There are only two well-known works by Ni Haixia. One is Tian Ji, and the other is Ren Ji. Ni Haixia, another geography, died before it was handed down from generation to generation. Generally speaking, human discipline means medical skills and learning medicine. Tianji is a fortune teller, numerology. So how can we get twice the result with half the effort?
It doesn't matter which one you look at first, Liang Dong's dialogue with Ni Haixia first, and then:
If it's human discipline, you should look at acupuncture, Shennong's Materia Medica, Huangdi's Internal Classic, Treatise on Febrile Diseases and Synopsis of the Golden Chamber in turn. Then look at the clinical case video and the eight-point syndrome differentiation, and finally look at the practice of medical records.
If it's the celestial age, read the Six Rens, the Ziwei Dou and the Yijing in turn, and finally read those cases.