The almanac says suitable for marriage, so why might that day be inauspicious for you
KarmaSpace translation

When the almanac says suitable for marriage, it only states the nature of that day itself, the same for everyone. To know whether that day is usable for you, two more layers must be checked: whether the day branch clashes with your zodiac sign or the day branch of your BaZi, and the auspiciousness or inauspiciousness of the twelve day officers and the yellow and black paths. On a day that clashes with your zodiac sign, however good the almanac says it is, you should still avoid it.
The most common way to pick a date by consulting the almanac is to find a day marked suitable for marriage or suitable for opening a business and settle on it. This step is not wrong, but it is only half the job.
The suitable and unsuitable items in the almanac are calculated from the day s heavenly stems and earthly branches, the twelve Jian Chu officers and the presiding day deity. They describe the nature of that day itself, with no relation to who is reading the almanac. For the same day, the same sentence is written for ten thousand people.
The second layer: does that day clash with you
The earthly branch of each day clashes with one zodiac sign. A chou day clashes with the goat, a wu day clashes with the rat, and so on. When the almanac writes clash with the ox of ding chou, this is what it refers to.
If the clash that day happens to fall on your own zodiac sign, no matter how favourable the almanac reads, you should step aside. The traditional saying is that a day clash should not be used, and the reasoning is not mysterious: it is a reminder that the energy of that day is in conflict with you personally, so it is not suitable to begin a long-term matter on that day.
A finer layer is the clash with the day branch, that is, the earthly branch of the day pillar in your BaZi chart. The day pillar represents yourself and the spouse palace, and a clash with the day branch is more personal than a clash with your zodiac sign. Matters involving relationships, such as marriage or signing a contract, should especially be avoided.
Third layer: the Twelve Officers and the Yellow and Black Paths
The twelve officers of Jian Chu (Establish, Remove, Full, Balance, Settle, Hold, Break, Danger, Complete, Receive, Open, Close) are another system of judgement. What you actually need to remember is only the two ends: Complete and Open are most suitable for starting things, while Break and Close are most taboo.
The ones in between each have their own leanings. Settle is suitable for placing a bed or installing a door, but not for travel. Hold is suitable for capturing and tidying, but not for new ventures. The twelve deities of the Yellow and Black Paths (Azure Dragon, Bright Hall, Heavenly Punishment, Vermilion Bird, and so on) are another layer of auspicious and inauspicious markers. When the deity on duty falls on the Yellow Path, things flow smoothly; when it falls on the Black Path, take care.
Only when these three layers are stacked together do you get a day that is meaningful for you.
Different matters look at different terms
The almanac will not write opening a shop. It writes opening the market, establishing a bond, trading, and receiving wealth. It will not write moving house. It writes entering the residence, relocating, and placing the bed. Renovation is not renovation; it is breaking ground, building and repairing, laying the foundation, and raising the beam.
So before choosing a day, you first need to translate what you intend to do into the almanac language. Otherwise you will miss half the days that actually suit you, and you will misuse some days that look relevant but are in fact not.
Cast it yourself once
The date selection tool on this site is built in exactly this order: first match the matter against the almanac recommendations and avoidances, then look at the Twelve Officers and the Yellow and Black Paths scoring, and finally remove outright the days that clash with your zodiac sign and your day branch, telling you how many days were removed and why.
The results list three tiers: best, second choice, and usable. Each day comes with its auspicious hours and what it clashes with that day. Everything is calculated locally, no login is needed, and no Xuan Jin is deducted.
A final reminder
Date selection is about starting a matter on a smoother day, not a guarantee of the outcome. However well the day is chosen, if the contract terms are unreasonable you still should not sign. On this point, no almanac will take responsibility for you.
常見問題
問Is a day the almanac marks as suitable for marriage necessarily a good day?
Not necessarily. The almanac calculates suitability and avoidance by the day stem and branch, the twelve day officers, and the duty deity, the same for everyone. If that day branch clashes with your zodiac sign or day branch, it is not suitable for you personally.
問What is the difference between a day branch clash and a zodiac clash?
A zodiac clash looks at the year branch; a day branch clash looks at the branch of the day pillar in BaZi. The day pillar represents oneself and the spouse palace, so a day branch clash is more personal than a zodiac clash; matters related to relationships, such as marriage and signing contracts, should especially avoid it.
問Which of the twelve day officers are most suitable for doing things?
Completion and Opening are best for starting affairs; Destruction and Closing are most taboo. The ones in between each have their leanings; for example, Stability is suitable for placing a bed or installing a door but not for travel, and Execution is suitable for tidying up but not for new ventures.
問Which terms should be checked in the almanac for moving house?
The almanac does not write moving house; you look at entering the residence, relocating, and placing the bed. For opening a business, look at opening market, establishing contracts, trading, and receiving wealth; for renovation, look at breaking ground and building.