择日) is arguably the oldest living art in Chinese metaphysics, and it is ruthlessly practical: not 'is today lucky?' but 'is today right for this, for me?'. This guide explains how the grading works and how to use a modern version of the same calendar.
The almanac tradition
The Tong Shu — sometimes called the 'old yellow calendar' (黄历) — has been printed in some form for over a thousand years. Court astronomers computed the year's days and graded them; households planned around the grades. Weddings, shop openings, roof-raising, even haircuts had their entries. The tradition never disappeared: printers in Hong Kong and Taiwan still sell millions of copies every year.
What survives in that format is a genuine computational system, not folklore. Each day carries a stem-branch signature, a ruling 'officer', a set of spirits for and against, and a list of activities the day supports or undermines. The almanac is a database rendered as a calendar.
What makes a day 'auspicious'
The backbone of the system is the twelve Day Officers (建除十二神) — a rotating cycle of twelve day-types, each with a distinct temperament. Establish days favour beginnings. Open days favour launches and openings. Balance days favour stability. Close days favour finishing. Remove days favour ending what should be ended. The officer sets the day's basic grammar.
Layered on top are the day's stem-branch interactions: harmonious combinations that strengthen a day, clashes that strain it, and a long list of benefic and malefic spirits inherited from older astronomy. The final grade is a synthesis — which is why two adjacent days can receive very different verdicts.
Match the date to the activity
The first rule of date selection is that 'auspicious' has no meaning without an activity attached. An Open day is excellent for launching a product and pointless for recovering from one. A Remove day is perfect for resigning, decluttering or ending a contract — and a poor choice for signing a new one. The almanac grades per activity for exactly this reason.
So start with the verb, not the calendar. Define what you are actually doing — marrying, signing, moving, launching, travelling, breaking ground — and only then look for the days whose temperament matches. This single habit eliminates most of the superstition and keeps the part that is genuinely useful.
Match the date to the person
The second rule is the one generic 'lucky day' lists always break: a day interacts with your chart. The most common filter is the clash (冲) — a day whose Earthly Branch opposes the branch of your birth year is traditionally avoided for important undertakings, whatever the almanac says about the day in general.
This is why two friends can look at the same 'excellent for weddings' date and correctly reach different conclusions. The day is the weather; your chart is the boat. A serious date selection checks both — which is exactly what a computed calendar can do and a printed list cannot.
Green, gold and crimson: a simpler reading
The full classical grading is dense, so modern practice often compresses it. We use three tiers. Green days: broadly supportive for most activities — proceed. Gold days: the month's best, reserved for the things that matter most. Crimson days: strained — schedule around them for anything important, and use them for routine instead.
Compression loses some nuance, and that is a fair trade. A calendar you actually consult beats a perfect system you never open. The tiering keeps the two rules intact — the day's own quality, flagged against your chart where it matters — and presents it as a decision, not a dissertation.
Putting it into practice
This month's calendar is already computed for you: every day graded, with the clashes that apply to your own chart marked once you have cast it. The practice is simple — pick the one important thing you are planning this month, find a green or gold day that does not clash with you, and schedule it there. That is date selection as it was always meant to be used.
Start with the auspicious dates calendar, or cast your free chart first so the calendar can grade days against your chart as well as in general. One well-chosen date a month is a reasonable ambition; the almanac was never about living by the calendar, only about not rowing against it.