Acquired Ba-gua and the Seasons

Yi-jing is Natural Science, in fact the very basic Natural Science. Like seasons, the Winter, the Summer and all that.

In the same paragraph of “Shuo-gua” (說卦), a commentary of Zhou-yi, explaining the Acquired Ba-gua, it highlights only “Dui” (兌) as for Autumn. We can imagine the rest of them do represent different seasons as well. The question is which is which.

If Dui represents Autumn, then it must be mid-Autumn, or “Qiu-fen” (秋分), or Autumnal Equinox as what the western astronomy calls. As such, “Zhen” (震) would be mid-Spring, or “Chun-fen” (春分), or Vernal Equinox, while “Kan” (坎) and “Li” (離) must be Winter Solstice (冬至 or “Dong-zhi”) and Summer Solstice (夏至 or “Xia-zhi”) respectively.

In 24 Solar Segments, we know that between Winter Solstice and Vernal Equinox, there is “Li-chun” (立春), or Beginning of Spring, in the middle, so the trigram in the Acquired Ba-gua must be “Gen” (艮). Similarly, “Xun” (巽) will be “Li-xia” (立夏) or Beginning of Summer, “Kun” (坤) as “Li-qiu” (立秋) or Beginning of Autumn, and “Qian” (乾) as “Li-dong” (立冬) or Beginning of Winter.

Oh, almost forgot…. Aries is in Dui, Cancer in Li, while Libra in Zhen and Capricorn in Kan.