The Beginning of Winter Solar Term and Its Important Role in BaZi Metaphysics

Lidong (Beginning of Winter) is the nineteenth solar term among the 24 solar terms, marking the start of winter. According to the division by the sun’s celestial longitude, Lidong occurs when the sun’s celestial longitude reaches 225°, generally between November 7 and 8 each year. The month pillar (Yue Jian) at Lidong corresponds to Hai (亥, Hài), which contains hidden Ren Water (壬, Rén) and Jia Wood (甲, Jiǎ), symbolizing the strengthening of water energy and the gradual formation of the cold Yin energy characteristic of winter.

Solar terms are time nodes obtained by equally dividing the sun’s path along the ecliptic into 24 segments. As the first solar term of winter, Lidong signifies the arrival of cold weather climatically and holds an extremely important position in metaphysics. Unlike the traditional lunar calendar month division, the Lidong solar term establishes the starting point of the winter month pillar.

In BaZi metaphysics, the division of the month pillar is not based on the lunar calendar’s first day but on the transition of solar terms. This means that the arrival of Lidong represents the official start of the winter month pillar, influencing a person’s BaZi chart and fate trajectory. Since solar terms represent the sun’s celestial longitude position and have astronomical and natural scientific basis, metaphysics adopts solar terms as the true boundary for determining the month pillar and the beginning of Da Yun (decade luck cycles) for greater accuracy.

The month pillar at Lidong is Hai (亥, Hài), which conceals Ren Water (壬, Rén) and Jia Wood (甲, Jiǎ), showing the characteristic abundance of water energy in winter. In the Five Elements (Wu Xing) cycle of generation and overcoming, the flourishing water corresponds to coldness and storage, reflecting the Yin-Yang changes in winter. Metaphysicians determine the month pillar using the time point of Lidong to more precisely reflect the cosmic energy field at a person’s birth, thereby calculating their innate destiny and fortune changes.

In practical BaZi charting and Da Yun calculation, the time point of the Lidong solar term plays a decisive role. If a person’s birth date is close to the Lidong solar term, the metaphysician must use the exact time of the solar term transition as the boundary to determine the month pillar’s corresponding solar term month. This approach avoids errors caused by the fluctuating date of the lunar calendar’s first day, ensuring the accuracy of metaphysical analysis.

For example, if a person is born in the early morning of November 7, when the sun’s celestial longitude has just reached or exceeded 225°, it means the person was born after Lidong. Their month pillar should be based on the winter month of Hai (亥, Hài), not the previous solar term month. This configuration is especially important when analyzing the strength and weakness of the Five Elements and the trend of luck cycles, revealing the influence of abundant water energy on the destiny and its manifestation in Da Yun.

Many people mistakenly believe that the month pillar in BaZi is determined by the lunar calendar’s first day, but metaphysics strictly follows the solar term division standard. Ignoring the precise time of solar terms leads to incorrect month pillar judgment, which in turn affects the calculation of Da Yun and Liu Nian (annual fortune), causing deviations in metaphysical analysis.

Another common misconception is overlooking the role of the Lidong solar term in starting Da Yun. Because the solar term time fluctuates by one to two days each year, metaphysicians must accurately grasp the exact time of Lidong to correctly determine the starting point of Da Yun and avoid misjudgments caused by inaccurate time calculations.

Question: Why is the BaZi month pillar determined by solar term transitions instead of the lunar calendar’s first day? Answer: Because solar terms are scientifically divided based on the sun’s celestial longitude, reflecting the real time points of terrestrial climate changes. This allows for more accurate determination of the month pillar and avoids deviations caused by adjustments in the lunar calendar’s first day.

Question: Why is the sun’s celestial longitude set at 225° for the Lidong solar term? Answer: The 24 solar terms divide the sun’s 360° path along the ecliptic equally into 24 parts, each interval being 15°. Lidong, as the nineteenth solar term, corresponds to 18 × 15° = 225°, marking the beginning of winter.