Ming Gua Calculation: Finding Your Personal Gua Number

Ming Gua (命卦) is the personal trigram number calculated from your birth year and gender. It is the foundation of Eight Mansions (八宅) feng shui: the system tells you, based on your Gua number, which compass directions are favourable for sleeping, working, and facing, and which are best avoided. The system is simple, mechanical, and has been in use for centuries.

But Ming Gua has a narrow purpose. It is a directional tool — it tells you which way to face, not who you are. It is not a personality test, a compatibility score, or a prediction of your fate. If your Gua number says you should face East to sleep, that is a spatial suggestion, not a cosmic decree. The goal is to help you orient your body in a way that, according to the Eight Mansions theory, supports your energy. Nothing more.

The calculation uses your birth year in the Chinese lunar calendar. The formula differs for males and females. Here is the step-by-step process:

The nine Gua numbers are divided into two groups: East Group (East, Southeast, South, North) and West Group (West, Northwest, Southwest, Northeast). Your Gua number determines which group you belong to and which four directions are favourable:

A couple shares a home. The husband, born in 1982, has a Gua of 1 (Kan, East Group). The wife, born in 1985, has a Gua of 8 (Gen, West Group). They are in different groups, which means their favourable directions are different and sometimes opposite.

The husband's best direction is Southeast (Sheng Qi, 生气). The wife's best direction is Southwest (also Sheng Qi for her). Their bedroom happens to be in the Southwest sector of the house. This is excellent for the wife — her bed faces her best direction. But the husband's best direction is Southeast, which is the kitchen in this house.

The practical compromise: the husband cannot sleep in the kitchen. Instead, he adjusts his home office desk to face Southeast, his best direction, while he works. When he sleeps, he faces Southwest, which is his wife's best direction but is still a neutral direction for him (not one of his four unfavourable directions). The wife's desk faces Southwest, her best direction. Both are satisfied with the arrangement.

The lesson: two people with different Gua numbers in the same house will rarely have perfect directional alignment. The goal is to make the best of what is available. Prioritise the bed direction for the person who is more sensitive to sleep quality. Prioritise the desk direction for the person who works from home. A Gua number is a tool for optimisation, not a reason for conflict.

Ming Gua is a simple, mechanical system that has been used for centuries. It gives you a clear, deterministic answer: face this direction, avoid that direction. That clarity is appealing, but it is also its limitation. The system reduces a person to their birth year and gender, ignoring everything else about their body, preferences, and circumstances. Use Ming Gua as a starting point for orienting your furniture, but do not let it override your own experience. If your Gua says to face North but facing North gives you a stiff neck, turn the chair. Your body knows more about what feels right than a formula based on your birth year.