When does Yang Dun begin each year?

Yang Dun begins at the Winter Solstice, no exceptions when you need accuracy

Yang Dun begins at the exact astronomical moment of Winter Solstice each year. Your charts, decisions, and strategic windows follow that pivot point, not the Lunar New Year.

How the rule works in practice

Yang Dun is the polarity that governs the six months following Winter Solstice. Yang Dun sets the operating frame for the yearly Qi Men Dun Jia chart because the system is solar by design and uses solar terms to define its seasonal switches.

What those words mean in functional terms

8 Doors are the actionable outcomes inside a Qi Men Dun Jia chart, such as Open for opportunity, Rest for protection, and Death for endings. 9 Stars are the energetic qualities assigned to palaces, each giving tactical color like leadership or support. 8 Gods are moral and situational influences that modify how a Door or Star behaves. Heaven panel is the heavenly layer carrying Stars and timing information, while Earth panel carries positions tied to physical locations and people. Three Wonders is the combination of Heaven, Earth, and Human timing used to validate a move. Six Instruments are the technical tools for calculation and rectification of charts. These components must be set against the correct Dun polarity to be reliable.

Calculate the moment, precisely

Find the exact astronomical time of Winter Solstice for your year using a reliable ephemeris or planetarium software. Convert that moment into your local standard time and then into local solar time if you require millimeter precision.

Apply the conversion because Qi Men Dun Jia is tied to the Sun. Use the exact moment, not the day, when you decide whether a plan sits in Yang Dun or the preceding Yin Dun. Use a software that outputs the solstice in UTC, then shift into your timezone and adjust for longitude if you want solar noon alignment.

Why the Winter Solstice and not New Year

Winter Solstice is the astronomical nadir of solar northern hemisphere declination from which yang energy begins to return. Using the solstice aligns Qi Men charts with the true seasonal vector rather than the cultural placement of the Lunar New Year. Using Lunar New Year will systematically misplace your annual Heaven panel and Earth panel, and that error compounds strategic mistakes when you read 8 Doors, 9 Stars, and 8 Gods.

What to do when your decision falls near the solstice

Calculate the exact moment and treat the solstice as a hard switch. If a decision crosses the solstice within hours, recompute your chart at both moments. If outcomes change between the Yang Dun and Yin Dun versions then the moment matters and you must act based on the polarity that will be in effect when the action occurs.

Practical step by step

• Obtain the precise UTC time of Winter Solstice from an authoritative ephemeris for the year in question.
• Convert UTC into your local standard time, and if necessary convert into local solar time by adjusting for longitude to the standard meridian.
• Mark the solstice moment as the start of Yang Dun for that solar year, and mark the Summer Solstice as the start of Yin Dun six months later.
• Cast annual charts using the solstice moment to set the Heaven panel and Earth panel before placing 9 Stars, 8 Doors, and 8 Gods.
• Validate decisions within the Three Wonders framework and use the Six Instruments only after the correct Dun polarity is set.

Edge cases and common errors

Many practitioners use the Lunar New Year or the first Jia Zi day to start the annual Dun and that creates chronic mis-timings. Use the solstice method if you want reproducible results that map to natural solar cycles. Some schools use Beijing standard time as a convention; that is acceptable only if every chart you compare was created with that same convention.

Ignore half-measures like rounding to the nearest day. Treat the solstice moment as precise because several Doors and Stars can flip palace positions with hours difference. Buy or script a reliable ephemeris and test it against astronomical tables before you trust a year of strategy to a casual date lookup.

Application examples

When evaluating a corporate annual plan, cast the annual chart at the Winter Solstice. If you are scheduling a merger for the first quarter, assess whether the merger will fall into Yang Dun influence for the year and adjust timing if the Doors and 9 Stars favor a different polarity. When looking at personal forecasts, understand that a birthday after the Winter Solstice belongs to that Yang Dun year even if culturally it feels like the previous year.

When timing is the decision, the solstice is the judge. Use it without apology and accept the moments it forces on you.

Short rules for real work

Use Winter Solstice as the annual pivot. Use precise astronomical time. Convert to local time in all calculations. Validate with Three Wonders before acting. Use the Six Instruments only under the correct Dun polarity to avoid compounding errors.

Yang Dun begins at the exact astronomical moment of Winter Solstice; everything that follows flows from that moment.