Foundations
Yin and Yang
The complementary two-pole polarity assigned to every stem, branch, and element.
In BaZi, yin and yang are the two complementary poles — receptive and active — carried by every heavenly stem, earthly branch, and element. The polarity pairing is structural: it is one input to how the Five Elements and the Ten Gods are derived, and it is part of why the sexagenary cycle has sixty combinations rather than one hundred and twenty. The system uses the polarity descriptively, as a relationship marker, not as a value judgment.